From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from lists.gentoo.org (pigeon.gentoo.org [208.92.234.80]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by finch.gentoo.org (Postfix) with ESMTPS id 3A8F2138335 for ; Wed, 14 Nov 2018 11:37:57 +0000 (UTC) Received: from pigeon.gentoo.org (localhost [127.0.0.1]) by pigeon.gentoo.org (Postfix) with SMTP id 99B0EE0B33; Wed, 14 Nov 2018 11:37:55 +0000 (UTC) Received: from smtp.gentoo.org (smtp.gentoo.org [140.211.166.183]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by pigeon.gentoo.org (Postfix) with ESMTPS id 280DBE0AFD for ; Wed, 14 Nov 2018 11:37:54 +0000 (UTC) Received: from oystercatcher.gentoo.org (unknown [IPv6:2a01:4f8:202:4333:225:90ff:fed9:fc84]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.gentoo.org (Postfix) with ESMTPS id 87883335C7B for ; Wed, 14 Nov 2018 11:37:53 +0000 (UTC) Received: from localhost.localdomain (localhost [IPv6:::1]) by oystercatcher.gentoo.org (Postfix) with ESMTP id 2BBAE468 for ; Wed, 14 Nov 2018 11:37:51 +0000 (UTC) From: "Mike Pagano" To: gentoo-commits@lists.gentoo.org Content-Transfer-Encoding: 8bit Content-type: text/plain; charset=UTF-8 Reply-To: gentoo-dev@lists.gentoo.org, "Mike Pagano" Message-ID: <1542195380.5dbc4df565362a677f46e44f9592b809bc552f2d.mpagano@gentoo> Subject: [gentoo-commits] proj/linux-patches:4.18 commit in: / X-VCS-Repository: proj/linux-patches X-VCS-Files: 0000_README 1000_linux-4.18.1.patch X-VCS-Directories: / X-VCS-Committer: mpagano X-VCS-Committer-Name: Mike Pagano X-VCS-Revision: 5dbc4df565362a677f46e44f9592b809bc552f2d X-VCS-Branch: 4.18 Date: Wed, 14 Nov 2018 11:37:51 +0000 (UTC) Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-Id: Gentoo Linux mail X-BeenThere: gentoo-commits@lists.gentoo.org X-Archives-Salt: bbabb2c5-d102-47ff-8790-8eb168e28d7f X-Archives-Hash: 29a2916b276abbd1779f96578b3465c8 commit: 5dbc4df565362a677f46e44f9592b809bc552f2d Author: Mike Pagano gentoo org> AuthorDate: Wed Aug 15 16:36:52 2018 +0000 Commit: Mike Pagano gentoo org> CommitDate: Wed Nov 14 11:36:20 2018 +0000 URL: https://gitweb.gentoo.org/proj/linux-patches.git/commit/?id=5dbc4df5 Linuxpatch 4.18.1 Signed-off-by: Mike Pagano gentoo.org> 0000_README | 4 + 1000_linux-4.18.1.patch | 4083 +++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 4087 insertions(+) diff --git a/0000_README b/0000_README index 917d838..cf32ff2 100644 --- a/0000_README +++ b/0000_README @@ -43,6 +43,10 @@ EXPERIMENTAL Individual Patch Descriptions: -------------------------------------------------------------------------- +Patch: 1000_linux-4.18.1.patch +From: http://www.kernel.org +Desc: Linux 4.18.1 + Patch: 1500_XATTR_USER_PREFIX.patch From: https://bugs.gentoo.org/show_bug.cgi?id=470644 Desc: Support for namespace user.pax.* on tmpfs. diff --git a/1000_linux-4.18.1.patch b/1000_linux-4.18.1.patch new file mode 100644 index 0000000..bd9c2da --- /dev/null +++ b/1000_linux-4.18.1.patch @@ -0,0 +1,4083 @@ +diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu +index 9c5e7732d249..73318225a368 100644 +--- a/Documentation/ABI/testing/sysfs-devices-system-cpu ++++ b/Documentation/ABI/testing/sysfs-devices-system-cpu +@@ -476,6 +476,7 @@ What: /sys/devices/system/cpu/vulnerabilities + /sys/devices/system/cpu/vulnerabilities/spectre_v1 + /sys/devices/system/cpu/vulnerabilities/spectre_v2 + /sys/devices/system/cpu/vulnerabilities/spec_store_bypass ++ /sys/devices/system/cpu/vulnerabilities/l1tf + Date: January 2018 + Contact: Linux kernel mailing list + Description: Information about CPU vulnerabilities +@@ -487,3 +488,26 @@ Description: Information about CPU vulnerabilities + "Not affected" CPU is not affected by the vulnerability + "Vulnerable" CPU is affected and no mitigation in effect + "Mitigation: $M" CPU is affected and mitigation $M is in effect ++ ++ Details about the l1tf file can be found in ++ Documentation/admin-guide/l1tf.rst ++ ++What: /sys/devices/system/cpu/smt ++ /sys/devices/system/cpu/smt/active ++ /sys/devices/system/cpu/smt/control ++Date: June 2018 ++Contact: Linux kernel mailing list ++Description: Control Symetric Multi Threading (SMT) ++ ++ active: Tells whether SMT is active (enabled and siblings online) ++ ++ control: Read/write interface to control SMT. Possible ++ values: ++ ++ "on" SMT is enabled ++ "off" SMT is disabled ++ "forceoff" SMT is force disabled. Cannot be changed. ++ "notsupported" SMT is not supported by the CPU ++ ++ If control status is "forceoff" or "notsupported" writes ++ are rejected. +diff --git a/Documentation/admin-guide/index.rst b/Documentation/admin-guide/index.rst +index 48d70af11652..0873685bab0f 100644 +--- a/Documentation/admin-guide/index.rst ++++ b/Documentation/admin-guide/index.rst +@@ -17,6 +17,15 @@ etc. + kernel-parameters + devices + ++This section describes CPU vulnerabilities and provides an overview of the ++possible mitigations along with guidance for selecting mitigations if they ++are configurable at compile, boot or run time. ++ ++.. toctree:: ++ :maxdepth: 1 ++ ++ l1tf ++ + Here is a set of documents aimed at users who are trying to track down + problems and bugs in particular. + +diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt +index 533ff5c68970..1370b424a453 100644 +--- a/Documentation/admin-guide/kernel-parameters.txt ++++ b/Documentation/admin-guide/kernel-parameters.txt +@@ -1967,10 +1967,84 @@ + (virtualized real and unpaged mode) on capable + Intel chips. Default is 1 (enabled) + ++ kvm-intel.vmentry_l1d_flush=[KVM,Intel] Mitigation for L1 Terminal Fault ++ CVE-2018-3620. ++ ++ Valid arguments: never, cond, always ++ ++ always: L1D cache flush on every VMENTER. ++ cond: Flush L1D on VMENTER only when the code between ++ VMEXIT and VMENTER can leak host memory. ++ never: Disables the mitigation ++ ++ Default is cond (do L1 cache flush in specific instances) ++ + kvm-intel.vpid= [KVM,Intel] Disable Virtual Processor Identification + feature (tagged TLBs) on capable Intel chips. + Default is 1 (enabled) + ++ l1tf= [X86] Control mitigation of the L1TF vulnerability on ++ affected CPUs ++ ++ The kernel PTE inversion protection is unconditionally ++ enabled and cannot be disabled. ++ ++ full ++ Provides all available mitigations for the ++ L1TF vulnerability. Disables SMT and ++ enables all mitigations in the ++ hypervisors, i.e. unconditional L1D flush. ++ ++ SMT control and L1D flush control via the ++ sysfs interface is still possible after ++ boot. Hypervisors will issue a warning ++ when the first VM is started in a ++ potentially insecure configuration, ++ i.e. SMT enabled or L1D flush disabled. ++ ++ full,force ++ Same as 'full', but disables SMT and L1D ++ flush runtime control. Implies the ++ 'nosmt=force' command line option. ++ (i.e. sysfs control of SMT is disabled.) ++ ++ flush ++ Leaves SMT enabled and enables the default ++ hypervisor mitigation, i.e. conditional ++ L1D flush. ++ ++ SMT control and L1D flush control via the ++ sysfs interface is still possible after ++ boot. Hypervisors will issue a warning ++ when the first VM is started in a ++ potentially insecure configuration, ++ i.e. SMT enabled or L1D flush disabled. ++ ++ flush,nosmt ++ ++ Disables SMT and enables the default ++ hypervisor mitigation. ++ ++ SMT control and L1D flush control via the ++ sysfs interface is still possible after ++ boot. Hypervisors will issue a warning ++ when the first VM is started in a ++ potentially insecure configuration, ++ i.e. SMT enabled or L1D flush disabled. ++ ++ flush,nowarn ++ Same as 'flush', but hypervisors will not ++ warn when a VM is started in a potentially ++ insecure configuration. ++ ++ off ++ Disables hypervisor mitigations and doesn't ++ emit any warnings. ++ ++ Default is 'flush'. ++ ++ For details see: Documentation/admin-guide/l1tf.rst ++ + l2cr= [PPC] + + l3cr= [PPC] +@@ -2687,6 +2761,10 @@ + nosmt [KNL,S390] Disable symmetric multithreading (SMT). + Equivalent to smt=1. + ++ [KNL,x86] Disable symmetric multithreading (SMT). ++ nosmt=force: Force disable SMT, cannot be undone ++ via the sysfs control file. ++ + nospectre_v2 [X86] Disable all mitigations for the Spectre variant 2 + (indirect branch prediction) vulnerability. System may + allow data leaks with this option, which is equivalent +diff --git a/Documentation/admin-guide/l1tf.rst b/Documentation/admin-guide/l1tf.rst +new file mode 100644 +index 000000000000..bae52b845de0 +--- /dev/null ++++ b/Documentation/admin-guide/l1tf.rst +@@ -0,0 +1,610 @@ ++L1TF - L1 Terminal Fault ++======================== ++ ++L1 Terminal Fault is a hardware vulnerability which allows unprivileged ++speculative access to data which is available in the Level 1 Data Cache ++when the page table entry controlling the virtual address, which is used ++for the access, has the Present bit cleared or other reserved bits set. ++ ++Affected processors ++------------------- ++ ++This vulnerability affects a wide range of Intel processors. The ++vulnerability is not present on: ++ ++ - Processors from AMD, Centaur and other non Intel vendors ++ ++ - Older processor models, where the CPU family is < 6 ++ ++ - A range of Intel ATOM processors (Cedarview, Cloverview, Lincroft, ++ Penwell, Pineview, Silvermont, Airmont, Merrifield) ++ ++ - The Intel XEON PHI family ++ ++ - Intel processors which have the ARCH_CAP_RDCL_NO bit set in the ++ IA32_ARCH_CAPABILITIES MSR. If the bit is set the CPU is not affected ++ by the Meltdown vulnerability either. These CPUs should become ++ available by end of 2018. ++ ++Whether a processor is affected or not can be read out from the L1TF ++vulnerability file in sysfs. See :ref:`l1tf_sys_info`. ++ ++Related CVEs ++------------ ++ ++The following CVE entries are related to the L1TF vulnerability: ++ ++ ============= ================= ============================== ++ CVE-2018-3615 L1 Terminal Fault SGX related aspects ++ CVE-2018-3620 L1 Terminal Fault OS, SMM related aspects ++ CVE-2018-3646 L1 Terminal Fault Virtualization related aspects ++ ============= ================= ============================== ++ ++Problem ++------- ++ ++If an instruction accesses a virtual address for which the relevant page ++table entry (PTE) has the Present bit cleared or other reserved bits set, ++then speculative execution ignores the invalid PTE and loads the referenced ++data if it is present in the Level 1 Data Cache, as if the page referenced ++by the address bits in the PTE was still present and accessible. ++ ++While this is a purely speculative mechanism and the instruction will raise ++a page fault when it is retired eventually, the pure act of loading the ++data and making it available to other speculative instructions opens up the ++opportunity for side channel attacks to unprivileged malicious code, ++similar to the Meltdown attack. ++ ++While Meltdown breaks the user space to kernel space protection, L1TF ++allows to attack any physical memory address in the system and the attack ++works across all protection domains. It allows an attack of SGX and also ++works from inside virtual machines because the speculation bypasses the ++extended page table (EPT) protection mechanism. ++ ++ ++Attack scenarios ++---------------- ++ ++1. Malicious user space ++^^^^^^^^^^^^^^^^^^^^^^^ ++ ++ Operating Systems store arbitrary information in the address bits of a ++ PTE which is marked non present. This allows a malicious user space ++ application to attack the physical memory to which these PTEs resolve. ++ In some cases user-space can maliciously influence the information ++ encoded in the address bits of the PTE, thus making attacks more ++ deterministic and more practical. ++ ++ The Linux kernel contains a mitigation for this attack vector, PTE ++ inversion, which is permanently enabled and has no performance ++ impact. The kernel ensures that the address bits of PTEs, which are not ++ marked present, never point to cacheable physical memory space. ++ ++ A system with an up to date kernel is protected against attacks from ++ malicious user space applications. ++ ++2. Malicious guest in a virtual machine ++^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ++ ++ The fact that L1TF breaks all domain protections allows malicious guest ++ OSes, which can control the PTEs directly, and malicious guest user ++ space applications, which run on an unprotected guest kernel lacking the ++ PTE inversion mitigation for L1TF, to attack physical host memory. ++ ++ A special aspect of L1TF in the context of virtualization is symmetric ++ multi threading (SMT). The Intel implementation of SMT is called ++ HyperThreading. The fact that Hyperthreads on the affected processors ++ share the L1 Data Cache (L1D) is important for this. As the flaw allows ++ only to attack data which is present in L1D, a malicious guest running ++ on one Hyperthread can attack the data which is brought into the L1D by ++ the context which runs on the sibling Hyperthread of the same physical ++ core. This context can be host OS, host user space or a different guest. ++ ++ If the processor does not support Extended Page Tables, the attack is ++ only possible, when the hypervisor does not sanitize the content of the ++ effective (shadow) page tables. ++ ++ While solutions exist to mitigate these attack vectors fully, these ++ mitigations are not enabled by default in the Linux kernel because they ++ can affect performance significantly. The kernel provides several ++ mechanisms which can be utilized to address the problem depending on the ++ deployment scenario. The mitigations, their protection scope and impact ++ are described in the next sections. ++ ++ The default mitigations and the rationale for choosing them are explained ++ at the end of this document. See :ref:`default_mitigations`. ++ ++.. _l1tf_sys_info: ++ ++L1TF system information ++----------------------- ++ ++The Linux kernel provides a sysfs interface to enumerate the current L1TF ++status of the system: whether the system is vulnerable, and which ++mitigations are active. The relevant sysfs file is: ++ ++/sys/devices/system/cpu/vulnerabilities/l1tf ++ ++The possible values in this file are: ++ ++ =========================== =============================== ++ 'Not affected' The processor is not vulnerable ++ 'Mitigation: PTE Inversion' The host protection is active ++ =========================== =============================== ++ ++If KVM/VMX is enabled and the processor is vulnerable then the following ++information is appended to the 'Mitigation: PTE Inversion' part: ++ ++ - SMT status: ++ ++ ===================== ================ ++ 'VMX: SMT vulnerable' SMT is enabled ++ 'VMX: SMT disabled' SMT is disabled ++ ===================== ================ ++ ++ - L1D Flush mode: ++ ++ ================================ ==================================== ++ 'L1D vulnerable' L1D flushing is disabled ++ ++ 'L1D conditional cache flushes' L1D flush is conditionally enabled ++ ++ 'L1D cache flushes' L1D flush is unconditionally enabled ++ ================================ ==================================== ++ ++The resulting grade of protection is discussed in the following sections. ++ ++ ++Host mitigation mechanism ++------------------------- ++ ++The kernel is unconditionally protected against L1TF attacks from malicious ++user space running on the host. ++ ++ ++Guest mitigation mechanisms ++--------------------------- ++ ++.. _l1d_flush: ++ ++1. L1D flush on VMENTER ++^^^^^^^^^^^^^^^^^^^^^^^ ++ ++ To make sure that a guest cannot attack data which is present in the L1D ++ the hypervisor flushes the L1D before entering the guest. ++ ++ Flushing the L1D evicts not only the data which should not be accessed ++ by a potentially malicious guest, it also flushes the guest ++ data. Flushing the L1D has a performance impact as the processor has to ++ bring the flushed guest data back into the L1D. Depending on the ++ frequency of VMEXIT/VMENTER and the type of computations in the guest ++ performance degradation in the range of 1% to 50% has been observed. For ++ scenarios where guest VMEXIT/VMENTER are rare the performance impact is ++ minimal. Virtio and mechanisms like posted interrupts are designed to ++ confine the VMEXITs to a bare minimum, but specific configurations and ++ application scenarios might still suffer from a high VMEXIT rate. ++ ++ The kernel provides two L1D flush modes: ++ - conditional ('cond') ++ - unconditional ('always') ++ ++ The conditional mode avoids L1D flushing after VMEXITs which execute ++ only audited code paths before the corresponding VMENTER. These code ++ paths have been verified that they cannot expose secrets or other ++ interesting data to an attacker, but they can leak information about the ++ address space layout of the hypervisor. ++ ++ Unconditional mode flushes L1D on all VMENTER invocations and provides ++ maximum protection. It has a higher overhead than the conditional ++ mode. The overhead cannot be quantified correctly as it depends on the ++ workload scenario and the resulting number of VMEXITs. ++ ++ The general recommendation is to enable L1D flush on VMENTER. The kernel ++ defaults to conditional mode on affected processors. ++ ++ **Note**, that L1D flush does not prevent the SMT problem because the ++ sibling thread will also bring back its data into the L1D which makes it ++ attackable again. ++ ++ L1D flush can be controlled by the administrator via the kernel command ++ line and sysfs control files. See :ref:`mitigation_control_command_line` ++ and :ref:`mitigation_control_kvm`. ++ ++.. _guest_confinement: ++ ++2. Guest VCPU confinement to dedicated physical cores ++^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ++ ++ To address the SMT problem, it is possible to make a guest or a group of ++ guests affine to one or more physical cores. The proper mechanism for ++ that is to utilize exclusive cpusets to ensure that no other guest or ++ host tasks can run on these cores. ++ ++ If only a single guest or related guests run on sibling SMT threads on ++ the same physical core then they can only attack their own memory and ++ restricted parts of the host memory. ++ ++ Host memory is attackable, when one of the sibling SMT threads runs in ++ host OS (hypervisor) context and the other in guest context. The amount ++ of valuable information from the host OS context depends on the context ++ which the host OS executes, i.e. interrupts, soft interrupts and kernel ++ threads. The amount of valuable data from these contexts cannot be ++ declared as non-interesting for an attacker without deep inspection of ++ the code. ++ ++ **Note**, that assigning guests to a fixed set of physical cores affects ++ the ability of the scheduler to do load balancing and might have ++ negative effects on CPU utilization depending on the hosting ++ scenario. Disabling SMT might be a viable alternative for particular ++ scenarios. ++ ++ For further information about confining guests to a single or to a group ++ of cores consult the cpusets documentation: ++ ++ https://www.kernel.org/doc/Documentation/cgroup-v1/cpusets.txt ++ ++.. _interrupt_isolation: ++ ++3. Interrupt affinity ++^^^^^^^^^^^^^^^^^^^^^ ++ ++ Interrupts can be made affine to logical CPUs. This is not universally ++ true because there are types of interrupts which are truly per CPU ++ interrupts, e.g. the local timer interrupt. Aside of that multi queue ++ devices affine their interrupts to single CPUs or groups of CPUs per ++ queue without allowing the administrator to control the affinities. ++ ++ Moving the interrupts, which can be affinity controlled, away from CPUs ++ which run untrusted guests, reduces the attack vector space. ++ ++ Whether the interrupts with are affine to CPUs, which run untrusted ++ guests, provide interesting data for an attacker depends on the system ++ configuration and the scenarios which run on the system. While for some ++ of the interrupts it can be assumed that they won't expose interesting ++ information beyond exposing hints about the host OS memory layout, there ++ is no way to make general assumptions. ++ ++ Interrupt affinity can be controlled by the administrator via the ++ /proc/irq/$NR/smp_affinity[_list] files. Limited documentation is ++ available at: ++ ++ https://www.kernel.org/doc/Documentation/IRQ-affinity.txt ++ ++.. _smt_control: ++ ++4. SMT control ++^^^^^^^^^^^^^^ ++ ++ To prevent the SMT issues of L1TF it might be necessary to disable SMT ++ completely. Disabling SMT can have a significant performance impact, but ++ the impact depends on the hosting scenario and the type of workloads. ++ The impact of disabling SMT needs also to be weighted against the impact ++ of other mitigation solutions like confining guests to dedicated cores. ++ ++ The kernel provides a sysfs interface to retrieve the status of SMT and ++ to control it. It also provides a kernel command line interface to ++ control SMT. ++ ++ The kernel command line interface consists of the following options: ++ ++ =========== ========================================================== ++ nosmt Affects the bring up of the secondary CPUs during boot. The ++ kernel tries to bring all present CPUs online during the ++ boot process. "nosmt" makes sure that from each physical ++ core only one - the so called primary (hyper) thread is ++ activated. Due to a design flaw of Intel processors related ++ to Machine Check Exceptions the non primary siblings have ++ to be brought up at least partially and are then shut down ++ again. "nosmt" can be undone via the sysfs interface. ++ ++ nosmt=force Has the same effect as "nosmt" but it does not allow to ++ undo the SMT disable via the sysfs interface. ++ =========== ========================================================== ++ ++ The sysfs interface provides two files: ++ ++ - /sys/devices/system/cpu/smt/control ++ - /sys/devices/system/cpu/smt/active ++ ++ /sys/devices/system/cpu/smt/control: ++ ++ This file allows to read out the SMT control state and provides the ++ ability to disable or (re)enable SMT. The possible states are: ++ ++ ============== =================================================== ++ on SMT is supported by the CPU and enabled. All ++ logical CPUs can be onlined and offlined without ++ restrictions. ++ ++ off SMT is supported by the CPU and disabled. Only ++ the so called primary SMT threads can be onlined ++ and offlined without restrictions. An attempt to ++ online a non-primary sibling is rejected ++ ++ forceoff Same as 'off' but the state cannot be controlled. ++ Attempts to write to the control file are rejected. ++ ++ notsupported The processor does not support SMT. It's therefore ++ not affected by the SMT implications of L1TF. ++ Attempts to write to the control file are rejected. ++ ============== =================================================== ++ ++ The possible states which can be written into this file to control SMT ++ state are: ++ ++ - on ++ - off ++ - forceoff ++ ++ /sys/devices/system/cpu/smt/active: ++ ++ This file reports whether SMT is enabled and active, i.e. if on any ++ physical core two or more sibling threads are online. ++ ++ SMT control is also possible at boot time via the l1tf kernel command ++ line parameter in combination with L1D flush control. See ++ :ref:`mitigation_control_command_line`. ++ ++5. Disabling EPT ++^^^^^^^^^^^^^^^^ ++ ++ Disabling EPT for virtual machines provides full mitigation for L1TF even ++ with SMT enabled, because the effective page tables for guests are ++ managed and sanitized by the hypervisor. Though disabling EPT has a ++ significant performance impact especially when the Meltdown mitigation ++ KPTI is enabled. ++ ++ EPT can be disabled in the hypervisor via the 'kvm-intel.ept' parameter. ++ ++There is ongoing research and development for new mitigation mechanisms to ++address the performance impact of disabling SMT or EPT. ++ ++.. _mitigation_control_command_line: ++ ++Mitigation control on the kernel command line ++--------------------------------------------- ++ ++The kernel command line allows to control the L1TF mitigations at boot ++time with the option "l1tf=". The valid arguments for this option are: ++ ++ ============ ============================================================= ++ full Provides all available mitigations for the L1TF ++ vulnerability. Disables SMT and enables all mitigations in ++ the hypervisors, i.e. unconditional L1D flushing ++ ++ SMT control and L1D flush control via the sysfs interface ++ is still possible after boot. Hypervisors will issue a ++ warning when the first VM is started in a potentially ++ insecure configuration, i.e. SMT enabled or L1D flush ++ disabled. ++ ++ full,force Same as 'full', but disables SMT and L1D flush runtime ++ control. Implies the 'nosmt=force' command line option. ++ (i.e. sysfs control of SMT is disabled.) ++ ++ flush Leaves SMT enabled and enables the default hypervisor ++ mitigation, i.e. conditional L1D flushing ++ ++ SMT control and L1D flush control via the sysfs interface ++ is still possible after boot. Hypervisors will issue a ++ warning when the first VM is started in a potentially ++ insecure configuration, i.e. SMT enabled or L1D flush ++ disabled. ++ ++ flush,nosmt Disables SMT and enables the default hypervisor mitigation, ++ i.e. conditional L1D flushing. ++ ++ SMT control and L1D flush control via the sysfs interface ++ is still possible after boot. Hypervisors will issue a ++ warning when the first VM is started in a potentially ++ insecure configuration, i.e. SMT enabled or L1D flush ++ disabled. ++ ++ flush,nowarn Same as 'flush', but hypervisors will not warn when a VM is ++ started in a potentially insecure configuration. ++ ++ off Disables hypervisor mitigations and doesn't emit any ++ warnings. ++ ============ ============================================================= ++ ++The default is 'flush'. For details about L1D flushing see :ref:`l1d_flush`. ++ ++ ++.. _mitigation_control_kvm: ++ ++Mitigation control for KVM - module parameter ++------------------------------------------------------------- ++ ++The KVM hypervisor mitigation mechanism, flushing the L1D cache when ++entering a guest, can be controlled with a module parameter. ++ ++The option/parameter is "kvm-intel.vmentry_l1d_flush=". It takes the ++following arguments: ++ ++ ============ ============================================================== ++ always L1D cache flush on every VMENTER. ++ ++ cond Flush L1D on VMENTER only when the code between VMEXIT and ++ VMENTER can leak host memory which is considered ++ interesting for an attacker. This still can leak host memory ++ which allows e.g. to determine the hosts address space layout. ++ ++ never Disables the mitigation ++ ============ ============================================================== ++ ++The parameter can be provided on the kernel command line, as a module ++parameter when loading the modules and at runtime modified via the sysfs ++file: ++ ++/sys/module/kvm_intel/parameters/vmentry_l1d_flush ++ ++The default is 'cond'. If 'l1tf=full,force' is given on the kernel command ++line, then 'always' is enforced and the kvm-intel.vmentry_l1d_flush ++module parameter is ignored and writes to the sysfs file are rejected. ++ ++ ++Mitigation selection guide ++-------------------------- ++ ++1. No virtualization in use ++^^^^^^^^^^^^^^^^^^^^^^^^^^^ ++ ++ The system is protected by the kernel unconditionally and no further ++ action is required. ++ ++2. Virtualization with trusted guests ++^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ++ ++ If the guest comes from a trusted source and the guest OS kernel is ++ guaranteed to have the L1TF mitigations in place the system is fully ++ protected against L1TF and no further action is required. ++ ++ To avoid the overhead of the default L1D flushing on VMENTER the ++ administrator can disable the flushing via the kernel command line and ++ sysfs control files. See :ref:`mitigation_control_command_line` and ++ :ref:`mitigation_control_kvm`. ++ ++ ++3. Virtualization with untrusted guests ++^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ++ ++3.1. SMT not supported or disabled ++"""""""""""""""""""""""""""""""""" ++ ++ If SMT is not supported by the processor or disabled in the BIOS or by ++ the kernel, it's only required to enforce L1D flushing on VMENTER. ++ ++ Conditional L1D flushing is the default behaviour and can be tuned. See ++ :ref:`mitigation_control_command_line` and :ref:`mitigation_control_kvm`. ++ ++3.2. EPT not supported or disabled ++"""""""""""""""""""""""""""""""""" ++ ++ If EPT is not supported by the processor or disabled in the hypervisor, ++ the system is fully protected. SMT can stay enabled and L1D flushing on ++ VMENTER is not required. ++ ++ EPT can be disabled in the hypervisor via the 'kvm-intel.ept' parameter. ++ ++3.3. SMT and EPT supported and active ++""""""""""""""""""""""""""""""""""""" ++ ++ If SMT and EPT are supported and active then various degrees of ++ mitigations can be employed: ++ ++ - L1D flushing on VMENTER: ++ ++ L1D flushing on VMENTER is the minimal protection requirement, but it ++ is only potent in combination with other mitigation methods. ++ ++ Conditional L1D flushing is the default behaviour and can be tuned. See ++ :ref:`mitigation_control_command_line` and :ref:`mitigation_control_kvm`. ++ ++ - Guest confinement: ++ ++ Confinement of guests to a single or a group of physical cores which ++ are not running any other processes, can reduce the attack surface ++ significantly, but interrupts, soft interrupts and kernel threads can ++ still expose valuable data to a potential attacker. See ++ :ref:`guest_confinement`. ++ ++ - Interrupt isolation: ++ ++ Isolating the guest CPUs from interrupts can reduce the attack surface ++ further, but still allows a malicious guest to explore a limited amount ++ of host physical memory. This can at least be used to gain knowledge ++ about the host address space layout. The interrupts which have a fixed ++ affinity to the CPUs which run the untrusted guests can depending on ++ the scenario still trigger soft interrupts and schedule kernel threads ++ which might expose valuable information. See ++ :ref:`interrupt_isolation`. ++ ++The above three mitigation methods combined can provide protection to a ++certain degree, but the risk of the remaining attack surface has to be ++carefully analyzed. For full protection the following methods are ++available: ++ ++ - Disabling SMT: ++ ++ Disabling SMT and enforcing the L1D flushing provides the maximum ++ amount of protection. This mitigation is not depending on any of the ++ above mitigation methods. ++ ++ SMT control and L1D flushing can be tuned by the command line ++ parameters 'nosmt', 'l1tf', 'kvm-intel.vmentry_l1d_flush' and at run ++ time with the matching sysfs control files. See :ref:`smt_control`, ++ :ref:`mitigation_control_command_line` and ++ :ref:`mitigation_control_kvm`. ++ ++ - Disabling EPT: ++ ++ Disabling EPT provides the maximum amount of protection as well. It is ++ not depending on any of the above mitigation methods. SMT can stay ++ enabled and L1D flushing is not required, but the performance impact is ++ significant. ++ ++ EPT can be disabled in the hypervisor via the 'kvm-intel.ept' ++ parameter. ++ ++3.4. Nested virtual machines ++"""""""""""""""""""""""""""" ++ ++When nested virtualization is in use, three operating systems are involved: ++the bare metal hypervisor, the nested hypervisor and the nested virtual ++machine. VMENTER operations from the nested hypervisor into the nested ++guest will always be processed by the bare metal hypervisor. If KVM is the ++bare metal hypervisor it wiil: ++ ++ - Flush the L1D cache on every switch from the nested hypervisor to the ++ nested virtual machine, so that the nested hypervisor's secrets are not ++ exposed to the nested virtual machine; ++ ++ - Flush the L1D cache on every switch from the nested virtual machine to ++ the nested hypervisor; this is a complex operation, and flushing the L1D ++ cache avoids that the bare metal hypervisor's secrets are exposed to the ++ nested virtual machine; ++ ++ - Instruct the nested hypervisor to not perform any L1D cache flush. This ++ is an optimization to avoid double L1D flushing. ++ ++ ++.. _default_mitigations: ++ ++Default mitigations ++------------------- ++ ++ The kernel default mitigations for vulnerable processors are: ++ ++ - PTE inversion to protect against malicious user space. This is done ++ unconditionally and cannot be controlled. ++ ++ - L1D conditional flushing on VMENTER when EPT is enabled for ++ a guest. ++ ++ The kernel does not by default enforce the disabling of SMT, which leaves ++ SMT systems vulnerable when running untrusted guests with EPT enabled. ++ ++ The rationale for this choice is: ++ ++ - Force disabling SMT can break existing setups, especially with ++ unattended updates. ++ ++ - If regular users run untrusted guests on their machine, then L1TF is ++ just an add on to other malware which might be embedded in an untrusted ++ guest, e.g. spam-bots or attacks on the local network. ++ ++ There is no technical way to prevent a user from running untrusted code ++ on their machines blindly. ++ ++ - It's technically extremely unlikely and from today's knowledge even ++ impossible that L1TF can be exploited via the most popular attack ++ mechanisms like JavaScript because these mechanisms have no way to ++ control PTEs. If this would be possible and not other mitigation would ++ be possible, then the default might be different. ++ ++ - The administrators of cloud and hosting setups have to carefully ++ analyze the risk for their scenarios and make the appropriate ++ mitigation choices, which might even vary across their deployed ++ machines and also result in other changes of their overall setup. ++ There is no way for the kernel to provide a sensible default for this ++ kind of scenarios. +diff --git a/Makefile b/Makefile +index 863f58503bee..5edf963148e8 100644 +--- a/Makefile ++++ b/Makefile +@@ -1,7 +1,7 @@ + # SPDX-License-Identifier: GPL-2.0 + VERSION = 4 + PATCHLEVEL = 18 +-SUBLEVEL = 0 ++SUBLEVEL = 1 + EXTRAVERSION = + NAME = Merciless Moray + +diff --git a/arch/Kconfig b/arch/Kconfig +index 1aa59063f1fd..d1f2ed462ac8 100644 +--- a/arch/Kconfig ++++ b/arch/Kconfig +@@ -13,6 +13,9 @@ config KEXEC_CORE + config HAVE_IMA_KEXEC + bool + ++config HOTPLUG_SMT ++ bool ++ + config OPROFILE + tristate "OProfile system profiling" + depends on PROFILING +diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig +index 887d3a7bb646..6b8065d718bd 100644 +--- a/arch/x86/Kconfig ++++ b/arch/x86/Kconfig +@@ -187,6 +187,7 @@ config X86 + select HAVE_SYSCALL_TRACEPOINTS + select HAVE_UNSTABLE_SCHED_CLOCK + select HAVE_USER_RETURN_NOTIFIER ++ select HOTPLUG_SMT if SMP + select IRQ_FORCED_THREADING + select NEED_SG_DMA_LENGTH + select PCI_LOCKLESS_CONFIG +diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h +index 74a9e06b6cfd..130e81e10fc7 100644 +--- a/arch/x86/include/asm/apic.h ++++ b/arch/x86/include/asm/apic.h +@@ -10,6 +10,7 @@ + #include + #include + #include ++#include + + #define ARCH_APICTIMER_STOPS_ON_C3 1 + +@@ -502,12 +503,19 @@ extern int default_check_phys_apicid_present(int phys_apicid); + + #endif /* CONFIG_X86_LOCAL_APIC */ + ++#ifdef CONFIG_SMP ++bool apic_id_is_primary_thread(unsigned int id); ++#else ++static inline bool apic_id_is_primary_thread(unsigned int id) { return false; } ++#endif ++ + extern void irq_enter(void); + extern void irq_exit(void); + + static inline void entering_irq(void) + { + irq_enter(); ++ kvm_set_cpu_l1tf_flush_l1d(); + } + + static inline void entering_ack_irq(void) +@@ -520,6 +528,7 @@ static inline void ipi_entering_ack_irq(void) + { + irq_enter(); + ack_APIC_irq(); ++ kvm_set_cpu_l1tf_flush_l1d(); + } + + static inline void exiting_irq(void) +diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h +index 5701f5cecd31..64aaa3f5f36c 100644 +--- a/arch/x86/include/asm/cpufeatures.h ++++ b/arch/x86/include/asm/cpufeatures.h +@@ -219,6 +219,7 @@ + #define X86_FEATURE_IBPB ( 7*32+26) /* Indirect Branch Prediction Barrier */ + #define X86_FEATURE_STIBP ( 7*32+27) /* Single Thread Indirect Branch Predictors */ + #define X86_FEATURE_ZEN ( 7*32+28) /* "" CPU is AMD family 0x17 (Zen) */ ++#define X86_FEATURE_L1TF_PTEINV ( 7*32+29) /* "" L1TF workaround PTE inversion */ + + /* Virtualization flags: Linux defined, word 8 */ + #define X86_FEATURE_TPR_SHADOW ( 8*32+ 0) /* Intel TPR Shadow */ +@@ -341,6 +342,7 @@ + #define X86_FEATURE_PCONFIG (18*32+18) /* Intel PCONFIG */ + #define X86_FEATURE_SPEC_CTRL (18*32+26) /* "" Speculation Control (IBRS + IBPB) */ + #define X86_FEATURE_INTEL_STIBP (18*32+27) /* "" Single Thread Indirect Branch Predictors */ ++#define X86_FEATURE_FLUSH_L1D (18*32+28) /* Flush L1D cache */ + #define X86_FEATURE_ARCH_CAPABILITIES (18*32+29) /* IA32_ARCH_CAPABILITIES MSR (Intel) */ + #define X86_FEATURE_SPEC_CTRL_SSBD (18*32+31) /* "" Speculative Store Bypass Disable */ + +@@ -373,5 +375,6 @@ + #define X86_BUG_SPECTRE_V1 X86_BUG(15) /* CPU is affected by Spectre variant 1 attack with conditional branches */ + #define X86_BUG_SPECTRE_V2 X86_BUG(16) /* CPU is affected by Spectre variant 2 attack with indirect branches */ + #define X86_BUG_SPEC_STORE_BYPASS X86_BUG(17) /* CPU is affected by speculative store bypass attack */ ++#define X86_BUG_L1TF X86_BUG(18) /* CPU is affected by L1 Terminal Fault */ + + #endif /* _ASM_X86_CPUFEATURES_H */ +diff --git a/arch/x86/include/asm/dmi.h b/arch/x86/include/asm/dmi.h +index 0ab2ab27ad1f..b825cb201251 100644 +--- a/arch/x86/include/asm/dmi.h ++++ b/arch/x86/include/asm/dmi.h +@@ -4,8 +4,8 @@ + + #include + #include ++#include + +-#include + #include + + static __always_inline __init void *dmi_alloc(unsigned len) +diff --git a/arch/x86/include/asm/hardirq.h b/arch/x86/include/asm/hardirq.h +index 740a428acf1e..d9069bb26c7f 100644 +--- a/arch/x86/include/asm/hardirq.h ++++ b/arch/x86/include/asm/hardirq.h +@@ -3,10 +3,12 @@ + #define _ASM_X86_HARDIRQ_H + + #include +-#include + + typedef struct { +- unsigned int __softirq_pending; ++ u16 __softirq_pending; ++#if IS_ENABLED(CONFIG_KVM_INTEL) ++ u8 kvm_cpu_l1tf_flush_l1d; ++#endif + unsigned int __nmi_count; /* arch dependent */ + #ifdef CONFIG_X86_LOCAL_APIC + unsigned int apic_timer_irqs; /* arch dependent */ +@@ -58,4 +60,24 @@ extern u64 arch_irq_stat_cpu(unsigned int cpu); + extern u64 arch_irq_stat(void); + #define arch_irq_stat arch_irq_stat + ++ ++#if IS_ENABLED(CONFIG_KVM_INTEL) ++static inline void kvm_set_cpu_l1tf_flush_l1d(void) ++{ ++ __this_cpu_write(irq_stat.kvm_cpu_l1tf_flush_l1d, 1); ++} ++ ++static inline void kvm_clear_cpu_l1tf_flush_l1d(void) ++{ ++ __this_cpu_write(irq_stat.kvm_cpu_l1tf_flush_l1d, 0); ++} ++ ++static inline bool kvm_get_cpu_l1tf_flush_l1d(void) ++{ ++ return __this_cpu_read(irq_stat.kvm_cpu_l1tf_flush_l1d); ++} ++#else /* !IS_ENABLED(CONFIG_KVM_INTEL) */ ++static inline void kvm_set_cpu_l1tf_flush_l1d(void) { } ++#endif /* IS_ENABLED(CONFIG_KVM_INTEL) */ ++ + #endif /* _ASM_X86_HARDIRQ_H */ +diff --git a/arch/x86/include/asm/irqflags.h b/arch/x86/include/asm/irqflags.h +index c4fc17220df9..c14f2a74b2be 100644 +--- a/arch/x86/include/asm/irqflags.h ++++ b/arch/x86/include/asm/irqflags.h +@@ -13,6 +13,8 @@ + * Interrupt control: + */ + ++/* Declaration required for gcc < 4.9 to prevent -Werror=missing-prototypes */ ++extern inline unsigned long native_save_fl(void); + extern inline unsigned long native_save_fl(void) + { + unsigned long flags; +diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h +index c13cd28d9d1b..acebb808c4b5 100644 +--- a/arch/x86/include/asm/kvm_host.h ++++ b/arch/x86/include/asm/kvm_host.h +@@ -17,6 +17,7 @@ + #include + #include + #include ++#include + + #include + #include +@@ -713,6 +714,9 @@ struct kvm_vcpu_arch { + + /* be preempted when it's in kernel-mode(cpl=0) */ + bool preempted_in_kernel; ++ ++ /* Flush the L1 Data cache for L1TF mitigation on VMENTER */ ++ bool l1tf_flush_l1d; + }; + + struct kvm_lpage_info { +@@ -881,6 +885,7 @@ struct kvm_vcpu_stat { + u64 signal_exits; + u64 irq_window_exits; + u64 nmi_window_exits; ++ u64 l1d_flush; + u64 halt_exits; + u64 halt_successful_poll; + u64 halt_attempted_poll; +@@ -1413,6 +1418,7 @@ int kvm_cpu_get_interrupt(struct kvm_vcpu *v); + void kvm_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event); + void kvm_vcpu_reload_apic_access_page(struct kvm_vcpu *vcpu); + ++u64 kvm_get_arch_capabilities(void); + void kvm_define_shared_msr(unsigned index, u32 msr); + int kvm_set_shared_msr(unsigned index, u64 val, u64 mask); + +diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h +index 68b2c3150de1..4731f0cf97c5 100644 +--- a/arch/x86/include/asm/msr-index.h ++++ b/arch/x86/include/asm/msr-index.h +@@ -70,12 +70,19 @@ + #define MSR_IA32_ARCH_CAPABILITIES 0x0000010a + #define ARCH_CAP_RDCL_NO (1 << 0) /* Not susceptible to Meltdown */ + #define ARCH_CAP_IBRS_ALL (1 << 1) /* Enhanced IBRS support */ ++#define ARCH_CAP_SKIP_VMENTRY_L1DFLUSH (1 << 3) /* Skip L1D flush on vmentry */ + #define ARCH_CAP_SSB_NO (1 << 4) /* + * Not susceptible to Speculative Store Bypass + * attack, so no Speculative Store Bypass + * control required. + */ + ++#define MSR_IA32_FLUSH_CMD 0x0000010b ++#define L1D_FLUSH (1 << 0) /* ++ * Writeback and invalidate the ++ * L1 data cache. ++ */ ++ + #define MSR_IA32_BBL_CR_CTL 0x00000119 + #define MSR_IA32_BBL_CR_CTL3 0x0000011e + +diff --git a/arch/x86/include/asm/page_32_types.h b/arch/x86/include/asm/page_32_types.h +index aa30c3241ea7..0d5c739eebd7 100644 +--- a/arch/x86/include/asm/page_32_types.h ++++ b/arch/x86/include/asm/page_32_types.h +@@ -29,8 +29,13 @@ + #define N_EXCEPTION_STACKS 1 + + #ifdef CONFIG_X86_PAE +-/* 44=32+12, the limit we can fit into an unsigned long pfn */ +-#define __PHYSICAL_MASK_SHIFT 44 ++/* ++ * This is beyond the 44 bit limit imposed by the 32bit long pfns, ++ * but we need the full mask to make sure inverted PROT_NONE ++ * entries have all the host bits set in a guest. ++ * The real limit is still 44 bits. ++ */ ++#define __PHYSICAL_MASK_SHIFT 52 + #define __VIRTUAL_MASK_SHIFT 32 + + #else /* !CONFIG_X86_PAE */ +diff --git a/arch/x86/include/asm/pgtable-2level.h b/arch/x86/include/asm/pgtable-2level.h +index 685ffe8a0eaf..60d0f9015317 100644 +--- a/arch/x86/include/asm/pgtable-2level.h ++++ b/arch/x86/include/asm/pgtable-2level.h +@@ -95,4 +95,21 @@ static inline unsigned long pte_bitop(unsigned long value, unsigned int rightshi + #define __pte_to_swp_entry(pte) ((swp_entry_t) { (pte).pte_low }) + #define __swp_entry_to_pte(x) ((pte_t) { .pte = (x).val }) + ++/* No inverted PFNs on 2 level page tables */ ++ ++static inline u64 protnone_mask(u64 val) ++{ ++ return 0; ++} ++ ++static inline u64 flip_protnone_guard(u64 oldval, u64 val, u64 mask) ++{ ++ return val; ++} ++ ++static inline bool __pte_needs_invert(u64 val) ++{ ++ return false; ++} ++ + #endif /* _ASM_X86_PGTABLE_2LEVEL_H */ +diff --git a/arch/x86/include/asm/pgtable-3level.h b/arch/x86/include/asm/pgtable-3level.h +index f24df59c40b2..bb035a4cbc8c 100644 +--- a/arch/x86/include/asm/pgtable-3level.h ++++ b/arch/x86/include/asm/pgtable-3level.h +@@ -241,12 +241,43 @@ static inline pud_t native_pudp_get_and_clear(pud_t *pudp) + #endif + + /* Encode and de-code a swap entry */ ++#define SWP_TYPE_BITS 5 ++ ++#define SWP_OFFSET_FIRST_BIT (_PAGE_BIT_PROTNONE + 1) ++ ++/* We always extract/encode the offset by shifting it all the way up, and then down again */ ++#define SWP_OFFSET_SHIFT (SWP_OFFSET_FIRST_BIT + SWP_TYPE_BITS) ++ + #define MAX_SWAPFILES_CHECK() BUILD_BUG_ON(MAX_SWAPFILES_SHIFT > 5) + #define __swp_type(x) (((x).val) & 0x1f) + #define __swp_offset(x) ((x).val >> 5) + #define __swp_entry(type, offset) ((swp_entry_t){(type) | (offset) << 5}) +-#define __pte_to_swp_entry(pte) ((swp_entry_t){ (pte).pte_high }) +-#define __swp_entry_to_pte(x) ((pte_t){ { .pte_high = (x).val } }) ++ ++/* ++ * Normally, __swp_entry() converts from arch-independent swp_entry_t to ++ * arch-dependent swp_entry_t, and __swp_entry_to_pte() just stores the result ++ * to pte. But here we have 32bit swp_entry_t and 64bit pte, and need to use the ++ * whole 64 bits. Thus, we shift the "real" arch-dependent conversion to ++ * __swp_entry_to_pte() through the following helper macro based on 64bit ++ * __swp_entry(). ++ */ ++#define __swp_pteval_entry(type, offset) ((pteval_t) { \ ++ (~(pteval_t)(offset) << SWP_OFFSET_SHIFT >> SWP_TYPE_BITS) \ ++ | ((pteval_t)(type) << (64 - SWP_TYPE_BITS)) }) ++ ++#define __swp_entry_to_pte(x) ((pte_t){ .pte = \ ++ __swp_pteval_entry(__swp_type(x), __swp_offset(x)) }) ++/* ++ * Analogically, __pte_to_swp_entry() doesn't just extract the arch-dependent ++ * swp_entry_t, but also has to convert it from 64bit to the 32bit ++ * intermediate representation, using the following macros based on 64bit ++ * __swp_type() and __swp_offset(). ++ */ ++#define __pteval_swp_type(x) ((unsigned long)((x).pte >> (64 - SWP_TYPE_BITS))) ++#define __pteval_swp_offset(x) ((unsigned long)(~((x).pte) << SWP_TYPE_BITS >> SWP_OFFSET_SHIFT)) ++ ++#define __pte_to_swp_entry(pte) (__swp_entry(__pteval_swp_type(pte), \ ++ __pteval_swp_offset(pte))) + + #define gup_get_pte gup_get_pte + /* +@@ -295,4 +326,6 @@ static inline pte_t gup_get_pte(pte_t *ptep) + return pte; + } + ++#include ++ + #endif /* _ASM_X86_PGTABLE_3LEVEL_H */ +diff --git a/arch/x86/include/asm/pgtable-invert.h b/arch/x86/include/asm/pgtable-invert.h +new file mode 100644 +index 000000000000..44b1203ece12 +--- /dev/null ++++ b/arch/x86/include/asm/pgtable-invert.h +@@ -0,0 +1,32 @@ ++/* SPDX-License-Identifier: GPL-2.0 */ ++#ifndef _ASM_PGTABLE_INVERT_H ++#define _ASM_PGTABLE_INVERT_H 1 ++ ++#ifndef __ASSEMBLY__ ++ ++static inline bool __pte_needs_invert(u64 val) ++{ ++ return !(val & _PAGE_PRESENT); ++} ++ ++/* Get a mask to xor with the page table entry to get the correct pfn. */ ++static inline u64 protnone_mask(u64 val) ++{ ++ return __pte_needs_invert(val) ? ~0ull : 0; ++} ++ ++static inline u64 flip_protnone_guard(u64 oldval, u64 val, u64 mask) ++{ ++ /* ++ * When a PTE transitions from NONE to !NONE or vice-versa ++ * invert the PFN part to stop speculation. ++ * pte_pfn undoes this when needed. ++ */ ++ if (__pte_needs_invert(oldval) != __pte_needs_invert(val)) ++ val = (val & ~mask) | (~val & mask); ++ return val; ++} ++ ++#endif /* __ASSEMBLY__ */ ++ ++#endif +diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h +index 5715647fc4fe..13125aad804c 100644 +--- a/arch/x86/include/asm/pgtable.h ++++ b/arch/x86/include/asm/pgtable.h +@@ -185,19 +185,29 @@ static inline int pte_special(pte_t pte) + return pte_flags(pte) & _PAGE_SPECIAL; + } + ++/* Entries that were set to PROT_NONE are inverted */ ++ ++static inline u64 protnone_mask(u64 val); ++ + static inline unsigned long pte_pfn(pte_t pte) + { +- return (pte_val(pte) & PTE_PFN_MASK) >> PAGE_SHIFT; ++ phys_addr_t pfn = pte_val(pte); ++ pfn ^= protnone_mask(pfn); ++ return (pfn & PTE_PFN_MASK) >> PAGE_SHIFT; + } + + static inline unsigned long pmd_pfn(pmd_t pmd) + { +- return (pmd_val(pmd) & pmd_pfn_mask(pmd)) >> PAGE_SHIFT; ++ phys_addr_t pfn = pmd_val(pmd); ++ pfn ^= protnone_mask(pfn); ++ return (pfn & pmd_pfn_mask(pmd)) >> PAGE_SHIFT; + } + + static inline unsigned long pud_pfn(pud_t pud) + { +- return (pud_val(pud) & pud_pfn_mask(pud)) >> PAGE_SHIFT; ++ phys_addr_t pfn = pud_val(pud); ++ pfn ^= protnone_mask(pfn); ++ return (pfn & pud_pfn_mask(pud)) >> PAGE_SHIFT; + } + + static inline unsigned long p4d_pfn(p4d_t p4d) +@@ -400,11 +410,6 @@ static inline pmd_t pmd_mkwrite(pmd_t pmd) + return pmd_set_flags(pmd, _PAGE_RW); + } + +-static inline pmd_t pmd_mknotpresent(pmd_t pmd) +-{ +- return pmd_clear_flags(pmd, _PAGE_PRESENT | _PAGE_PROTNONE); +-} +- + static inline pud_t pud_set_flags(pud_t pud, pudval_t set) + { + pudval_t v = native_pud_val(pud); +@@ -459,11 +464,6 @@ static inline pud_t pud_mkwrite(pud_t pud) + return pud_set_flags(pud, _PAGE_RW); + } + +-static inline pud_t pud_mknotpresent(pud_t pud) +-{ +- return pud_clear_flags(pud, _PAGE_PRESENT | _PAGE_PROTNONE); +-} +- + #ifdef CONFIG_HAVE_ARCH_SOFT_DIRTY + static inline int pte_soft_dirty(pte_t pte) + { +@@ -545,25 +545,45 @@ static inline pgprotval_t check_pgprot(pgprot_t pgprot) + + static inline pte_t pfn_pte(unsigned long page_nr, pgprot_t pgprot) + { +- return __pte(((phys_addr_t)page_nr << PAGE_SHIFT) | +- check_pgprot(pgprot)); ++ phys_addr_t pfn = (phys_addr_t)page_nr << PAGE_SHIFT; ++ pfn ^= protnone_mask(pgprot_val(pgprot)); ++ pfn &= PTE_PFN_MASK; ++ return __pte(pfn | check_pgprot(pgprot)); + } + + static inline pmd_t pfn_pmd(unsigned long page_nr, pgprot_t pgprot) + { +- return __pmd(((phys_addr_t)page_nr << PAGE_SHIFT) | +- check_pgprot(pgprot)); ++ phys_addr_t pfn = (phys_addr_t)page_nr << PAGE_SHIFT; ++ pfn ^= protnone_mask(pgprot_val(pgprot)); ++ pfn &= PHYSICAL_PMD_PAGE_MASK; ++ return __pmd(pfn | check_pgprot(pgprot)); + } + + static inline pud_t pfn_pud(unsigned long page_nr, pgprot_t pgprot) + { +- return __pud(((phys_addr_t)page_nr << PAGE_SHIFT) | +- check_pgprot(pgprot)); ++ phys_addr_t pfn = (phys_addr_t)page_nr << PAGE_SHIFT; ++ pfn ^= protnone_mask(pgprot_val(pgprot)); ++ pfn &= PHYSICAL_PUD_PAGE_MASK; ++ return __pud(pfn | check_pgprot(pgprot)); + } + ++static inline pmd_t pmd_mknotpresent(pmd_t pmd) ++{ ++ return pfn_pmd(pmd_pfn(pmd), ++ __pgprot(pmd_flags(pmd) & ~(_PAGE_PRESENT|_PAGE_PROTNONE))); ++} ++ ++static inline pud_t pud_mknotpresent(pud_t pud) ++{ ++ return pfn_pud(pud_pfn(pud), ++ __pgprot(pud_flags(pud) & ~(_PAGE_PRESENT|_PAGE_PROTNONE))); ++} ++ ++static inline u64 flip_protnone_guard(u64 oldval, u64 val, u64 mask); ++ + static inline pte_t pte_modify(pte_t pte, pgprot_t newprot) + { +- pteval_t val = pte_val(pte); ++ pteval_t val = pte_val(pte), oldval = val; + + /* + * Chop off the NX bit (if present), and add the NX portion of +@@ -571,17 +591,17 @@ static inline pte_t pte_modify(pte_t pte, pgprot_t newprot) + */ + val &= _PAGE_CHG_MASK; + val |= check_pgprot(newprot) & ~_PAGE_CHG_MASK; +- ++ val = flip_protnone_guard(oldval, val, PTE_PFN_MASK); + return __pte(val); + } + + static inline pmd_t pmd_modify(pmd_t pmd, pgprot_t newprot) + { +- pmdval_t val = pmd_val(pmd); ++ pmdval_t val = pmd_val(pmd), oldval = val; + + val &= _HPAGE_CHG_MASK; + val |= check_pgprot(newprot) & ~_HPAGE_CHG_MASK; +- ++ val = flip_protnone_guard(oldval, val, PHYSICAL_PMD_PAGE_MASK); + return __pmd(val); + } + +@@ -1320,6 +1340,14 @@ static inline bool pud_access_permitted(pud_t pud, bool write) + return __pte_access_permitted(pud_val(pud), write); + } + ++#define __HAVE_ARCH_PFN_MODIFY_ALLOWED 1 ++extern bool pfn_modify_allowed(unsigned long pfn, pgprot_t prot); ++ ++static inline bool arch_has_pfn_modify_check(void) ++{ ++ return boot_cpu_has_bug(X86_BUG_L1TF); ++} ++ + #include + #endif /* __ASSEMBLY__ */ + +diff --git a/arch/x86/include/asm/pgtable_64.h b/arch/x86/include/asm/pgtable_64.h +index 3c5385f9a88f..82ff20b0ae45 100644 +--- a/arch/x86/include/asm/pgtable_64.h ++++ b/arch/x86/include/asm/pgtable_64.h +@@ -273,7 +273,7 @@ static inline int pgd_large(pgd_t pgd) { return 0; } + * + * | ... | 11| 10| 9|8|7|6|5| 4| 3|2| 1|0| <- bit number + * | ... |SW3|SW2|SW1|G|L|D|A|CD|WT|U| W|P| <- bit names +- * | OFFSET (14->63) | TYPE (9-13) |0|0|X|X| X| X|X|SD|0| <- swp entry ++ * | TYPE (59-63) | ~OFFSET (9-58) |0|0|X|X| X| X|X|SD|0| <- swp entry + * + * G (8) is aliased and used as a PROT_NONE indicator for + * !present ptes. We need to start storing swap entries above +@@ -286,20 +286,34 @@ static inline int pgd_large(pgd_t pgd) { return 0; } + * + * Bit 7 in swp entry should be 0 because pmd_present checks not only P, + * but also L and G. ++ * ++ * The offset is inverted by a binary not operation to make the high ++ * physical bits set. + */ +-#define SWP_TYPE_FIRST_BIT (_PAGE_BIT_PROTNONE + 1) +-#define SWP_TYPE_BITS 5 +-/* Place the offset above the type: */ +-#define SWP_OFFSET_FIRST_BIT (SWP_TYPE_FIRST_BIT + SWP_TYPE_BITS) ++#define SWP_TYPE_BITS 5 ++ ++#define SWP_OFFSET_FIRST_BIT (_PAGE_BIT_PROTNONE + 1) ++ ++/* We always extract/encode the offset by shifting it all the way up, and then down again */ ++#define SWP_OFFSET_SHIFT (SWP_OFFSET_FIRST_BIT+SWP_TYPE_BITS) + + #define MAX_SWAPFILES_CHECK() BUILD_BUG_ON(MAX_SWAPFILES_SHIFT > SWP_TYPE_BITS) + +-#define __swp_type(x) (((x).val >> (SWP_TYPE_FIRST_BIT)) \ +- & ((1U << SWP_TYPE_BITS) - 1)) +-#define __swp_offset(x) ((x).val >> SWP_OFFSET_FIRST_BIT) +-#define __swp_entry(type, offset) ((swp_entry_t) { \ +- ((type) << (SWP_TYPE_FIRST_BIT)) \ +- | ((offset) << SWP_OFFSET_FIRST_BIT) }) ++/* Extract the high bits for type */ ++#define __swp_type(x) ((x).val >> (64 - SWP_TYPE_BITS)) ++ ++/* Shift up (to get rid of type), then down to get value */ ++#define __swp_offset(x) (~(x).val << SWP_TYPE_BITS >> SWP_OFFSET_SHIFT) ++ ++/* ++ * Shift the offset up "too far" by TYPE bits, then down again ++ * The offset is inverted by a binary not operation to make the high ++ * physical bits set. ++ */ ++#define __swp_entry(type, offset) ((swp_entry_t) { \ ++ (~(unsigned long)(offset) << SWP_OFFSET_SHIFT >> SWP_TYPE_BITS) \ ++ | ((unsigned long)(type) << (64-SWP_TYPE_BITS)) }) ++ + #define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val((pte)) }) + #define __pmd_to_swp_entry(pmd) ((swp_entry_t) { pmd_val((pmd)) }) + #define __swp_entry_to_pte(x) ((pte_t) { .pte = (x).val }) +@@ -343,5 +357,7 @@ static inline bool gup_fast_permitted(unsigned long start, int nr_pages, + return true; + } + ++#include ++ + #endif /* !__ASSEMBLY__ */ + #endif /* _ASM_X86_PGTABLE_64_H */ +diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h +index cfd29ee8c3da..79e409974ccc 100644 +--- a/arch/x86/include/asm/processor.h ++++ b/arch/x86/include/asm/processor.h +@@ -181,6 +181,11 @@ extern const struct seq_operations cpuinfo_op; + + extern void cpu_detect(struct cpuinfo_x86 *c); + ++static inline unsigned long l1tf_pfn_limit(void) ++{ ++ return BIT(boot_cpu_data.x86_phys_bits - 1 - PAGE_SHIFT) - 1; ++} ++ + extern void early_cpu_init(void); + extern void identify_boot_cpu(void); + extern void identify_secondary_cpu(struct cpuinfo_x86 *); +@@ -977,4 +982,16 @@ bool xen_set_default_idle(void); + void stop_this_cpu(void *dummy); + void df_debug(struct pt_regs *regs, long error_code); + void microcode_check(void); ++ ++enum l1tf_mitigations { ++ L1TF_MITIGATION_OFF, ++ L1TF_MITIGATION_FLUSH_NOWARN, ++ L1TF_MITIGATION_FLUSH, ++ L1TF_MITIGATION_FLUSH_NOSMT, ++ L1TF_MITIGATION_FULL, ++ L1TF_MITIGATION_FULL_FORCE ++}; ++ ++extern enum l1tf_mitigations l1tf_mitigation; ++ + #endif /* _ASM_X86_PROCESSOR_H */ +diff --git a/arch/x86/include/asm/topology.h b/arch/x86/include/asm/topology.h +index c1d2a9892352..453cf38a1c33 100644 +--- a/arch/x86/include/asm/topology.h ++++ b/arch/x86/include/asm/topology.h +@@ -123,13 +123,17 @@ static inline int topology_max_smt_threads(void) + } + + int topology_update_package_map(unsigned int apicid, unsigned int cpu); +-extern int topology_phys_to_logical_pkg(unsigned int pkg); ++int topology_phys_to_logical_pkg(unsigned int pkg); ++bool topology_is_primary_thread(unsigned int cpu); ++bool topology_smt_supported(void); + #else + #define topology_max_packages() (1) + static inline int + topology_update_package_map(unsigned int apicid, unsigned int cpu) { return 0; } + static inline int topology_phys_to_logical_pkg(unsigned int pkg) { return 0; } + static inline int topology_max_smt_threads(void) { return 1; } ++static inline bool topology_is_primary_thread(unsigned int cpu) { return true; } ++static inline bool topology_smt_supported(void) { return false; } + #endif + + static inline void arch_fix_phys_package_id(int num, u32 slot) +diff --git a/arch/x86/include/asm/vmx.h b/arch/x86/include/asm/vmx.h +index 6aa8499e1f62..95f9107449bf 100644 +--- a/arch/x86/include/asm/vmx.h ++++ b/arch/x86/include/asm/vmx.h +@@ -576,4 +576,15 @@ enum vm_instruction_error_number { + VMXERR_INVALID_OPERAND_TO_INVEPT_INVVPID = 28, + }; + ++enum vmx_l1d_flush_state { ++ VMENTER_L1D_FLUSH_AUTO, ++ VMENTER_L1D_FLUSH_NEVER, ++ VMENTER_L1D_FLUSH_COND, ++ VMENTER_L1D_FLUSH_ALWAYS, ++ VMENTER_L1D_FLUSH_EPT_DISABLED, ++ VMENTER_L1D_FLUSH_NOT_REQUIRED, ++}; ++ ++extern enum vmx_l1d_flush_state l1tf_vmx_mitigation; ++ + #endif +diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c +index adbda5847b14..3b3a2d0af78d 100644 +--- a/arch/x86/kernel/apic/apic.c ++++ b/arch/x86/kernel/apic/apic.c +@@ -56,6 +56,7 @@ + #include + #include + #include ++#include + + unsigned int num_processors; + +@@ -2192,6 +2193,23 @@ static int cpuid_to_apicid[] = { + [0 ... NR_CPUS - 1] = -1, + }; + ++#ifdef CONFIG_SMP ++/** ++ * apic_id_is_primary_thread - Check whether APIC ID belongs to a primary thread ++ * @id: APIC ID to check ++ */ ++bool apic_id_is_primary_thread(unsigned int apicid) ++{ ++ u32 mask; ++ ++ if (smp_num_siblings == 1) ++ return true; ++ /* Isolate the SMT bit(s) in the APICID and check for 0 */ ++ mask = (1U << (fls(smp_num_siblings) - 1)) - 1; ++ return !(apicid & mask); ++} ++#endif ++ + /* + * Should use this API to allocate logical CPU IDs to keep nr_logical_cpuids + * and cpuid_to_apicid[] synchronized. +diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c +index 3982f79d2377..ff0d14cd9e82 100644 +--- a/arch/x86/kernel/apic/io_apic.c ++++ b/arch/x86/kernel/apic/io_apic.c +@@ -33,6 +33,7 @@ + + #include + #include ++#include + #include + #include + #include +diff --git a/arch/x86/kernel/apic/msi.c b/arch/x86/kernel/apic/msi.c +index ce503c99f5c4..72a94401f9e0 100644 +--- a/arch/x86/kernel/apic/msi.c ++++ b/arch/x86/kernel/apic/msi.c +@@ -12,6 +12,7 @@ + */ + #include + #include ++#include + #include + #include + #include +diff --git a/arch/x86/kernel/apic/vector.c b/arch/x86/kernel/apic/vector.c +index 35aaee4fc028..c9b773401fd8 100644 +--- a/arch/x86/kernel/apic/vector.c ++++ b/arch/x86/kernel/apic/vector.c +@@ -11,6 +11,7 @@ + * published by the Free Software Foundation. + */ + #include ++#include + #include + #include + #include +diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c +index 38915fbfae73..97e962afb967 100644 +--- a/arch/x86/kernel/cpu/amd.c ++++ b/arch/x86/kernel/cpu/amd.c +@@ -315,6 +315,13 @@ static void legacy_fixup_core_id(struct cpuinfo_x86 *c) + c->cpu_core_id %= cus_per_node; + } + ++ ++static void amd_get_topology_early(struct cpuinfo_x86 *c) ++{ ++ if (cpu_has(c, X86_FEATURE_TOPOEXT)) ++ smp_num_siblings = ((cpuid_ebx(0x8000001e) >> 8) & 0xff) + 1; ++} ++ + /* + * Fixup core topology information for + * (1) AMD multi-node processors +@@ -334,7 +341,6 @@ static void amd_get_topology(struct cpuinfo_x86 *c) + cpuid(0x8000001e, &eax, &ebx, &ecx, &edx); + + node_id = ecx & 0xff; +- smp_num_siblings = ((ebx >> 8) & 0xff) + 1; + + if (c->x86 == 0x15) + c->cu_id = ebx & 0xff; +@@ -613,6 +619,7 @@ clear_sev: + + static void early_init_amd(struct cpuinfo_x86 *c) + { ++ u64 value; + u32 dummy; + + early_init_amd_mc(c); +@@ -683,6 +690,22 @@ static void early_init_amd(struct cpuinfo_x86 *c) + set_cpu_bug(c, X86_BUG_AMD_E400); + + early_detect_mem_encrypt(c); ++ ++ /* Re-enable TopologyExtensions if switched off by BIOS */ ++ if (c->x86 == 0x15 && ++ (c->x86_model >= 0x10 && c->x86_model <= 0x6f) && ++ !cpu_has(c, X86_FEATURE_TOPOEXT)) { ++ ++ if (msr_set_bit(0xc0011005, 54) > 0) { ++ rdmsrl(0xc0011005, value); ++ if (value & BIT_64(54)) { ++ set_cpu_cap(c, X86_FEATURE_TOPOEXT); ++ pr_info_once(FW_INFO "CPU: Re-enabling disabled Topology Extensions Support.\n"); ++ } ++ } ++ } ++ ++ amd_get_topology_early(c); + } + + static void init_amd_k8(struct cpuinfo_x86 *c) +@@ -774,19 +797,6 @@ static void init_amd_bd(struct cpuinfo_x86 *c) + { + u64 value; + +- /* re-enable TopologyExtensions if switched off by BIOS */ +- if ((c->x86_model >= 0x10) && (c->x86_model <= 0x6f) && +- !cpu_has(c, X86_FEATURE_TOPOEXT)) { +- +- if (msr_set_bit(0xc0011005, 54) > 0) { +- rdmsrl(0xc0011005, value); +- if (value & BIT_64(54)) { +- set_cpu_cap(c, X86_FEATURE_TOPOEXT); +- pr_info_once(FW_INFO "CPU: Re-enabling disabled Topology Extensions Support.\n"); +- } +- } +- } +- + /* + * The way access filter has a performance penalty on some workloads. + * Disable it on the affected CPUs. +@@ -850,16 +860,9 @@ static void init_amd(struct cpuinfo_x86 *c) + + cpu_detect_cache_sizes(c); + +- /* Multi core CPU? */ +- if (c->extended_cpuid_level >= 0x80000008) { +- amd_detect_cmp(c); +- amd_get_topology(c); +- srat_detect_node(c); +- } +- +-#ifdef CONFIG_X86_32 +- detect_ht(c); +-#endif ++ amd_detect_cmp(c); ++ amd_get_topology(c); ++ srat_detect_node(c); + + init_amd_cacheinfo(c); + +diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c +index 5c0ea39311fe..c4f0ae49a53d 100644 +--- a/arch/x86/kernel/cpu/bugs.c ++++ b/arch/x86/kernel/cpu/bugs.c +@@ -22,15 +22,18 @@ + #include + #include + #include ++#include + #include + #include + #include + #include + #include + #include ++#include + + static void __init spectre_v2_select_mitigation(void); + static void __init ssb_select_mitigation(void); ++static void __init l1tf_select_mitigation(void); + + /* + * Our boot-time value of the SPEC_CTRL MSR. We read it once so that any +@@ -56,6 +59,12 @@ void __init check_bugs(void) + { + identify_boot_cpu(); + ++ /* ++ * identify_boot_cpu() initialized SMT support information, let the ++ * core code know. ++ */ ++ cpu_smt_check_topology_early(); ++ + if (!IS_ENABLED(CONFIG_SMP)) { + pr_info("CPU: "); + print_cpu_info(&boot_cpu_data); +@@ -82,6 +91,8 @@ void __init check_bugs(void) + */ + ssb_select_mitigation(); + ++ l1tf_select_mitigation(); ++ + #ifdef CONFIG_X86_32 + /* + * Check whether we are able to run this kernel safely on SMP. +@@ -313,23 +324,6 @@ static enum spectre_v2_mitigation_cmd __init spectre_v2_parse_cmdline(void) + return cmd; + } + +-/* Check for Skylake-like CPUs (for RSB handling) */ +-static bool __init is_skylake_era(void) +-{ +- if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL && +- boot_cpu_data.x86 == 6) { +- switch (boot_cpu_data.x86_model) { +- case INTEL_FAM6_SKYLAKE_MOBILE: +- case INTEL_FAM6_SKYLAKE_DESKTOP: +- case INTEL_FAM6_SKYLAKE_X: +- case INTEL_FAM6_KABYLAKE_MOBILE: +- case INTEL_FAM6_KABYLAKE_DESKTOP: +- return true; +- } +- } +- return false; +-} +- + static void __init spectre_v2_select_mitigation(void) + { + enum spectre_v2_mitigation_cmd cmd = spectre_v2_parse_cmdline(); +@@ -390,22 +384,15 @@ retpoline_auto: + pr_info("%s\n", spectre_v2_strings[mode]); + + /* +- * If neither SMEP nor PTI are available, there is a risk of +- * hitting userspace addresses in the RSB after a context switch +- * from a shallow call stack to a deeper one. To prevent this fill +- * the entire RSB, even when using IBRS. ++ * If spectre v2 protection has been enabled, unconditionally fill ++ * RSB during a context switch; this protects against two independent ++ * issues: + * +- * Skylake era CPUs have a separate issue with *underflow* of the +- * RSB, when they will predict 'ret' targets from the generic BTB. +- * The proper mitigation for this is IBRS. If IBRS is not supported +- * or deactivated in favour of retpolines the RSB fill on context +- * switch is required. ++ * - RSB underflow (and switch to BTB) on Skylake+ ++ * - SpectreRSB variant of spectre v2 on X86_BUG_SPECTRE_V2 CPUs + */ +- if ((!boot_cpu_has(X86_FEATURE_PTI) && +- !boot_cpu_has(X86_FEATURE_SMEP)) || is_skylake_era()) { +- setup_force_cpu_cap(X86_FEATURE_RSB_CTXSW); +- pr_info("Spectre v2 mitigation: Filling RSB on context switch\n"); +- } ++ setup_force_cpu_cap(X86_FEATURE_RSB_CTXSW); ++ pr_info("Spectre v2 / SpectreRSB mitigation: Filling RSB on context switch\n"); + + /* Initialize Indirect Branch Prediction Barrier if supported */ + if (boot_cpu_has(X86_FEATURE_IBPB)) { +@@ -654,8 +641,121 @@ void x86_spec_ctrl_setup_ap(void) + x86_amd_ssb_disable(); + } + ++#undef pr_fmt ++#define pr_fmt(fmt) "L1TF: " fmt ++ ++/* Default mitigation for L1TF-affected CPUs */ ++enum l1tf_mitigations l1tf_mitigation __ro_after_init = L1TF_MITIGATION_FLUSH; ++#if IS_ENABLED(CONFIG_KVM_INTEL) ++EXPORT_SYMBOL_GPL(l1tf_mitigation); ++ ++enum vmx_l1d_flush_state l1tf_vmx_mitigation = VMENTER_L1D_FLUSH_AUTO; ++EXPORT_SYMBOL_GPL(l1tf_vmx_mitigation); ++#endif ++ ++static void __init l1tf_select_mitigation(void) ++{ ++ u64 half_pa; ++ ++ if (!boot_cpu_has_bug(X86_BUG_L1TF)) ++ return; ++ ++ switch (l1tf_mitigation) { ++ case L1TF_MITIGATION_OFF: ++ case L1TF_MITIGATION_FLUSH_NOWARN: ++ case L1TF_MITIGATION_FLUSH: ++ break; ++ case L1TF_MITIGATION_FLUSH_NOSMT: ++ case L1TF_MITIGATION_FULL: ++ cpu_smt_disable(false); ++ break; ++ case L1TF_MITIGATION_FULL_FORCE: ++ cpu_smt_disable(true); ++ break; ++ } ++ ++#if CONFIG_PGTABLE_LEVELS == 2 ++ pr_warn("Kernel not compiled for PAE. No mitigation for L1TF\n"); ++ return; ++#endif ++ ++ /* ++ * This is extremely unlikely to happen because almost all ++ * systems have far more MAX_PA/2 than RAM can be fit into ++ * DIMM slots. ++ */ ++ half_pa = (u64)l1tf_pfn_limit() << PAGE_SHIFT; ++ if (e820__mapped_any(half_pa, ULLONG_MAX - half_pa, E820_TYPE_RAM)) { ++ pr_warn("System has more than MAX_PA/2 memory. L1TF mitigation not effective.\n"); ++ return; ++ } ++ ++ setup_force_cpu_cap(X86_FEATURE_L1TF_PTEINV); ++} ++ ++static int __init l1tf_cmdline(char *str) ++{ ++ if (!boot_cpu_has_bug(X86_BUG_L1TF)) ++ return 0; ++ ++ if (!str) ++ return -EINVAL; ++ ++ if (!strcmp(str, "off")) ++ l1tf_mitigation = L1TF_MITIGATION_OFF; ++ else if (!strcmp(str, "flush,nowarn")) ++ l1tf_mitigation = L1TF_MITIGATION_FLUSH_NOWARN; ++ else if (!strcmp(str, "flush")) ++ l1tf_mitigation = L1TF_MITIGATION_FLUSH; ++ else if (!strcmp(str, "flush,nosmt")) ++ l1tf_mitigation = L1TF_MITIGATION_FLUSH_NOSMT; ++ else if (!strcmp(str, "full")) ++ l1tf_mitigation = L1TF_MITIGATION_FULL; ++ else if (!strcmp(str, "full,force")) ++ l1tf_mitigation = L1TF_MITIGATION_FULL_FORCE; ++ ++ return 0; ++} ++early_param("l1tf", l1tf_cmdline); ++ ++#undef pr_fmt ++ + #ifdef CONFIG_SYSFS + ++#define L1TF_DEFAULT_MSG "Mitigation: PTE Inversion" ++ ++#if IS_ENABLED(CONFIG_KVM_INTEL) ++static const char *l1tf_vmx_states[] = { ++ [VMENTER_L1D_FLUSH_AUTO] = "auto", ++ [VMENTER_L1D_FLUSH_NEVER] = "vulnerable", ++ [VMENTER_L1D_FLUSH_COND] = "conditional cache flushes", ++ [VMENTER_L1D_FLUSH_ALWAYS] = "cache flushes", ++ [VMENTER_L1D_FLUSH_EPT_DISABLED] = "EPT disabled", ++ [VMENTER_L1D_FLUSH_NOT_REQUIRED] = "flush not necessary" ++}; ++ ++static ssize_t l1tf_show_state(char *buf) ++{ ++ if (l1tf_vmx_mitigation == VMENTER_L1D_FLUSH_AUTO) ++ return sprintf(buf, "%s\n", L1TF_DEFAULT_MSG); ++ ++ if (l1tf_vmx_mitigation == VMENTER_L1D_FLUSH_EPT_DISABLED || ++ (l1tf_vmx_mitigation == VMENTER_L1D_FLUSH_NEVER && ++ cpu_smt_control == CPU_SMT_ENABLED)) ++ return sprintf(buf, "%s; VMX: %s\n", L1TF_DEFAULT_MSG, ++ l1tf_vmx_states[l1tf_vmx_mitigation]); ++ ++ return sprintf(buf, "%s; VMX: %s, SMT %s\n", L1TF_DEFAULT_MSG, ++ l1tf_vmx_states[l1tf_vmx_mitigation], ++ cpu_smt_control == CPU_SMT_ENABLED ? "vulnerable" : "disabled"); ++} ++#else ++static ssize_t l1tf_show_state(char *buf) ++{ ++ return sprintf(buf, "%s\n", L1TF_DEFAULT_MSG); ++} ++#endif ++ + static ssize_t cpu_show_common(struct device *dev, struct device_attribute *attr, + char *buf, unsigned int bug) + { +@@ -684,6 +784,10 @@ static ssize_t cpu_show_common(struct device *dev, struct device_attribute *attr + case X86_BUG_SPEC_STORE_BYPASS: + return sprintf(buf, "%s\n", ssb_strings[ssb_mode]); + ++ case X86_BUG_L1TF: ++ if (boot_cpu_has(X86_FEATURE_L1TF_PTEINV)) ++ return l1tf_show_state(buf); ++ break; + default: + break; + } +@@ -710,4 +814,9 @@ ssize_t cpu_show_spec_store_bypass(struct device *dev, struct device_attribute * + { + return cpu_show_common(dev, attr, buf, X86_BUG_SPEC_STORE_BYPASS); + } ++ ++ssize_t cpu_show_l1tf(struct device *dev, struct device_attribute *attr, char *buf) ++{ ++ return cpu_show_common(dev, attr, buf, X86_BUG_L1TF); ++} + #endif +diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c +index eb4cb3efd20e..9eda6f730ec4 100644 +--- a/arch/x86/kernel/cpu/common.c ++++ b/arch/x86/kernel/cpu/common.c +@@ -661,33 +661,36 @@ static void cpu_detect_tlb(struct cpuinfo_x86 *c) + tlb_lld_4m[ENTRIES], tlb_lld_1g[ENTRIES]); + } + +-void detect_ht(struct cpuinfo_x86 *c) ++int detect_ht_early(struct cpuinfo_x86 *c) + { + #ifdef CONFIG_SMP + u32 eax, ebx, ecx, edx; +- int index_msb, core_bits; +- static bool printed; + + if (!cpu_has(c, X86_FEATURE_HT)) +- return; ++ return -1; + + if (cpu_has(c, X86_FEATURE_CMP_LEGACY)) +- goto out; ++ return -1; + + if (cpu_has(c, X86_FEATURE_XTOPOLOGY)) +- return; ++ return -1; + + cpuid(1, &eax, &ebx, &ecx, &edx); + + smp_num_siblings = (ebx & 0xff0000) >> 16; +- +- if (smp_num_siblings == 1) { ++ if (smp_num_siblings == 1) + pr_info_once("CPU0: Hyper-Threading is disabled\n"); +- goto out; +- } ++#endif ++ return 0; ++} + +- if (smp_num_siblings <= 1) +- goto out; ++void detect_ht(struct cpuinfo_x86 *c) ++{ ++#ifdef CONFIG_SMP ++ int index_msb, core_bits; ++ ++ if (detect_ht_early(c) < 0) ++ return; + + index_msb = get_count_order(smp_num_siblings); + c->phys_proc_id = apic->phys_pkg_id(c->initial_apicid, index_msb); +@@ -700,15 +703,6 @@ void detect_ht(struct cpuinfo_x86 *c) + + c->cpu_core_id = apic->phys_pkg_id(c->initial_apicid, index_msb) & + ((1 << core_bits) - 1); +- +-out: +- if (!printed && (c->x86_max_cores * smp_num_siblings) > 1) { +- pr_info("CPU: Physical Processor ID: %d\n", +- c->phys_proc_id); +- pr_info("CPU: Processor Core ID: %d\n", +- c->cpu_core_id); +- printed = 1; +- } + #endif + } + +@@ -987,6 +981,21 @@ static const __initconst struct x86_cpu_id cpu_no_spec_store_bypass[] = { + {} + }; + ++static const __initconst struct x86_cpu_id cpu_no_l1tf[] = { ++ /* in addition to cpu_no_speculation */ ++ { X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_SILVERMONT1 }, ++ { X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_SILVERMONT2 }, ++ { X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_AIRMONT }, ++ { X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_MERRIFIELD }, ++ { X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_MOOREFIELD }, ++ { X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_GOLDMONT }, ++ { X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_DENVERTON }, ++ { X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_GEMINI_LAKE }, ++ { X86_VENDOR_INTEL, 6, INTEL_FAM6_XEON_PHI_KNL }, ++ { X86_VENDOR_INTEL, 6, INTEL_FAM6_XEON_PHI_KNM }, ++ {} ++}; ++ + static void __init cpu_set_bug_bits(struct cpuinfo_x86 *c) + { + u64 ia32_cap = 0; +@@ -1013,6 +1022,11 @@ static void __init cpu_set_bug_bits(struct cpuinfo_x86 *c) + return; + + setup_force_cpu_bug(X86_BUG_CPU_MELTDOWN); ++ ++ if (x86_match_cpu(cpu_no_l1tf)) ++ return; ++ ++ setup_force_cpu_bug(X86_BUG_L1TF); + } + + /* +diff --git a/arch/x86/kernel/cpu/cpu.h b/arch/x86/kernel/cpu/cpu.h +index 38216f678fc3..e59c0ea82a33 100644 +--- a/arch/x86/kernel/cpu/cpu.h ++++ b/arch/x86/kernel/cpu/cpu.h +@@ -55,7 +55,9 @@ extern void init_intel_cacheinfo(struct cpuinfo_x86 *c); + extern void init_amd_cacheinfo(struct cpuinfo_x86 *c); + + extern void detect_num_cpu_cores(struct cpuinfo_x86 *c); ++extern int detect_extended_topology_early(struct cpuinfo_x86 *c); + extern int detect_extended_topology(struct cpuinfo_x86 *c); ++extern int detect_ht_early(struct cpuinfo_x86 *c); + extern void detect_ht(struct cpuinfo_x86 *c); + + unsigned int aperfmperf_get_khz(int cpu); +diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c +index eb75564f2d25..6602941cfebf 100644 +--- a/arch/x86/kernel/cpu/intel.c ++++ b/arch/x86/kernel/cpu/intel.c +@@ -301,6 +301,13 @@ static void early_init_intel(struct cpuinfo_x86 *c) + } + + check_mpx_erratum(c); ++ ++ /* ++ * Get the number of SMT siblings early from the extended topology ++ * leaf, if available. Otherwise try the legacy SMT detection. ++ */ ++ if (detect_extended_topology_early(c) < 0) ++ detect_ht_early(c); + } + + #ifdef CONFIG_X86_32 +diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c +index 08286269fd24..b9bc8a1a584e 100644 +--- a/arch/x86/kernel/cpu/microcode/core.c ++++ b/arch/x86/kernel/cpu/microcode/core.c +@@ -509,12 +509,20 @@ static struct platform_device *microcode_pdev; + + static int check_online_cpus(void) + { +- if (num_online_cpus() == num_present_cpus()) +- return 0; ++ unsigned int cpu; + +- pr_err("Not all CPUs online, aborting microcode update.\n"); ++ /* ++ * Make sure all CPUs are online. It's fine for SMT to be disabled if ++ * all the primary threads are still online. ++ */ ++ for_each_present_cpu(cpu) { ++ if (topology_is_primary_thread(cpu) && !cpu_online(cpu)) { ++ pr_err("Not all CPUs online, aborting microcode update.\n"); ++ return -EINVAL; ++ } ++ } + +- return -EINVAL; ++ return 0; + } + + static atomic_t late_cpus_in; +diff --git a/arch/x86/kernel/cpu/topology.c b/arch/x86/kernel/cpu/topology.c +index 81c0afb39d0a..71ca064e3794 100644 +--- a/arch/x86/kernel/cpu/topology.c ++++ b/arch/x86/kernel/cpu/topology.c +@@ -22,18 +22,10 @@ + #define BITS_SHIFT_NEXT_LEVEL(eax) ((eax) & 0x1f) + #define LEVEL_MAX_SIBLINGS(ebx) ((ebx) & 0xffff) + +-/* +- * Check for extended topology enumeration cpuid leaf 0xb and if it +- * exists, use it for populating initial_apicid and cpu topology +- * detection. +- */ +-int detect_extended_topology(struct cpuinfo_x86 *c) ++int detect_extended_topology_early(struct cpuinfo_x86 *c) + { + #ifdef CONFIG_SMP +- unsigned int eax, ebx, ecx, edx, sub_index; +- unsigned int ht_mask_width, core_plus_mask_width; +- unsigned int core_select_mask, core_level_siblings; +- static bool printed; ++ unsigned int eax, ebx, ecx, edx; + + if (c->cpuid_level < 0xb) + return -1; +@@ -52,10 +44,30 @@ int detect_extended_topology(struct cpuinfo_x86 *c) + * initial apic id, which also represents 32-bit extended x2apic id. + */ + c->initial_apicid = edx; ++ smp_num_siblings = LEVEL_MAX_SIBLINGS(ebx); ++#endif ++ return 0; ++} ++ ++/* ++ * Check for extended topology enumeration cpuid leaf 0xb and if it ++ * exists, use it for populating initial_apicid and cpu topology ++ * detection. ++ */ ++int detect_extended_topology(struct cpuinfo_x86 *c) ++{ ++#ifdef CONFIG_SMP ++ unsigned int eax, ebx, ecx, edx, sub_index; ++ unsigned int ht_mask_width, core_plus_mask_width; ++ unsigned int core_select_mask, core_level_siblings; ++ ++ if (detect_extended_topology_early(c) < 0) ++ return -1; + + /* + * Populate HT related information from sub-leaf level 0. + */ ++ cpuid_count(0xb, SMT_LEVEL, &eax, &ebx, &ecx, &edx); + core_level_siblings = smp_num_siblings = LEVEL_MAX_SIBLINGS(ebx); + core_plus_mask_width = ht_mask_width = BITS_SHIFT_NEXT_LEVEL(eax); + +@@ -86,15 +98,6 @@ int detect_extended_topology(struct cpuinfo_x86 *c) + c->apicid = apic->phys_pkg_id(c->initial_apicid, 0); + + c->x86_max_cores = (core_level_siblings / smp_num_siblings); +- +- if (!printed) { +- pr_info("CPU: Physical Processor ID: %d\n", +- c->phys_proc_id); +- if (c->x86_max_cores > 1) +- pr_info("CPU: Processor Core ID: %d\n", +- c->cpu_core_id); +- printed = 1; +- } + #endif + return 0; + } +diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c +index f92a6593de1e..2ea85b32421a 100644 +--- a/arch/x86/kernel/fpu/core.c ++++ b/arch/x86/kernel/fpu/core.c +@@ -10,6 +10,7 @@ + #include + #include + #include ++#include + + #include + #include +diff --git a/arch/x86/kernel/hpet.c b/arch/x86/kernel/hpet.c +index 346b24883911..b0acb22e5a46 100644 +--- a/arch/x86/kernel/hpet.c ++++ b/arch/x86/kernel/hpet.c +@@ -1,6 +1,7 @@ + #include + #include + #include ++#include + #include + #include + #include +diff --git a/arch/x86/kernel/i8259.c b/arch/x86/kernel/i8259.c +index 86c4439f9d74..519649ddf100 100644 +--- a/arch/x86/kernel/i8259.c ++++ b/arch/x86/kernel/i8259.c +@@ -5,6 +5,7 @@ + #include + #include + #include ++#include + #include + #include + #include +diff --git a/arch/x86/kernel/idt.c b/arch/x86/kernel/idt.c +index 74383a3780dc..01adea278a71 100644 +--- a/arch/x86/kernel/idt.c ++++ b/arch/x86/kernel/idt.c +@@ -8,6 +8,7 @@ + #include + #include + #include ++#include + + struct idt_data { + unsigned int vector; +diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c +index 328d027d829d..59b5f2ea7c2f 100644 +--- a/arch/x86/kernel/irq.c ++++ b/arch/x86/kernel/irq.c +@@ -10,6 +10,7 @@ + #include + #include + #include ++#include + + #include + #include +diff --git a/arch/x86/kernel/irq_32.c b/arch/x86/kernel/irq_32.c +index c1bdbd3d3232..95600a99ae93 100644 +--- a/arch/x86/kernel/irq_32.c ++++ b/arch/x86/kernel/irq_32.c +@@ -11,6 +11,7 @@ + + #include + #include ++#include + #include + #include + #include +diff --git a/arch/x86/kernel/irq_64.c b/arch/x86/kernel/irq_64.c +index d86e344f5b3d..0469cd078db1 100644 +--- a/arch/x86/kernel/irq_64.c ++++ b/arch/x86/kernel/irq_64.c +@@ -11,6 +11,7 @@ + + #include + #include ++#include + #include + #include + #include +diff --git a/arch/x86/kernel/irqinit.c b/arch/x86/kernel/irqinit.c +index 772196c1b8c4..a0693b71cfc1 100644 +--- a/arch/x86/kernel/irqinit.c ++++ b/arch/x86/kernel/irqinit.c +@@ -5,6 +5,7 @@ + #include + #include + #include ++#include + #include + #include + #include +diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c +index 6f4d42377fe5..44e26dc326d5 100644 +--- a/arch/x86/kernel/kprobes/core.c ++++ b/arch/x86/kernel/kprobes/core.c +@@ -395,8 +395,6 @@ int __copy_instruction(u8 *dest, u8 *src, u8 *real, struct insn *insn) + - (u8 *) real; + if ((s64) (s32) newdisp != newdisp) { + pr_err("Kprobes error: new displacement does not fit into s32 (%llx)\n", newdisp); +- pr_err("\tSrc: %p, Dest: %p, old disp: %x\n", +- src, real, insn->displacement.value); + return 0; + } + disp = (u8 *) dest + insn_offset_displacement(insn); +@@ -640,8 +638,7 @@ static int reenter_kprobe(struct kprobe *p, struct pt_regs *regs, + * Raise a BUG or we'll continue in an endless reentering loop + * and eventually a stack overflow. + */ +- printk(KERN_WARNING "Unrecoverable kprobe detected at %p.\n", +- p->addr); ++ pr_err("Unrecoverable kprobe detected.\n"); + dump_kprobe(p); + BUG(); + default: +diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c +index 99dc79e76bdc..930c88341e4e 100644 +--- a/arch/x86/kernel/paravirt.c ++++ b/arch/x86/kernel/paravirt.c +@@ -88,10 +88,12 @@ unsigned paravirt_patch_call(void *insnbuf, + struct branch *b = insnbuf; + unsigned long delta = (unsigned long)target - (addr+5); + +- if (tgt_clobbers & ~site_clobbers) +- return len; /* target would clobber too much for this site */ +- if (len < 5) ++ if (len < 5) { ++#ifdef CONFIG_RETPOLINE ++ WARN_ONCE("Failing to patch indirect CALL in %ps\n", (void *)addr); ++#endif + return len; /* call too long for patch site */ ++ } + + b->opcode = 0xe8; /* call */ + b->delta = delta; +@@ -106,8 +108,12 @@ unsigned paravirt_patch_jmp(void *insnbuf, const void *target, + struct branch *b = insnbuf; + unsigned long delta = (unsigned long)target - (addr+5); + +- if (len < 5) ++ if (len < 5) { ++#ifdef CONFIG_RETPOLINE ++ WARN_ONCE("Failing to patch indirect JMP in %ps\n", (void *)addr); ++#endif + return len; /* call too long for patch site */ ++ } + + b->opcode = 0xe9; /* jmp */ + b->delta = delta; +diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c +index 2f86d883dd95..74b4472ba0a6 100644 +--- a/arch/x86/kernel/setup.c ++++ b/arch/x86/kernel/setup.c +@@ -823,6 +823,12 @@ void __init setup_arch(char **cmdline_p) + memblock_reserve(__pa_symbol(_text), + (unsigned long)__bss_stop - (unsigned long)_text); + ++ /* ++ * Make sure page 0 is always reserved because on systems with ++ * L1TF its contents can be leaked to user processes. ++ */ ++ memblock_reserve(0, PAGE_SIZE); ++ + early_reserve_initrd(); + + /* +diff --git a/arch/x86/kernel/smp.c b/arch/x86/kernel/smp.c +index 5c574dff4c1a..04adc8d60aed 100644 +--- a/arch/x86/kernel/smp.c ++++ b/arch/x86/kernel/smp.c +@@ -261,6 +261,7 @@ __visible void __irq_entry smp_reschedule_interrupt(struct pt_regs *regs) + { + ack_APIC_irq(); + inc_irq_stat(irq_resched_count); ++ kvm_set_cpu_l1tf_flush_l1d(); + + if (trace_resched_ipi_enabled()) { + /* +diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c +index db9656e13ea0..f02ecaf97904 100644 +--- a/arch/x86/kernel/smpboot.c ++++ b/arch/x86/kernel/smpboot.c +@@ -80,6 +80,7 @@ + #include + #include + #include ++#include + + /* representing HT siblings of each logical CPU */ + DEFINE_PER_CPU_READ_MOSTLY(cpumask_var_t, cpu_sibling_map); +@@ -270,6 +271,23 @@ static void notrace start_secondary(void *unused) + cpu_startup_entry(CPUHP_AP_ONLINE_IDLE); + } + ++/** ++ * topology_is_primary_thread - Check whether CPU is the primary SMT thread ++ * @cpu: CPU to check ++ */ ++bool topology_is_primary_thread(unsigned int cpu) ++{ ++ return apic_id_is_primary_thread(per_cpu(x86_cpu_to_apicid, cpu)); ++} ++ ++/** ++ * topology_smt_supported - Check whether SMT is supported by the CPUs ++ */ ++bool topology_smt_supported(void) ++{ ++ return smp_num_siblings > 1; ++} ++ + /** + * topology_phys_to_logical_pkg - Map a physical package id to a logical + * +diff --git a/arch/x86/kernel/time.c b/arch/x86/kernel/time.c +index 774ebafa97c4..be01328eb755 100644 +--- a/arch/x86/kernel/time.c ++++ b/arch/x86/kernel/time.c +@@ -12,6 +12,7 @@ + + #include + #include ++#include + #include + #include + #include +diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c +index 6b8f11521c41..a44e568363a4 100644 +--- a/arch/x86/kvm/mmu.c ++++ b/arch/x86/kvm/mmu.c +@@ -3840,6 +3840,7 @@ int kvm_handle_page_fault(struct kvm_vcpu *vcpu, u64 error_code, + { + int r = 1; + ++ vcpu->arch.l1tf_flush_l1d = true; + switch (vcpu->arch.apf.host_apf_reason) { + default: + trace_kvm_page_fault(fault_address, error_code); +diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c +index 5d8e317c2b04..46b428c0990e 100644 +--- a/arch/x86/kvm/vmx.c ++++ b/arch/x86/kvm/vmx.c +@@ -188,6 +188,150 @@ module_param(ple_window_max, uint, 0444); + + extern const ulong vmx_return; + ++static DEFINE_STATIC_KEY_FALSE(vmx_l1d_should_flush); ++static DEFINE_STATIC_KEY_FALSE(vmx_l1d_flush_cond); ++static DEFINE_MUTEX(vmx_l1d_flush_mutex); ++ ++/* Storage for pre module init parameter parsing */ ++static enum vmx_l1d_flush_state __read_mostly vmentry_l1d_flush_param = VMENTER_L1D_FLUSH_AUTO; ++ ++static const struct { ++ const char *option; ++ enum vmx_l1d_flush_state cmd; ++} vmentry_l1d_param[] = { ++ {"auto", VMENTER_L1D_FLUSH_AUTO}, ++ {"never", VMENTER_L1D_FLUSH_NEVER}, ++ {"cond", VMENTER_L1D_FLUSH_COND}, ++ {"always", VMENTER_L1D_FLUSH_ALWAYS}, ++}; ++ ++#define L1D_CACHE_ORDER 4 ++static void *vmx_l1d_flush_pages; ++ ++static int vmx_setup_l1d_flush(enum vmx_l1d_flush_state l1tf) ++{ ++ struct page *page; ++ unsigned int i; ++ ++ if (!enable_ept) { ++ l1tf_vmx_mitigation = VMENTER_L1D_FLUSH_EPT_DISABLED; ++ return 0; ++ } ++ ++ if (boot_cpu_has(X86_FEATURE_ARCH_CAPABILITIES)) { ++ u64 msr; ++ ++ rdmsrl(MSR_IA32_ARCH_CAPABILITIES, msr); ++ if (msr & ARCH_CAP_SKIP_VMENTRY_L1DFLUSH) { ++ l1tf_vmx_mitigation = VMENTER_L1D_FLUSH_NOT_REQUIRED; ++ return 0; ++ } ++ } ++ ++ /* If set to auto use the default l1tf mitigation method */ ++ if (l1tf == VMENTER_L1D_FLUSH_AUTO) { ++ switch (l1tf_mitigation) { ++ case L1TF_MITIGATION_OFF: ++ l1tf = VMENTER_L1D_FLUSH_NEVER; ++ break; ++ case L1TF_MITIGATION_FLUSH_NOWARN: ++ case L1TF_MITIGATION_FLUSH: ++ case L1TF_MITIGATION_FLUSH_NOSMT: ++ l1tf = VMENTER_L1D_FLUSH_COND; ++ break; ++ case L1TF_MITIGATION_FULL: ++ case L1TF_MITIGATION_FULL_FORCE: ++ l1tf = VMENTER_L1D_FLUSH_ALWAYS; ++ break; ++ } ++ } else if (l1tf_mitigation == L1TF_MITIGATION_FULL_FORCE) { ++ l1tf = VMENTER_L1D_FLUSH_ALWAYS; ++ } ++ ++ if (l1tf != VMENTER_L1D_FLUSH_NEVER && !vmx_l1d_flush_pages && ++ !boot_cpu_has(X86_FEATURE_FLUSH_L1D)) { ++ page = alloc_pages(GFP_KERNEL, L1D_CACHE_ORDER); ++ if (!page) ++ return -ENOMEM; ++ vmx_l1d_flush_pages = page_address(page); ++ ++ /* ++ * Initialize each page with a different pattern in ++ * order to protect against KSM in the nested ++ * virtualization case. ++ */ ++ for (i = 0; i < 1u << L1D_CACHE_ORDER; ++i) { ++ memset(vmx_l1d_flush_pages + i * PAGE_SIZE, i + 1, ++ PAGE_SIZE); ++ } ++ } ++ ++ l1tf_vmx_mitigation = l1tf; ++ ++ if (l1tf != VMENTER_L1D_FLUSH_NEVER) ++ static_branch_enable(&vmx_l1d_should_flush); ++ else ++ static_branch_disable(&vmx_l1d_should_flush); ++ ++ if (l1tf == VMENTER_L1D_FLUSH_COND) ++ static_branch_enable(&vmx_l1d_flush_cond); ++ else ++ static_branch_disable(&vmx_l1d_flush_cond); ++ return 0; ++} ++ ++static int vmentry_l1d_flush_parse(const char *s) ++{ ++ unsigned int i; ++ ++ if (s) { ++ for (i = 0; i < ARRAY_SIZE(vmentry_l1d_param); i++) { ++ if (sysfs_streq(s, vmentry_l1d_param[i].option)) ++ return vmentry_l1d_param[i].cmd; ++ } ++ } ++ return -EINVAL; ++} ++ ++static int vmentry_l1d_flush_set(const char *s, const struct kernel_param *kp) ++{ ++ int l1tf, ret; ++ ++ if (!boot_cpu_has(X86_BUG_L1TF)) ++ return 0; ++ ++ l1tf = vmentry_l1d_flush_parse(s); ++ if (l1tf < 0) ++ return l1tf; ++ ++ /* ++ * Has vmx_init() run already? If not then this is the pre init ++ * parameter parsing. In that case just store the value and let ++ * vmx_init() do the proper setup after enable_ept has been ++ * established. ++ */ ++ if (l1tf_vmx_mitigation == VMENTER_L1D_FLUSH_AUTO) { ++ vmentry_l1d_flush_param = l1tf; ++ return 0; ++ } ++ ++ mutex_lock(&vmx_l1d_flush_mutex); ++ ret = vmx_setup_l1d_flush(l1tf); ++ mutex_unlock(&vmx_l1d_flush_mutex); ++ return ret; ++} ++ ++static int vmentry_l1d_flush_get(char *s, const struct kernel_param *kp) ++{ ++ return sprintf(s, "%s\n", vmentry_l1d_param[l1tf_vmx_mitigation].option); ++} ++ ++static const struct kernel_param_ops vmentry_l1d_flush_ops = { ++ .set = vmentry_l1d_flush_set, ++ .get = vmentry_l1d_flush_get, ++}; ++module_param_cb(vmentry_l1d_flush, &vmentry_l1d_flush_ops, NULL, 0644); ++ + struct kvm_vmx { + struct kvm kvm; + +@@ -757,6 +901,11 @@ static inline int pi_test_sn(struct pi_desc *pi_desc) + (unsigned long *)&pi_desc->control); + } + ++struct vmx_msrs { ++ unsigned int nr; ++ struct vmx_msr_entry val[NR_AUTOLOAD_MSRS]; ++}; ++ + struct vcpu_vmx { + struct kvm_vcpu vcpu; + unsigned long host_rsp; +@@ -790,9 +939,8 @@ struct vcpu_vmx { + struct loaded_vmcs *loaded_vmcs; + bool __launched; /* temporary, used in vmx_vcpu_run */ + struct msr_autoload { +- unsigned nr; +- struct vmx_msr_entry guest[NR_AUTOLOAD_MSRS]; +- struct vmx_msr_entry host[NR_AUTOLOAD_MSRS]; ++ struct vmx_msrs guest; ++ struct vmx_msrs host; + } msr_autoload; + struct { + int loaded; +@@ -2377,9 +2525,20 @@ static void clear_atomic_switch_msr_special(struct vcpu_vmx *vmx, + vm_exit_controls_clearbit(vmx, exit); + } + ++static int find_msr(struct vmx_msrs *m, unsigned int msr) ++{ ++ unsigned int i; ++ ++ for (i = 0; i < m->nr; ++i) { ++ if (m->val[i].index == msr) ++ return i; ++ } ++ return -ENOENT; ++} ++ + static void clear_atomic_switch_msr(struct vcpu_vmx *vmx, unsigned msr) + { +- unsigned i; ++ int i; + struct msr_autoload *m = &vmx->msr_autoload; + + switch (msr) { +@@ -2400,18 +2559,21 @@ static void clear_atomic_switch_msr(struct vcpu_vmx *vmx, unsigned msr) + } + break; + } ++ i = find_msr(&m->guest, msr); ++ if (i < 0) ++ goto skip_guest; ++ --m->guest.nr; ++ m->guest.val[i] = m->guest.val[m->guest.nr]; ++ vmcs_write32(VM_ENTRY_MSR_LOAD_COUNT, m->guest.nr); + +- for (i = 0; i < m->nr; ++i) +- if (m->guest[i].index == msr) +- break; +- +- if (i == m->nr) ++skip_guest: ++ i = find_msr(&m->host, msr); ++ if (i < 0) + return; +- --m->nr; +- m->guest[i] = m->guest[m->nr]; +- m->host[i] = m->host[m->nr]; +- vmcs_write32(VM_ENTRY_MSR_LOAD_COUNT, m->nr); +- vmcs_write32(VM_EXIT_MSR_LOAD_COUNT, m->nr); ++ ++ --m->host.nr; ++ m->host.val[i] = m->host.val[m->host.nr]; ++ vmcs_write32(VM_EXIT_MSR_LOAD_COUNT, m->host.nr); + } + + static void add_atomic_switch_msr_special(struct vcpu_vmx *vmx, +@@ -2426,9 +2588,9 @@ static void add_atomic_switch_msr_special(struct vcpu_vmx *vmx, + } + + static void add_atomic_switch_msr(struct vcpu_vmx *vmx, unsigned msr, +- u64 guest_val, u64 host_val) ++ u64 guest_val, u64 host_val, bool entry_only) + { +- unsigned i; ++ int i, j = 0; + struct msr_autoload *m = &vmx->msr_autoload; + + switch (msr) { +@@ -2463,24 +2625,31 @@ static void add_atomic_switch_msr(struct vcpu_vmx *vmx, unsigned msr, + wrmsrl(MSR_IA32_PEBS_ENABLE, 0); + } + +- for (i = 0; i < m->nr; ++i) +- if (m->guest[i].index == msr) +- break; ++ i = find_msr(&m->guest, msr); ++ if (!entry_only) ++ j = find_msr(&m->host, msr); + +- if (i == NR_AUTOLOAD_MSRS) { ++ if (i == NR_AUTOLOAD_MSRS || j == NR_AUTOLOAD_MSRS) { + printk_once(KERN_WARNING "Not enough msr switch entries. " + "Can't add msr %x\n", msr); + return; +- } else if (i == m->nr) { +- ++m->nr; +- vmcs_write32(VM_ENTRY_MSR_LOAD_COUNT, m->nr); +- vmcs_write32(VM_EXIT_MSR_LOAD_COUNT, m->nr); + } ++ if (i < 0) { ++ i = m->guest.nr++; ++ vmcs_write32(VM_ENTRY_MSR_LOAD_COUNT, m->guest.nr); ++ } ++ m->guest.val[i].index = msr; ++ m->guest.val[i].value = guest_val; ++ ++ if (entry_only) ++ return; + +- m->guest[i].index = msr; +- m->guest[i].value = guest_val; +- m->host[i].index = msr; +- m->host[i].value = host_val; ++ if (j < 0) { ++ j = m->host.nr++; ++ vmcs_write32(VM_EXIT_MSR_LOAD_COUNT, m->host.nr); ++ } ++ m->host.val[j].index = msr; ++ m->host.val[j].value = host_val; + } + + static bool update_transition_efer(struct vcpu_vmx *vmx, int efer_offset) +@@ -2524,7 +2693,7 @@ static bool update_transition_efer(struct vcpu_vmx *vmx, int efer_offset) + guest_efer &= ~EFER_LME; + if (guest_efer != host_efer) + add_atomic_switch_msr(vmx, MSR_EFER, +- guest_efer, host_efer); ++ guest_efer, host_efer, false); + return false; + } else { + guest_efer &= ~ignore_bits; +@@ -3987,7 +4156,7 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) + vcpu->arch.ia32_xss = data; + if (vcpu->arch.ia32_xss != host_xss) + add_atomic_switch_msr(vmx, MSR_IA32_XSS, +- vcpu->arch.ia32_xss, host_xss); ++ vcpu->arch.ia32_xss, host_xss, false); + else + clear_atomic_switch_msr(vmx, MSR_IA32_XSS); + break; +@@ -6274,9 +6443,9 @@ static void vmx_vcpu_setup(struct vcpu_vmx *vmx) + + vmcs_write32(VM_EXIT_MSR_STORE_COUNT, 0); + vmcs_write32(VM_EXIT_MSR_LOAD_COUNT, 0); +- vmcs_write64(VM_EXIT_MSR_LOAD_ADDR, __pa(vmx->msr_autoload.host)); ++ vmcs_write64(VM_EXIT_MSR_LOAD_ADDR, __pa(vmx->msr_autoload.host.val)); + vmcs_write32(VM_ENTRY_MSR_LOAD_COUNT, 0); +- vmcs_write64(VM_ENTRY_MSR_LOAD_ADDR, __pa(vmx->msr_autoload.guest)); ++ vmcs_write64(VM_ENTRY_MSR_LOAD_ADDR, __pa(vmx->msr_autoload.guest.val)); + + if (vmcs_config.vmentry_ctrl & VM_ENTRY_LOAD_IA32_PAT) + vmcs_write64(GUEST_IA32_PAT, vmx->vcpu.arch.pat); +@@ -6296,8 +6465,7 @@ static void vmx_vcpu_setup(struct vcpu_vmx *vmx) + ++vmx->nmsrs; + } + +- if (boot_cpu_has(X86_FEATURE_ARCH_CAPABILITIES)) +- rdmsrl(MSR_IA32_ARCH_CAPABILITIES, vmx->arch_capabilities); ++ vmx->arch_capabilities = kvm_get_arch_capabilities(); + + vm_exit_controls_init(vmx, vmcs_config.vmexit_ctrl); + +@@ -9548,6 +9716,79 @@ static int vmx_handle_exit(struct kvm_vcpu *vcpu) + } + } + ++/* ++ * Software based L1D cache flush which is used when microcode providing ++ * the cache control MSR is not loaded. ++ * ++ * The L1D cache is 32 KiB on Nehalem and later microarchitectures, but to ++ * flush it is required to read in 64 KiB because the replacement algorithm ++ * is not exactly LRU. This could be sized at runtime via topology ++ * information but as all relevant affected CPUs have 32KiB L1D cache size ++ * there is no point in doing so. ++ */ ++#define L1D_CACHE_ORDER 4 ++static void *vmx_l1d_flush_pages; ++ ++static void vmx_l1d_flush(struct kvm_vcpu *vcpu) ++{ ++ int size = PAGE_SIZE << L1D_CACHE_ORDER; ++ ++ /* ++ * This code is only executed when the the flush mode is 'cond' or ++ * 'always' ++ */ ++ if (static_branch_likely(&vmx_l1d_flush_cond)) { ++ bool flush_l1d; ++ ++ /* ++ * Clear the per-vcpu flush bit, it gets set again ++ * either from vcpu_run() or from one of the unsafe ++ * VMEXIT handlers. ++ */ ++ flush_l1d = vcpu->arch.l1tf_flush_l1d; ++ vcpu->arch.l1tf_flush_l1d = false; ++ ++ /* ++ * Clear the per-cpu flush bit, it gets set again from ++ * the interrupt handlers. ++ */ ++ flush_l1d |= kvm_get_cpu_l1tf_flush_l1d(); ++ kvm_clear_cpu_l1tf_flush_l1d(); ++ ++ if (!flush_l1d) ++ return; ++ } ++ ++ vcpu->stat.l1d_flush++; ++ ++ if (static_cpu_has(X86_FEATURE_FLUSH_L1D)) { ++ wrmsrl(MSR_IA32_FLUSH_CMD, L1D_FLUSH); ++ return; ++ } ++ ++ asm volatile( ++ /* First ensure the pages are in the TLB */ ++ "xorl %%eax, %%eax\n" ++ ".Lpopulate_tlb:\n\t" ++ "movzbl (%[flush_pages], %%" _ASM_AX "), %%ecx\n\t" ++ "addl $4096, %%eax\n\t" ++ "cmpl %%eax, %[size]\n\t" ++ "jne .Lpopulate_tlb\n\t" ++ "xorl %%eax, %%eax\n\t" ++ "cpuid\n\t" ++ /* Now fill the cache */ ++ "xorl %%eax, %%eax\n" ++ ".Lfill_cache:\n" ++ "movzbl (%[flush_pages], %%" _ASM_AX "), %%ecx\n\t" ++ "addl $64, %%eax\n\t" ++ "cmpl %%eax, %[size]\n\t" ++ "jne .Lfill_cache\n\t" ++ "lfence\n" ++ :: [flush_pages] "r" (vmx_l1d_flush_pages), ++ [size] "r" (size) ++ : "eax", "ebx", "ecx", "edx"); ++} ++ + static void update_cr8_intercept(struct kvm_vcpu *vcpu, int tpr, int irr) + { + struct vmcs12 *vmcs12 = get_vmcs12(vcpu); +@@ -9949,7 +10190,7 @@ static void atomic_switch_perf_msrs(struct vcpu_vmx *vmx) + clear_atomic_switch_msr(vmx, msrs[i].msr); + else + add_atomic_switch_msr(vmx, msrs[i].msr, msrs[i].guest, +- msrs[i].host); ++ msrs[i].host, false); + } + + static void vmx_arm_hv_timer(struct kvm_vcpu *vcpu) +@@ -10044,6 +10285,9 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu) + evmcs_rsp = static_branch_unlikely(&enable_evmcs) ? + (unsigned long)¤t_evmcs->host_rsp : 0; + ++ if (static_branch_unlikely(&vmx_l1d_should_flush)) ++ vmx_l1d_flush(vcpu); ++ + asm( + /* Store host registers */ + "push %%" _ASM_DX "; push %%" _ASM_BP ";" +@@ -10403,10 +10647,37 @@ free_vcpu: + return ERR_PTR(err); + } + ++#define L1TF_MSG_SMT "L1TF CPU bug present and SMT on, data leak possible. See CVE-2018-3646 and https://www.kernel.org/doc/html/latest/admin-guide/l1tf.html for details.\n" ++#define L1TF_MSG_L1D "L1TF CPU bug present and virtualization mitigation disabled, data leak possible. See CVE-2018-3646 and https://www.kernel.org/doc/html/latest/admin-guide/l1tf.html for details.\n" ++ + static int vmx_vm_init(struct kvm *kvm) + { + if (!ple_gap) + kvm->arch.pause_in_guest = true; ++ ++ if (boot_cpu_has(X86_BUG_L1TF) && enable_ept) { ++ switch (l1tf_mitigation) { ++ case L1TF_MITIGATION_OFF: ++ case L1TF_MITIGATION_FLUSH_NOWARN: ++ /* 'I explicitly don't care' is set */ ++ break; ++ case L1TF_MITIGATION_FLUSH: ++ case L1TF_MITIGATION_FLUSH_NOSMT: ++ case L1TF_MITIGATION_FULL: ++ /* ++ * Warn upon starting the first VM in a potentially ++ * insecure environment. ++ */ ++ if (cpu_smt_control == CPU_SMT_ENABLED) ++ pr_warn_once(L1TF_MSG_SMT); ++ if (l1tf_vmx_mitigation == VMENTER_L1D_FLUSH_NEVER) ++ pr_warn_once(L1TF_MSG_L1D); ++ break; ++ case L1TF_MITIGATION_FULL_FORCE: ++ /* Flush is enforced */ ++ break; ++ } ++ } + return 0; + } + +@@ -11260,10 +11531,10 @@ static void prepare_vmcs02_full(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12) + * Set the MSR load/store lists to match L0's settings. + */ + vmcs_write32(VM_EXIT_MSR_STORE_COUNT, 0); +- vmcs_write32(VM_EXIT_MSR_LOAD_COUNT, vmx->msr_autoload.nr); +- vmcs_write64(VM_EXIT_MSR_LOAD_ADDR, __pa(vmx->msr_autoload.host)); +- vmcs_write32(VM_ENTRY_MSR_LOAD_COUNT, vmx->msr_autoload.nr); +- vmcs_write64(VM_ENTRY_MSR_LOAD_ADDR, __pa(vmx->msr_autoload.guest)); ++ vmcs_write32(VM_EXIT_MSR_LOAD_COUNT, vmx->msr_autoload.host.nr); ++ vmcs_write64(VM_EXIT_MSR_LOAD_ADDR, __pa(vmx->msr_autoload.host.val)); ++ vmcs_write32(VM_ENTRY_MSR_LOAD_COUNT, vmx->msr_autoload.guest.nr); ++ vmcs_write64(VM_ENTRY_MSR_LOAD_ADDR, __pa(vmx->msr_autoload.guest.val)); + + set_cr4_guest_host_mask(vmx); + +@@ -11899,6 +12170,9 @@ static int nested_vmx_run(struct kvm_vcpu *vcpu, bool launch) + return ret; + } + ++ /* Hide L1D cache contents from the nested guest. */ ++ vmx->vcpu.arch.l1tf_flush_l1d = true; ++ + /* + * If we're entering a halted L2 vcpu and the L2 vcpu won't be woken + * by event injection, halt vcpu. +@@ -12419,8 +12693,8 @@ static void nested_vmx_vmexit(struct kvm_vcpu *vcpu, u32 exit_reason, + vmx_segment_cache_clear(vmx); + + /* Update any VMCS fields that might have changed while L2 ran */ +- vmcs_write32(VM_EXIT_MSR_LOAD_COUNT, vmx->msr_autoload.nr); +- vmcs_write32(VM_ENTRY_MSR_LOAD_COUNT, vmx->msr_autoload.nr); ++ vmcs_write32(VM_EXIT_MSR_LOAD_COUNT, vmx->msr_autoload.host.nr); ++ vmcs_write32(VM_ENTRY_MSR_LOAD_COUNT, vmx->msr_autoload.guest.nr); + vmcs_write64(TSC_OFFSET, vcpu->arch.tsc_offset); + if (vmx->hv_deadline_tsc == -1) + vmcs_clear_bits(PIN_BASED_VM_EXEC_CONTROL, +@@ -13137,6 +13411,51 @@ static struct kvm_x86_ops vmx_x86_ops __ro_after_init = { + .enable_smi_window = enable_smi_window, + }; + ++static void vmx_cleanup_l1d_flush(void) ++{ ++ if (vmx_l1d_flush_pages) { ++ free_pages((unsigned long)vmx_l1d_flush_pages, L1D_CACHE_ORDER); ++ vmx_l1d_flush_pages = NULL; ++ } ++ /* Restore state so sysfs ignores VMX */ ++ l1tf_vmx_mitigation = VMENTER_L1D_FLUSH_AUTO; ++} ++ ++static void vmx_exit(void) ++{ ++#ifdef CONFIG_KEXEC_CORE ++ RCU_INIT_POINTER(crash_vmclear_loaded_vmcss, NULL); ++ synchronize_rcu(); ++#endif ++ ++ kvm_exit(); ++ ++#if IS_ENABLED(CONFIG_HYPERV) ++ if (static_branch_unlikely(&enable_evmcs)) { ++ int cpu; ++ struct hv_vp_assist_page *vp_ap; ++ /* ++ * Reset everything to support using non-enlightened VMCS ++ * access later (e.g. when we reload the module with ++ * enlightened_vmcs=0) ++ */ ++ for_each_online_cpu(cpu) { ++ vp_ap = hv_get_vp_assist_page(cpu); ++ ++ if (!vp_ap) ++ continue; ++ ++ vp_ap->current_nested_vmcs = 0; ++ vp_ap->enlighten_vmentry = 0; ++ } ++ ++ static_branch_disable(&enable_evmcs); ++ } ++#endif ++ vmx_cleanup_l1d_flush(); ++} ++module_exit(vmx_exit); ++ + static int __init vmx_init(void) + { + int r; +@@ -13171,10 +13490,25 @@ static int __init vmx_init(void) + #endif + + r = kvm_init(&vmx_x86_ops, sizeof(struct vcpu_vmx), +- __alignof__(struct vcpu_vmx), THIS_MODULE); ++ __alignof__(struct vcpu_vmx), THIS_MODULE); + if (r) + return r; + ++ /* ++ * Must be called after kvm_init() so enable_ept is properly set ++ * up. Hand the parameter mitigation value in which was stored in ++ * the pre module init parser. If no parameter was given, it will ++ * contain 'auto' which will be turned into the default 'cond' ++ * mitigation mode. ++ */ ++ if (boot_cpu_has(X86_BUG_L1TF)) { ++ r = vmx_setup_l1d_flush(vmentry_l1d_flush_param); ++ if (r) { ++ vmx_exit(); ++ return r; ++ } ++ } ++ + #ifdef CONFIG_KEXEC_CORE + rcu_assign_pointer(crash_vmclear_loaded_vmcss, + crash_vmclear_local_loaded_vmcss); +@@ -13183,39 +13517,4 @@ static int __init vmx_init(void) + + return 0; + } +- +-static void __exit vmx_exit(void) +-{ +-#ifdef CONFIG_KEXEC_CORE +- RCU_INIT_POINTER(crash_vmclear_loaded_vmcss, NULL); +- synchronize_rcu(); +-#endif +- +- kvm_exit(); +- +-#if IS_ENABLED(CONFIG_HYPERV) +- if (static_branch_unlikely(&enable_evmcs)) { +- int cpu; +- struct hv_vp_assist_page *vp_ap; +- /* +- * Reset everything to support using non-enlightened VMCS +- * access later (e.g. when we reload the module with +- * enlightened_vmcs=0) +- */ +- for_each_online_cpu(cpu) { +- vp_ap = hv_get_vp_assist_page(cpu); +- +- if (!vp_ap) +- continue; +- +- vp_ap->current_nested_vmcs = 0; +- vp_ap->enlighten_vmentry = 0; +- } +- +- static_branch_disable(&enable_evmcs); +- } +-#endif +-} +- +-module_init(vmx_init) +-module_exit(vmx_exit) ++module_init(vmx_init); +diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c +index 2b812b3c5088..a5caa5e5480c 100644 +--- a/arch/x86/kvm/x86.c ++++ b/arch/x86/kvm/x86.c +@@ -195,6 +195,7 @@ struct kvm_stats_debugfs_item debugfs_entries[] = { + { "irq_injections", VCPU_STAT(irq_injections) }, + { "nmi_injections", VCPU_STAT(nmi_injections) }, + { "req_event", VCPU_STAT(req_event) }, ++ { "l1d_flush", VCPU_STAT(l1d_flush) }, + { "mmu_shadow_zapped", VM_STAT(mmu_shadow_zapped) }, + { "mmu_pte_write", VM_STAT(mmu_pte_write) }, + { "mmu_pte_updated", VM_STAT(mmu_pte_updated) }, +@@ -1102,11 +1103,35 @@ static u32 msr_based_features[] = { + + static unsigned int num_msr_based_features; + ++u64 kvm_get_arch_capabilities(void) ++{ ++ u64 data; ++ ++ rdmsrl_safe(MSR_IA32_ARCH_CAPABILITIES, &data); ++ ++ /* ++ * If we're doing cache flushes (either "always" or "cond") ++ * we will do one whenever the guest does a vmlaunch/vmresume. ++ * If an outer hypervisor is doing the cache flush for us ++ * (VMENTER_L1D_FLUSH_NESTED_VM), we can safely pass that ++ * capability to the guest too, and if EPT is disabled we're not ++ * vulnerable. Overall, only VMENTER_L1D_FLUSH_NEVER will ++ * require a nested hypervisor to do a flush of its own. ++ */ ++ if (l1tf_vmx_mitigation != VMENTER_L1D_FLUSH_NEVER) ++ data |= ARCH_CAP_SKIP_VMENTRY_L1DFLUSH; ++ ++ return data; ++} ++EXPORT_SYMBOL_GPL(kvm_get_arch_capabilities); ++ + static int kvm_get_msr_feature(struct kvm_msr_entry *msr) + { + switch (msr->index) { +- case MSR_IA32_UCODE_REV: + case MSR_IA32_ARCH_CAPABILITIES: ++ msr->data = kvm_get_arch_capabilities(); ++ break; ++ case MSR_IA32_UCODE_REV: + rdmsrl_safe(msr->index, &msr->data); + break; + default: +@@ -4876,6 +4901,9 @@ static int emulator_write_std(struct x86_emulate_ctxt *ctxt, gva_t addr, void *v + int kvm_write_guest_virt_system(struct kvm_vcpu *vcpu, gva_t addr, void *val, + unsigned int bytes, struct x86_exception *exception) + { ++ /* kvm_write_guest_virt_system can pull in tons of pages. */ ++ vcpu->arch.l1tf_flush_l1d = true; ++ + return kvm_write_guest_virt_helper(addr, val, bytes, vcpu, + PFERR_WRITE_MASK, exception); + } +@@ -6052,6 +6080,8 @@ int x86_emulate_instruction(struct kvm_vcpu *vcpu, + bool writeback = true; + bool write_fault_to_spt = vcpu->arch.write_fault_to_shadow_pgtable; + ++ vcpu->arch.l1tf_flush_l1d = true; ++ + /* + * Clear write_fault_to_shadow_pgtable here to ensure it is + * never reused. +@@ -7581,6 +7611,7 @@ static int vcpu_run(struct kvm_vcpu *vcpu) + struct kvm *kvm = vcpu->kvm; + + vcpu->srcu_idx = srcu_read_lock(&kvm->srcu); ++ vcpu->arch.l1tf_flush_l1d = true; + + for (;;) { + if (kvm_vcpu_running(vcpu)) { +@@ -8700,6 +8731,7 @@ void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu) + + void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu) + { ++ vcpu->arch.l1tf_flush_l1d = true; + kvm_x86_ops->sched_in(vcpu, cpu); + } + +diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c +index cee58a972cb2..83241eb71cd4 100644 +--- a/arch/x86/mm/init.c ++++ b/arch/x86/mm/init.c +@@ -4,6 +4,8 @@ + #include + #include + #include /* for max_low_pfn */ ++#include ++#include + + #include + #include +@@ -880,3 +882,26 @@ void update_cache_mode_entry(unsigned entry, enum page_cache_mode cache) + __cachemode2pte_tbl[cache] = __cm_idx2pte(entry); + __pte2cachemode_tbl[entry] = cache; + } ++ ++#ifdef CONFIG_SWAP ++unsigned long max_swapfile_size(void) ++{ ++ unsigned long pages; ++ ++ pages = generic_max_swapfile_size(); ++ ++ if (boot_cpu_has_bug(X86_BUG_L1TF)) { ++ /* Limit the swap file size to MAX_PA/2 for L1TF workaround */ ++ unsigned long l1tf_limit = l1tf_pfn_limit() + 1; ++ /* ++ * We encode swap offsets also with 3 bits below those for pfn ++ * which makes the usable limit higher. ++ */ ++#if CONFIG_PGTABLE_LEVELS > 2 ++ l1tf_limit <<= PAGE_SHIFT - SWP_OFFSET_FIRST_BIT; ++#endif ++ pages = min_t(unsigned long, l1tf_limit, pages); ++ } ++ return pages; ++} ++#endif +diff --git a/arch/x86/mm/kmmio.c b/arch/x86/mm/kmmio.c +index 7c8686709636..79eb55ce69a9 100644 +--- a/arch/x86/mm/kmmio.c ++++ b/arch/x86/mm/kmmio.c +@@ -126,24 +126,29 @@ static struct kmmio_fault_page *get_kmmio_fault_page(unsigned long addr) + + static void clear_pmd_presence(pmd_t *pmd, bool clear, pmdval_t *old) + { ++ pmd_t new_pmd; + pmdval_t v = pmd_val(*pmd); + if (clear) { +- *old = v & _PAGE_PRESENT; +- v &= ~_PAGE_PRESENT; +- } else /* presume this has been called with clear==true previously */ +- v |= *old; +- set_pmd(pmd, __pmd(v)); ++ *old = v; ++ new_pmd = pmd_mknotpresent(*pmd); ++ } else { ++ /* Presume this has been called with clear==true previously */ ++ new_pmd = __pmd(*old); ++ } ++ set_pmd(pmd, new_pmd); + } + + static void clear_pte_presence(pte_t *pte, bool clear, pteval_t *old) + { + pteval_t v = pte_val(*pte); + if (clear) { +- *old = v & _PAGE_PRESENT; +- v &= ~_PAGE_PRESENT; +- } else /* presume this has been called with clear==true previously */ +- v |= *old; +- set_pte_atomic(pte, __pte(v)); ++ *old = v; ++ /* Nothing should care about address */ ++ pte_clear(&init_mm, 0, pte); ++ } else { ++ /* Presume this has been called with clear==true previously */ ++ set_pte_atomic(pte, __pte(*old)); ++ } + } + + static int clear_page_presence(struct kmmio_fault_page *f, bool clear) +diff --git a/arch/x86/mm/mmap.c b/arch/x86/mm/mmap.c +index 48c591251600..f40ab8185d94 100644 +--- a/arch/x86/mm/mmap.c ++++ b/arch/x86/mm/mmap.c +@@ -240,3 +240,24 @@ int valid_mmap_phys_addr_range(unsigned long pfn, size_t count) + + return phys_addr_valid(addr + count - 1); + } ++ ++/* ++ * Only allow root to set high MMIO mappings to PROT_NONE. ++ * This prevents an unpriv. user to set them to PROT_NONE and invert ++ * them, then pointing to valid memory for L1TF speculation. ++ * ++ * Note: for locked down kernels may want to disable the root override. ++ */ ++bool pfn_modify_allowed(unsigned long pfn, pgprot_t prot) ++{ ++ if (!boot_cpu_has_bug(X86_BUG_L1TF)) ++ return true; ++ if (!__pte_needs_invert(pgprot_val(prot))) ++ return true; ++ /* If it's real memory always allow */ ++ if (pfn_valid(pfn)) ++ return true; ++ if (pfn > l1tf_pfn_limit() && !capable(CAP_SYS_ADMIN)) ++ return false; ++ return true; ++} +diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c +index 3bded76e8d5c..7bb6f65c79de 100644 +--- a/arch/x86/mm/pageattr.c ++++ b/arch/x86/mm/pageattr.c +@@ -1014,8 +1014,8 @@ static long populate_pmd(struct cpa_data *cpa, + + pmd = pmd_offset(pud, start); + +- set_pmd(pmd, __pmd(cpa->pfn << PAGE_SHIFT | _PAGE_PSE | +- massage_pgprot(pmd_pgprot))); ++ set_pmd(pmd, pmd_mkhuge(pfn_pmd(cpa->pfn, ++ canon_pgprot(pmd_pgprot)))); + + start += PMD_SIZE; + cpa->pfn += PMD_SIZE >> PAGE_SHIFT; +@@ -1087,8 +1087,8 @@ static int populate_pud(struct cpa_data *cpa, unsigned long start, p4d_t *p4d, + * Map everything starting from the Gb boundary, possibly with 1G pages + */ + while (boot_cpu_has(X86_FEATURE_GBPAGES) && end - start >= PUD_SIZE) { +- set_pud(pud, __pud(cpa->pfn << PAGE_SHIFT | _PAGE_PSE | +- massage_pgprot(pud_pgprot))); ++ set_pud(pud, pud_mkhuge(pfn_pud(cpa->pfn, ++ canon_pgprot(pud_pgprot)))); + + start += PUD_SIZE; + cpa->pfn += PUD_SIZE >> PAGE_SHIFT; +diff --git a/arch/x86/mm/pti.c b/arch/x86/mm/pti.c +index 4d418e705878..fb752d9a3ce9 100644 +--- a/arch/x86/mm/pti.c ++++ b/arch/x86/mm/pti.c +@@ -45,6 +45,7 @@ + #include + #include + #include ++#include + + #undef pr_fmt + #define pr_fmt(fmt) "Kernel/User page tables isolation: " fmt +diff --git a/arch/x86/platform/intel-mid/device_libs/platform_mrfld_wdt.c b/arch/x86/platform/intel-mid/device_libs/platform_mrfld_wdt.c +index 4f5fa65a1011..2acd6be13375 100644 +--- a/arch/x86/platform/intel-mid/device_libs/platform_mrfld_wdt.c ++++ b/arch/x86/platform/intel-mid/device_libs/platform_mrfld_wdt.c +@@ -18,6 +18,7 @@ + #include + #include + #include ++#include + + #define TANGIER_EXT_TIMER0_MSI 12 + +diff --git a/arch/x86/platform/uv/tlb_uv.c b/arch/x86/platform/uv/tlb_uv.c +index ca446da48fd2..3866b96a7ee7 100644 +--- a/arch/x86/platform/uv/tlb_uv.c ++++ b/arch/x86/platform/uv/tlb_uv.c +@@ -1285,6 +1285,7 @@ void uv_bau_message_interrupt(struct pt_regs *regs) + struct msg_desc msgdesc; + + ack_APIC_irq(); ++ kvm_set_cpu_l1tf_flush_l1d(); + time_start = get_cycles(); + + bcp = &per_cpu(bau_control, smp_processor_id()); +diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c +index 3b5318505c69..2eeddd814653 100644 +--- a/arch/x86/xen/enlighten.c ++++ b/arch/x86/xen/enlighten.c +@@ -3,6 +3,7 @@ + #endif + #include + #include ++#include + + #include + #include +diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c +index 30cc9c877ebb..eb9443d5bae1 100644 +--- a/drivers/base/cpu.c ++++ b/drivers/base/cpu.c +@@ -540,16 +540,24 @@ ssize_t __weak cpu_show_spec_store_bypass(struct device *dev, + return sprintf(buf, "Not affected\n"); + } + ++ssize_t __weak cpu_show_l1tf(struct device *dev, ++ struct device_attribute *attr, char *buf) ++{ ++ return sprintf(buf, "Not affected\n"); ++} ++ + static DEVICE_ATTR(meltdown, 0444, cpu_show_meltdown, NULL); + static DEVICE_ATTR(spectre_v1, 0444, cpu_show_spectre_v1, NULL); + static DEVICE_ATTR(spectre_v2, 0444, cpu_show_spectre_v2, NULL); + static DEVICE_ATTR(spec_store_bypass, 0444, cpu_show_spec_store_bypass, NULL); ++static DEVICE_ATTR(l1tf, 0444, cpu_show_l1tf, NULL); + + static struct attribute *cpu_root_vulnerabilities_attrs[] = { + &dev_attr_meltdown.attr, + &dev_attr_spectre_v1.attr, + &dev_attr_spectre_v2.attr, + &dev_attr_spec_store_bypass.attr, ++ &dev_attr_l1tf.attr, + NULL + }; + +diff --git a/drivers/gpu/drm/i915/i915_pmu.c b/drivers/gpu/drm/i915/i915_pmu.c +index dc87797db500..b50b74053664 100644 +--- a/drivers/gpu/drm/i915/i915_pmu.c ++++ b/drivers/gpu/drm/i915/i915_pmu.c +@@ -4,6 +4,7 @@ + * Copyright © 2017-2018 Intel Corporation + */ + ++#include + #include "i915_pmu.h" + #include "intel_ringbuffer.h" + #include "i915_drv.h" +diff --git a/drivers/gpu/drm/i915/intel_lpe_audio.c b/drivers/gpu/drm/i915/intel_lpe_audio.c +index 6269750e2b54..b4941101f21a 100644 +--- a/drivers/gpu/drm/i915/intel_lpe_audio.c ++++ b/drivers/gpu/drm/i915/intel_lpe_audio.c +@@ -62,6 +62,7 @@ + + #include + #include ++#include + #include + #include + +diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c +index f6325f1a89e8..d4d4a55f09f8 100644 +--- a/drivers/pci/controller/pci-hyperv.c ++++ b/drivers/pci/controller/pci-hyperv.c +@@ -45,6 +45,7 @@ + #include + #include + #include ++#include + #include + #include + #include +diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h +index f59639afaa39..26ca0276b503 100644 +--- a/include/asm-generic/pgtable.h ++++ b/include/asm-generic/pgtable.h +@@ -1083,6 +1083,18 @@ int phys_mem_access_prot_allowed(struct file *file, unsigned long pfn, + static inline void init_espfix_bsp(void) { } + #endif + ++#ifndef __HAVE_ARCH_PFN_MODIFY_ALLOWED ++static inline bool pfn_modify_allowed(unsigned long pfn, pgprot_t prot) ++{ ++ return true; ++} ++ ++static inline bool arch_has_pfn_modify_check(void) ++{ ++ return false; ++} ++#endif /* !_HAVE_ARCH_PFN_MODIFY_ALLOWED */ ++ + #endif /* !__ASSEMBLY__ */ + + #ifndef io_remap_pfn_range +diff --git a/include/linux/cpu.h b/include/linux/cpu.h +index 3233fbe23594..45789a892c41 100644 +--- a/include/linux/cpu.h ++++ b/include/linux/cpu.h +@@ -55,6 +55,8 @@ extern ssize_t cpu_show_spectre_v2(struct device *dev, + struct device_attribute *attr, char *buf); + extern ssize_t cpu_show_spec_store_bypass(struct device *dev, + struct device_attribute *attr, char *buf); ++extern ssize_t cpu_show_l1tf(struct device *dev, ++ struct device_attribute *attr, char *buf); + + extern __printf(4, 5) + struct device *cpu_device_create(struct device *parent, void *drvdata, +@@ -166,4 +168,23 @@ void cpuhp_report_idle_dead(void); + static inline void cpuhp_report_idle_dead(void) { } + #endif /* #ifdef CONFIG_HOTPLUG_CPU */ + ++enum cpuhp_smt_control { ++ CPU_SMT_ENABLED, ++ CPU_SMT_DISABLED, ++ CPU_SMT_FORCE_DISABLED, ++ CPU_SMT_NOT_SUPPORTED, ++}; ++ ++#if defined(CONFIG_SMP) && defined(CONFIG_HOTPLUG_SMT) ++extern enum cpuhp_smt_control cpu_smt_control; ++extern void cpu_smt_disable(bool force); ++extern void cpu_smt_check_topology_early(void); ++extern void cpu_smt_check_topology(void); ++#else ++# define cpu_smt_control (CPU_SMT_ENABLED) ++static inline void cpu_smt_disable(bool force) { } ++static inline void cpu_smt_check_topology_early(void) { } ++static inline void cpu_smt_check_topology(void) { } ++#endif ++ + #endif /* _LINUX_CPU_H_ */ +diff --git a/include/linux/swapfile.h b/include/linux/swapfile.h +index 06bd7b096167..e06febf62978 100644 +--- a/include/linux/swapfile.h ++++ b/include/linux/swapfile.h +@@ -10,5 +10,7 @@ extern spinlock_t swap_lock; + extern struct plist_head swap_active_head; + extern struct swap_info_struct *swap_info[]; + extern int try_to_unuse(unsigned int, bool, unsigned long); ++extern unsigned long generic_max_swapfile_size(void); ++extern unsigned long max_swapfile_size(void); + + #endif /* _LINUX_SWAPFILE_H */ +diff --git a/kernel/cpu.c b/kernel/cpu.c +index 2f8f338e77cf..f80afc674f02 100644 +--- a/kernel/cpu.c ++++ b/kernel/cpu.c +@@ -60,6 +60,7 @@ struct cpuhp_cpu_state { + bool rollback; + bool single; + bool bringup; ++ bool booted_once; + struct hlist_node *node; + struct hlist_node *last; + enum cpuhp_state cb_state; +@@ -342,6 +343,85 @@ void cpu_hotplug_enable(void) + EXPORT_SYMBOL_GPL(cpu_hotplug_enable); + #endif /* CONFIG_HOTPLUG_CPU */ + ++#ifdef CONFIG_HOTPLUG_SMT ++enum cpuhp_smt_control cpu_smt_control __read_mostly = CPU_SMT_ENABLED; ++EXPORT_SYMBOL_GPL(cpu_smt_control); ++ ++static bool cpu_smt_available __read_mostly; ++ ++void __init cpu_smt_disable(bool force) ++{ ++ if (cpu_smt_control == CPU_SMT_FORCE_DISABLED || ++ cpu_smt_control == CPU_SMT_NOT_SUPPORTED) ++ return; ++ ++ if (force) { ++ pr_info("SMT: Force disabled\n"); ++ cpu_smt_control = CPU_SMT_FORCE_DISABLED; ++ } else { ++ cpu_smt_control = CPU_SMT_DISABLED; ++ } ++} ++ ++/* ++ * The decision whether SMT is supported can only be done after the full ++ * CPU identification. Called from architecture code before non boot CPUs ++ * are brought up. ++ */ ++void __init cpu_smt_check_topology_early(void) ++{ ++ if (!topology_smt_supported()) ++ cpu_smt_control = CPU_SMT_NOT_SUPPORTED; ++} ++ ++/* ++ * If SMT was disabled by BIOS, detect it here, after the CPUs have been ++ * brought online. This ensures the smt/l1tf sysfs entries are consistent ++ * with reality. cpu_smt_available is set to true during the bringup of non ++ * boot CPUs when a SMT sibling is detected. Note, this may overwrite ++ * cpu_smt_control's previous setting. ++ */ ++void __init cpu_smt_check_topology(void) ++{ ++ if (!cpu_smt_available) ++ cpu_smt_control = CPU_SMT_NOT_SUPPORTED; ++} ++ ++static int __init smt_cmdline_disable(char *str) ++{ ++ cpu_smt_disable(str && !strcmp(str, "force")); ++ return 0; ++} ++early_param("nosmt", smt_cmdline_disable); ++ ++static inline bool cpu_smt_allowed(unsigned int cpu) ++{ ++ if (topology_is_primary_thread(cpu)) ++ return true; ++ ++ /* ++ * If the CPU is not a 'primary' thread and the booted_once bit is ++ * set then the processor has SMT support. Store this information ++ * for the late check of SMT support in cpu_smt_check_topology(). ++ */ ++ if (per_cpu(cpuhp_state, cpu).booted_once) ++ cpu_smt_available = true; ++ ++ if (cpu_smt_control == CPU_SMT_ENABLED) ++ return true; ++ ++ /* ++ * On x86 it's required to boot all logical CPUs at least once so ++ * that the init code can get a chance to set CR4.MCE on each ++ * CPU. Otherwise, a broadacasted MCE observing CR4.MCE=0b on any ++ * core will shutdown the machine. ++ */ ++ return !per_cpu(cpuhp_state, cpu).booted_once; ++} ++#else ++static inline bool cpu_smt_allowed(unsigned int cpu) { return true; } ++#endif ++ + static inline enum cpuhp_state + cpuhp_set_state(struct cpuhp_cpu_state *st, enum cpuhp_state target) + { +@@ -422,6 +502,16 @@ static int bringup_wait_for_ap(unsigned int cpu) + stop_machine_unpark(cpu); + kthread_unpark(st->thread); + ++ /* ++ * SMT soft disabling on X86 requires to bring the CPU out of the ++ * BIOS 'wait for SIPI' state in order to set the CR4.MCE bit. The ++ * CPU marked itself as booted_once in cpu_notify_starting() so the ++ * cpu_smt_allowed() check will now return false if this is not the ++ * primary sibling. ++ */ ++ if (!cpu_smt_allowed(cpu)) ++ return -ECANCELED; ++ + if (st->target <= CPUHP_AP_ONLINE_IDLE) + return 0; + +@@ -754,7 +844,6 @@ static int takedown_cpu(unsigned int cpu) + + /* Park the smpboot threads */ + kthread_park(per_cpu_ptr(&cpuhp_state, cpu)->thread); +- smpboot_park_threads(cpu); + + /* + * Prevent irq alloc/free while the dying cpu reorganizes the +@@ -907,20 +996,19 @@ out: + return ret; + } + ++static int cpu_down_maps_locked(unsigned int cpu, enum cpuhp_state target) ++{ ++ if (cpu_hotplug_disabled) ++ return -EBUSY; ++ return _cpu_down(cpu, 0, target); ++} ++ + static int do_cpu_down(unsigned int cpu, enum cpuhp_state target) + { + int err; + + cpu_maps_update_begin(); +- +- if (cpu_hotplug_disabled) { +- err = -EBUSY; +- goto out; +- } +- +- err = _cpu_down(cpu, 0, target); +- +-out: ++ err = cpu_down_maps_locked(cpu, target); + cpu_maps_update_done(); + return err; + } +@@ -949,6 +1037,7 @@ void notify_cpu_starting(unsigned int cpu) + int ret; + + rcu_cpu_starting(cpu); /* Enables RCU usage on this CPU. */ ++ st->booted_once = true; + while (st->state < target) { + st->state++; + ret = cpuhp_invoke_callback(cpu, st->state, true, NULL, NULL); +@@ -1058,6 +1147,10 @@ static int do_cpu_up(unsigned int cpu, enum cpuhp_state target) + err = -EBUSY; + goto out; + } ++ if (!cpu_smt_allowed(cpu)) { ++ err = -EPERM; ++ goto out; ++ } + + err = _cpu_up(cpu, 0, target); + out: +@@ -1332,7 +1425,7 @@ static struct cpuhp_step cpuhp_hp_states[] = { + [CPUHP_AP_SMPBOOT_THREADS] = { + .name = "smpboot/threads:online", + .startup.single = smpboot_unpark_threads, +- .teardown.single = NULL, ++ .teardown.single = smpboot_park_threads, + }, + [CPUHP_AP_IRQ_AFFINITY_ONLINE] = { + .name = "irq/affinity:online", +@@ -1906,10 +1999,172 @@ static const struct attribute_group cpuhp_cpu_root_attr_group = { + NULL + }; + ++#ifdef CONFIG_HOTPLUG_SMT ++ ++static const char *smt_states[] = { ++ [CPU_SMT_ENABLED] = "on", ++ [CPU_SMT_DISABLED] = "off", ++ [CPU_SMT_FORCE_DISABLED] = "forceoff", ++ [CPU_SMT_NOT_SUPPORTED] = "notsupported", ++}; ++ ++static ssize_t ++show_smt_control(struct device *dev, struct device_attribute *attr, char *buf) ++{ ++ return snprintf(buf, PAGE_SIZE - 2, "%s\n", smt_states[cpu_smt_control]); ++} ++ ++static void cpuhp_offline_cpu_device(unsigned int cpu) ++{ ++ struct device *dev = get_cpu_device(cpu); ++ ++ dev->offline = true; ++ /* Tell user space about the state change */ ++ kobject_uevent(&dev->kobj, KOBJ_OFFLINE); ++} ++ ++static void cpuhp_online_cpu_device(unsigned int cpu) ++{ ++ struct device *dev = get_cpu_device(cpu); ++ ++ dev->offline = false; ++ /* Tell user space about the state change */ ++ kobject_uevent(&dev->kobj, KOBJ_ONLINE); ++} ++ ++static int cpuhp_smt_disable(enum cpuhp_smt_control ctrlval) ++{ ++ int cpu, ret = 0; ++ ++ cpu_maps_update_begin(); ++ for_each_online_cpu(cpu) { ++ if (topology_is_primary_thread(cpu)) ++ continue; ++ ret = cpu_down_maps_locked(cpu, CPUHP_OFFLINE); ++ if (ret) ++ break; ++ /* ++ * As this needs to hold the cpu maps lock it's impossible ++ * to call device_offline() because that ends up calling ++ * cpu_down() which takes cpu maps lock. cpu maps lock ++ * needs to be held as this might race against in kernel ++ * abusers of the hotplug machinery (thermal management). ++ * ++ * So nothing would update device:offline state. That would ++ * leave the sysfs entry stale and prevent onlining after ++ * smt control has been changed to 'off' again. This is ++ * called under the sysfs hotplug lock, so it is properly ++ * serialized against the regular offline usage. ++ */ ++ cpuhp_offline_cpu_device(cpu); ++ } ++ if (!ret) ++ cpu_smt_control = ctrlval; ++ cpu_maps_update_done(); ++ return ret; ++} ++ ++static int cpuhp_smt_enable(void) ++{ ++ int cpu, ret = 0; ++ ++ cpu_maps_update_begin(); ++ cpu_smt_control = CPU_SMT_ENABLED; ++ for_each_present_cpu(cpu) { ++ /* Skip online CPUs and CPUs on offline nodes */ ++ if (cpu_online(cpu) || !node_online(cpu_to_node(cpu))) ++ continue; ++ ret = _cpu_up(cpu, 0, CPUHP_ONLINE); ++ if (ret) ++ break; ++ /* See comment in cpuhp_smt_disable() */ ++ cpuhp_online_cpu_device(cpu); ++ } ++ cpu_maps_update_done(); ++ return ret; ++} ++ ++static ssize_t ++store_smt_control(struct device *dev, struct device_attribute *attr, ++ const char *buf, size_t count) ++{ ++ int ctrlval, ret; ++ ++ if (sysfs_streq(buf, "on")) ++ ctrlval = CPU_SMT_ENABLED; ++ else if (sysfs_streq(buf, "off")) ++ ctrlval = CPU_SMT_DISABLED; ++ else if (sysfs_streq(buf, "forceoff")) ++ ctrlval = CPU_SMT_FORCE_DISABLED; ++ else ++ return -EINVAL; ++ ++ if (cpu_smt_control == CPU_SMT_FORCE_DISABLED) ++ return -EPERM; ++ ++ if (cpu_smt_control == CPU_SMT_NOT_SUPPORTED) ++ return -ENODEV; ++ ++ ret = lock_device_hotplug_sysfs(); ++ if (ret) ++ return ret; ++ ++ if (ctrlval != cpu_smt_control) { ++ switch (ctrlval) { ++ case CPU_SMT_ENABLED: ++ ret = cpuhp_smt_enable(); ++ break; ++ case CPU_SMT_DISABLED: ++ case CPU_SMT_FORCE_DISABLED: ++ ret = cpuhp_smt_disable(ctrlval); ++ break; ++ } ++ } ++ ++ unlock_device_hotplug(); ++ return ret ? ret : count; ++} ++static DEVICE_ATTR(control, 0644, show_smt_control, store_smt_control); ++ ++static ssize_t ++show_smt_active(struct device *dev, struct device_attribute *attr, char *buf) ++{ ++ bool active = topology_max_smt_threads() > 1; ++ ++ return snprintf(buf, PAGE_SIZE - 2, "%d\n", active); ++} ++static DEVICE_ATTR(active, 0444, show_smt_active, NULL); ++ ++static struct attribute *cpuhp_smt_attrs[] = { ++ &dev_attr_control.attr, ++ &dev_attr_active.attr, ++ NULL ++}; ++ ++static const struct attribute_group cpuhp_smt_attr_group = { ++ .attrs = cpuhp_smt_attrs, ++ .name = "smt", ++ NULL ++}; ++ ++static int __init cpu_smt_state_init(void) ++{ ++ return sysfs_create_group(&cpu_subsys.dev_root->kobj, ++ &cpuhp_smt_attr_group); ++} ++ ++#else ++static inline int cpu_smt_state_init(void) { return 0; } ++#endif ++ + static int __init cpuhp_sysfs_init(void) + { + int cpu, ret; + ++ ret = cpu_smt_state_init(); ++ if (ret) ++ return ret; ++ + ret = sysfs_create_group(&cpu_subsys.dev_root->kobj, + &cpuhp_cpu_root_attr_group); + if (ret) +@@ -2012,5 +2267,8 @@ void __init boot_cpu_init(void) + */ + void __init boot_cpu_hotplug_init(void) + { +- per_cpu_ptr(&cpuhp_state, smp_processor_id())->state = CPUHP_ONLINE; ++#ifdef CONFIG_SMP ++ this_cpu_write(cpuhp_state.booted_once, true); ++#endif ++ this_cpu_write(cpuhp_state.state, CPUHP_ONLINE); + } +diff --git a/kernel/sched/core.c b/kernel/sched/core.c +index fe365c9a08e9..5ba96d9ddbde 100644 +--- a/kernel/sched/core.c ++++ b/kernel/sched/core.c +@@ -5774,6 +5774,18 @@ int sched_cpu_activate(unsigned int cpu) + struct rq *rq = cpu_rq(cpu); + struct rq_flags rf; + ++#ifdef CONFIG_SCHED_SMT ++ /* ++ * The sched_smt_present static key needs to be evaluated on every ++ * hotplug event because at boot time SMT might be disabled when ++ * the number of booted CPUs is limited. ++ * ++ * If then later a sibling gets hotplugged, then the key would stay ++ * off and SMT scheduling would never be functional. ++ */ ++ if (cpumask_weight(cpu_smt_mask(cpu)) > 1) ++ static_branch_enable_cpuslocked(&sched_smt_present); ++#endif + set_cpu_active(cpu, true); + + if (sched_smp_initialized) { +@@ -5871,22 +5883,6 @@ int sched_cpu_dying(unsigned int cpu) + } + #endif + +-#ifdef CONFIG_SCHED_SMT +-DEFINE_STATIC_KEY_FALSE(sched_smt_present); +- +-static void sched_init_smt(void) +-{ +- /* +- * We've enumerated all CPUs and will assume that if any CPU +- * has SMT siblings, CPU0 will too. +- */ +- if (cpumask_weight(cpu_smt_mask(0)) > 1) +- static_branch_enable(&sched_smt_present); +-} +-#else +-static inline void sched_init_smt(void) { } +-#endif +- + void __init sched_init_smp(void) + { + sched_init_numa(); +@@ -5908,8 +5904,6 @@ void __init sched_init_smp(void) + init_sched_rt_class(); + init_sched_dl_class(); + +- sched_init_smt(); +- + sched_smp_initialized = true; + } + +diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c +index 2f0a0be4d344..9c219f7b0970 100644 +--- a/kernel/sched/fair.c ++++ b/kernel/sched/fair.c +@@ -6237,6 +6237,7 @@ static inline int find_idlest_cpu(struct sched_domain *sd, struct task_struct *p + } + + #ifdef CONFIG_SCHED_SMT ++DEFINE_STATIC_KEY_FALSE(sched_smt_present); + + static inline void set_idle_cores(int cpu, int val) + { +diff --git a/kernel/smp.c b/kernel/smp.c +index 084c8b3a2681..d86eec5f51c1 100644 +--- a/kernel/smp.c ++++ b/kernel/smp.c +@@ -584,6 +584,8 @@ void __init smp_init(void) + num_nodes, (num_nodes > 1 ? "s" : ""), + num_cpus, (num_cpus > 1 ? "s" : "")); + ++ /* Final decision about SMT support */ ++ cpu_smt_check_topology(); + /* Any cleanup work */ + smp_cpus_done(setup_max_cpus); + } +diff --git a/mm/memory.c b/mm/memory.c +index c5e87a3a82ba..0e356dd923c2 100644 +--- a/mm/memory.c ++++ b/mm/memory.c +@@ -1884,6 +1884,9 @@ int vm_insert_pfn_prot(struct vm_area_struct *vma, unsigned long addr, + if (addr < vma->vm_start || addr >= vma->vm_end) + return -EFAULT; + ++ if (!pfn_modify_allowed(pfn, pgprot)) ++ return -EACCES; ++ + track_pfn_insert(vma, &pgprot, __pfn_to_pfn_t(pfn, PFN_DEV)); + + ret = insert_pfn(vma, addr, __pfn_to_pfn_t(pfn, PFN_DEV), pgprot, +@@ -1919,6 +1922,9 @@ static int __vm_insert_mixed(struct vm_area_struct *vma, unsigned long addr, + + track_pfn_insert(vma, &pgprot, pfn); + ++ if (!pfn_modify_allowed(pfn_t_to_pfn(pfn), pgprot)) ++ return -EACCES; ++ + /* + * If we don't have pte special, then we have to use the pfn_valid() + * based VM_MIXEDMAP scheme (see vm_normal_page), and thus we *must* +@@ -1980,6 +1986,7 @@ static int remap_pte_range(struct mm_struct *mm, pmd_t *pmd, + { + pte_t *pte; + spinlock_t *ptl; ++ int err = 0; + + pte = pte_alloc_map_lock(mm, pmd, addr, &ptl); + if (!pte) +@@ -1987,12 +1994,16 @@ static int remap_pte_range(struct mm_struct *mm, pmd_t *pmd, + arch_enter_lazy_mmu_mode(); + do { + BUG_ON(!pte_none(*pte)); ++ if (!pfn_modify_allowed(pfn, prot)) { ++ err = -EACCES; ++ break; ++ } + set_pte_at(mm, addr, pte, pte_mkspecial(pfn_pte(pfn, prot))); + pfn++; + } while (pte++, addr += PAGE_SIZE, addr != end); + arch_leave_lazy_mmu_mode(); + pte_unmap_unlock(pte - 1, ptl); +- return 0; ++ return err; + } + + static inline int remap_pmd_range(struct mm_struct *mm, pud_t *pud, +@@ -2001,6 +2012,7 @@ static inline int remap_pmd_range(struct mm_struct *mm, pud_t *pud, + { + pmd_t *pmd; + unsigned long next; ++ int err; + + pfn -= addr >> PAGE_SHIFT; + pmd = pmd_alloc(mm, pud, addr); +@@ -2009,9 +2021,10 @@ static inline int remap_pmd_range(struct mm_struct *mm, pud_t *pud, + VM_BUG_ON(pmd_trans_huge(*pmd)); + do { + next = pmd_addr_end(addr, end); +- if (remap_pte_range(mm, pmd, addr, next, +- pfn + (addr >> PAGE_SHIFT), prot)) +- return -ENOMEM; ++ err = remap_pte_range(mm, pmd, addr, next, ++ pfn + (addr >> PAGE_SHIFT), prot); ++ if (err) ++ return err; + } while (pmd++, addr = next, addr != end); + return 0; + } +@@ -2022,6 +2035,7 @@ static inline int remap_pud_range(struct mm_struct *mm, p4d_t *p4d, + { + pud_t *pud; + unsigned long next; ++ int err; + + pfn -= addr >> PAGE_SHIFT; + pud = pud_alloc(mm, p4d, addr); +@@ -2029,9 +2043,10 @@ static inline int remap_pud_range(struct mm_struct *mm, p4d_t *p4d, + return -ENOMEM; + do { + next = pud_addr_end(addr, end); +- if (remap_pmd_range(mm, pud, addr, next, +- pfn + (addr >> PAGE_SHIFT), prot)) +- return -ENOMEM; ++ err = remap_pmd_range(mm, pud, addr, next, ++ pfn + (addr >> PAGE_SHIFT), prot); ++ if (err) ++ return err; + } while (pud++, addr = next, addr != end); + return 0; + } +@@ -2042,6 +2057,7 @@ static inline int remap_p4d_range(struct mm_struct *mm, pgd_t *pgd, + { + p4d_t *p4d; + unsigned long next; ++ int err; + + pfn -= addr >> PAGE_SHIFT; + p4d = p4d_alloc(mm, pgd, addr); +@@ -2049,9 +2065,10 @@ static inline int remap_p4d_range(struct mm_struct *mm, pgd_t *pgd, + return -ENOMEM; + do { + next = p4d_addr_end(addr, end); +- if (remap_pud_range(mm, p4d, addr, next, +- pfn + (addr >> PAGE_SHIFT), prot)) +- return -ENOMEM; ++ err = remap_pud_range(mm, p4d, addr, next, ++ pfn + (addr >> PAGE_SHIFT), prot); ++ if (err) ++ return err; + } while (p4d++, addr = next, addr != end); + return 0; + } +diff --git a/mm/mprotect.c b/mm/mprotect.c +index 625608bc8962..6d331620b9e5 100644 +--- a/mm/mprotect.c ++++ b/mm/mprotect.c +@@ -306,6 +306,42 @@ unsigned long change_protection(struct vm_area_struct *vma, unsigned long start, + return pages; + } + ++static int prot_none_pte_entry(pte_t *pte, unsigned long addr, ++ unsigned long next, struct mm_walk *walk) ++{ ++ return pfn_modify_allowed(pte_pfn(*pte), *(pgprot_t *)(walk->private)) ? ++ 0 : -EACCES; ++} ++ ++static int prot_none_hugetlb_entry(pte_t *pte, unsigned long hmask, ++ unsigned long addr, unsigned long next, ++ struct mm_walk *walk) ++{ ++ return pfn_modify_allowed(pte_pfn(*pte), *(pgprot_t *)(walk->private)) ? ++ 0 : -EACCES; ++} ++ ++static int prot_none_test(unsigned long addr, unsigned long next, ++ struct mm_walk *walk) ++{ ++ return 0; ++} ++ ++static int prot_none_walk(struct vm_area_struct *vma, unsigned long start, ++ unsigned long end, unsigned long newflags) ++{ ++ pgprot_t new_pgprot = vm_get_page_prot(newflags); ++ struct mm_walk prot_none_walk = { ++ .pte_entry = prot_none_pte_entry, ++ .hugetlb_entry = prot_none_hugetlb_entry, ++ .test_walk = prot_none_test, ++ .mm = current->mm, ++ .private = &new_pgprot, ++ }; ++ ++ return walk_page_range(start, end, &prot_none_walk); ++} ++ + int + mprotect_fixup(struct vm_area_struct *vma, struct vm_area_struct **pprev, + unsigned long start, unsigned long end, unsigned long newflags) +@@ -323,6 +359,19 @@ mprotect_fixup(struct vm_area_struct *vma, struct vm_area_struct **pprev, + return 0; + } + ++ /* ++ * Do PROT_NONE PFN permission checks here when we can still ++ * bail out without undoing a lot of state. This is a rather ++ * uncommon case, so doesn't need to be very optimized. ++ */ ++ if (arch_has_pfn_modify_check() && ++ (vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) && ++ (newflags & (VM_READ|VM_WRITE|VM_EXEC)) == 0) { ++ error = prot_none_walk(vma, start, end, newflags); ++ if (error) ++ return error; ++ } ++ + /* + * If we make a private mapping writable we increase our commit; + * but (without finer accounting) cannot reduce our commit if we +diff --git a/mm/swapfile.c b/mm/swapfile.c +index 2cc2972eedaf..18185ae4f223 100644 +--- a/mm/swapfile.c ++++ b/mm/swapfile.c +@@ -2909,6 +2909,35 @@ static int claim_swapfile(struct swap_info_struct *p, struct inode *inode) + return 0; + } + ++ ++/* ++ * Find out how many pages are allowed for a single swap device. There ++ * are two limiting factors: ++ * 1) the number of bits for the swap offset in the swp_entry_t type, and ++ * 2) the number of bits in the swap pte, as defined by the different ++ * architectures. ++ * ++ * In order to find the largest possible bit mask, a swap entry with ++ * swap type 0 and swap offset ~0UL is created, encoded to a swap pte, ++ * decoded to a swp_entry_t again, and finally the swap offset is ++ * extracted. ++ * ++ * This will mask all the bits from the initial ~0UL mask that can't ++ * be encoded in either the swp_entry_t or the architecture definition ++ * of a swap pte. ++ */ ++unsigned long generic_max_swapfile_size(void) ++{ ++ return swp_offset(pte_to_swp_entry( ++ swp_entry_to_pte(swp_entry(0, ~0UL)))) + 1; ++} ++ ++/* Can be overridden by an architecture for additional checks. */ ++__weak unsigned long max_swapfile_size(void) ++{ ++ return generic_max_swapfile_size(); ++} ++ + static unsigned long read_swap_header(struct swap_info_struct *p, + union swap_header *swap_header, + struct inode *inode) +@@ -2944,22 +2973,7 @@ static unsigned long read_swap_header(struct swap_info_struct *p, + p->cluster_next = 1; + p->cluster_nr = 0; + +- /* +- * Find out how many pages are allowed for a single swap +- * device. There are two limiting factors: 1) the number +- * of bits for the swap offset in the swp_entry_t type, and +- * 2) the number of bits in the swap pte as defined by the +- * different architectures. In order to find the +- * largest possible bit mask, a swap entry with swap type 0 +- * and swap offset ~0UL is created, encoded to a swap pte, +- * decoded to a swp_entry_t again, and finally the swap +- * offset is extracted. This will mask all the bits from +- * the initial ~0UL mask that can't be encoded in either +- * the swp_entry_t or the architecture definition of a +- * swap pte. +- */ +- maxpages = swp_offset(pte_to_swp_entry( +- swp_entry_to_pte(swp_entry(0, ~0UL)))) + 1; ++ maxpages = max_swapfile_size(); + last_page = swap_header->info.last_page; + if (!last_page) { + pr_warn("Empty swap-file\n"); +diff --git a/tools/arch/x86/include/asm/cpufeatures.h b/tools/arch/x86/include/asm/cpufeatures.h +index 5701f5cecd31..64aaa3f5f36c 100644 +--- a/tools/arch/x86/include/asm/cpufeatures.h ++++ b/tools/arch/x86/include/asm/cpufeatures.h +@@ -219,6 +219,7 @@ + #define X86_FEATURE_IBPB ( 7*32+26) /* Indirect Branch Prediction Barrier */ + #define X86_FEATURE_STIBP ( 7*32+27) /* Single Thread Indirect Branch Predictors */ + #define X86_FEATURE_ZEN ( 7*32+28) /* "" CPU is AMD family 0x17 (Zen) */ ++#define X86_FEATURE_L1TF_PTEINV ( 7*32+29) /* "" L1TF workaround PTE inversion */ + + /* Virtualization flags: Linux defined, word 8 */ + #define X86_FEATURE_TPR_SHADOW ( 8*32+ 0) /* Intel TPR Shadow */ +@@ -341,6 +342,7 @@ + #define X86_FEATURE_PCONFIG (18*32+18) /* Intel PCONFIG */ + #define X86_FEATURE_SPEC_CTRL (18*32+26) /* "" Speculation Control (IBRS + IBPB) */ + #define X86_FEATURE_INTEL_STIBP (18*32+27) /* "" Single Thread Indirect Branch Predictors */ ++#define X86_FEATURE_FLUSH_L1D (18*32+28) /* Flush L1D cache */ + #define X86_FEATURE_ARCH_CAPABILITIES (18*32+29) /* IA32_ARCH_CAPABILITIES MSR (Intel) */ + #define X86_FEATURE_SPEC_CTRL_SSBD (18*32+31) /* "" Speculative Store Bypass Disable */ + +@@ -373,5 +375,6 @@ + #define X86_BUG_SPECTRE_V1 X86_BUG(15) /* CPU is affected by Spectre variant 1 attack with conditional branches */ + #define X86_BUG_SPECTRE_V2 X86_BUG(16) /* CPU is affected by Spectre variant 2 attack with indirect branches */ + #define X86_BUG_SPEC_STORE_BYPASS X86_BUG(17) /* CPU is affected by speculative store bypass attack */ ++#define X86_BUG_L1TF X86_BUG(18) /* CPU is affected by L1 Terminal Fault */ + + #endif /* _ASM_X86_CPUFEATURES_H */