Re: [gentoo-user] KVM on AMD ... why doesn't it just work?

[Kerin Millar <kerframil@fastmail.co.uk>]

On 02/10/2013 13:27, Stefan G. Weichinger wrote:
>
> I try to set up KVM/QEMU on that new and shiny AMD server
>
> 24 cores of Opteron:
>
> processor	: 23
> vendor_id	: AuthenticAMD
> cpu family	: 21
> model		: 2
> model name	: AMD Opteron(tm) Processor 6344
>
> nice
>
> I want gentoo-sources-3.10.7 (stable and long term supported) or
> 3.10.7-r1 (not yet on the machine).
>
> I don't get /dev/kvm :-(
>
> Right now I want this as a module "kvm_amd" or so.
>
> # zgrep -i kvm /proc/config.gz
> CONFIG_HAVE_KVM=y
> CONFIG_HAVE_KVM_IRQCHIP=y
> CONFIG_HAVE_KVM_IRQ_ROUTING=y
> CONFIG_HAVE_KVM_EVENTFD=y
> CONFIG_KVM_APIC_ARCHITECTURE=y
> CONFIG_KVM_MMIO=y
> CONFIG_KVM_ASYNC_PF=y
> CONFIG_HAVE_KVM_MSI=y
> CONFIG_HAVE_KVM_CPU_RELAX_INTERCEPT=y
> CONFIG_KVM=m
> CONFIG_KVM_INTEL=m
> CONFIG_KVM_AMD=m
>
> I compile the kernel with Canek's kerninst-script (see other thread).
>
> kvm_amd does not load and gives me dozens of:
>
> # dmesg | grep kvm  | head
> [   13.460423] kvm_amd: Unknown symbol kvm_rdpmc (err 0)
> [   13.460429] kvm_amd: Unknown symbol kvm_read_guest_page (err 0)
> [   13.460437] kvm_amd: Unknown symbol kvm_requeue_exception (err 0)
> [   13.460439] kvm_amd: Unknown symbol kvm_exit (err 0)
> [   13.460441] kvm_amd: Unknown symbol kvm_init (err 0)
> [   13.460444] kvm_amd: Unknown symbol kvm_enable_efer_bits (err 0)
> [   13.460448] kvm_amd: Unknown symbol kvm_fast_pio_out (err 0)
> [   13.460453] kvm_amd: Unknown symbol gfn_to_page (err 0)

Run "modinfo kvm kvm-amd" and check for discrepancies between the 
details of the two, especially regarding the vermagic field.

>
> *sigh*
>
> With the kernel booted I now do:
>
> cd /usr/src/linux
> make clean modules modules_install

I would suggest "make mrproper" to clean the source tree. Ensure that 
the .config has been backed up because it will be deleted as a result.

>
> and see if I can load the module(s) then.
>
> In general I am rather disappointed by the performance of this server. I
> expected way more *bang* for the bucks ...
>
> still unsure if that clocksource-topic might be relevant or if my kernel
> config is somehow stupid.
>
> Stefan

--Kerin