Re: [PATCH] KVM: X86: Allow userspace to define the microcode version

Borislav Petkov
2018-04-23T12:59:19Z

On Wed, Apr 18, 2018 at 12:36:37PM +0200, Paolo Bonzini wrote:
> On 18/04/2018 11:03, Eduardo Habkost wrote:
> >>> QEMU setting ucode_rev automatically using the host value when
> >>> using "-cpu host" (with no need for explicit ucode_rev option)
> >>> makes sense to me.
> >> QEMU can't get the host value by rdmsr MSR_IA32_UCODE_REV directly
> >> since rdmsr will #GP when ring !=0, any idea?
> > By looking at kvm_get_msr_feature(), it looks like
> > ioctl(system_fd, KVM_GET_MSRS) would return the host MSR value
> > for us.
>
> Yes, that's exactly what it was introduced for (together with other MSRs
> including VMX capabilities).

Can't qemu do:

grep microcode /proc/cpuinfo | awk '{ print $3 }' | head -n 1

?

:)

--
Regards/Gruss,
Boris.

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