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

From: Borislav Petkov
Date: Mon Feb 26 2018 - 08:08:18 EST


On Mon, Feb 26, 2018 at 01:41:38PM +0100, Paolo Bonzini wrote:
> More like "-cpu foo,ucode_rev=0xdeadbeef". But in practice what would
> happen is one of the following:
>
> 1) "-cpu host" sets ucode_rev to the same value of the host, everyone
> else leaves it to zero as is now.
>
> 2) Only Amazon uses this feature and we ignore it. :)

I fear that that might get misused and we probably should consider some
trivial range checking and each qemu cpu model would have a valid range
or so.

Or we should better do that in kvm_set_msr_common directly... although
if we do it here, it would require kvm knowing about all those different
microcode revisions and qemu cpu models sounds better...

--
Regards/Gruss,
Boris.

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