Re: [PATCH] KVM: x86: Add three MSRs to the list of ignored MSRs

Paolo Bonzini
2016-04-14T14:43:03Z

On 14/04/2016 15:33, Radim Krčmář wrote:
> The main bug in KVM is that it allows the guest to think that it runs on
> CPU that isn't emulated: any CPU that has MSR_PLATFORM_INFO shouldn't
> be exposed in KVM.

That's all of them. f/m/s values and the model name are a useful
debugging tool. Considering that MSR_PLATFORM_INFO is hardly ever used,
it doesn't seem to be a great compromise.

The actual question is why the hell a graphics driver cares about it.

Paolo

> Incorrect use of CPU also is a userspace problem, so
> KVM could just pass this MSR for emulation to userspace.
> (Passing to userspace won't directly fix your problem, though)