Re: [PATCH 15/19] kvm: x86: Save and restore guest XFD_ERR properly

Paolo Bonzini
2021-12-11T01:31:52Z

On 12/11/21 01:10, Thomas Gleixner wrote:
> 2) When the guest triggers #NM is takes an VMEXIT and the host
> does:
>
> rdmsrl(MSR_XFD_ERR, vcpu->arch.guest_fpu.xfd_err);
>
> injects the #NM and goes on.
>
> 3) When the guest writes to MSR_XFD_ERR it takes an VMEXIT and
> the host does:
>
> vcpu->arch.guest_fpu.xfd_err = msrval;
> wrmsrl(MSR_XFD_ERR, msrval);

No wrmsrl here I think, the host value is 0 and should stay so. Instead
the wrmsrl will happen the next time the VCPU loop is entred.

Paolo