Re: [PATCH 25/30] KVM: nSVM: leave guest mode when clearing EFER.SVME

[Paolo Bonzini]

On 01/06/20 04:26, Krish Sadhukhan wrote:
> On 5/29/20 8:39 AM, Paolo Bonzini wrote:
>> According to the AMD manual, the effect of turning off EFER.SVME while a
>> guest is running is undefined. We make it leave guest mode immediately,
>> similar to the effect of clearing the VMX bit in MSR_IA32_FEAT_CTL.
> 
> I see that svm_set_efer() is called in enter_svm_guest_mode() and
> nested_svm_vmexit(). In the VMRUN path, we have already checked
> EFER.SVME in nested_vmcb_checks(). So if it was not set, we wouldn't
> come to enter_svm_guest_mode(). Your fix is only for the #VMEXIT path
> then ?

No, it's for KVM_SET_MSR.

Paolo