Re: [PATCH v4 2/8] KVM: x86: nSVM: Cache and validate vmcb12 g_pat

[Yosry Ahmed]

February 21, 2026 at 12:26 AM, "Jim Mattson" <jmattson@xxxxxxxxxx> wrote:
> 
> On Thu, Feb 12, 2026 at 4:22 PM Yosry Ahmed <> wrote:
> 
> > 
> > @@ -2006,13 +2012,16 @@ static int svm_set_nested_state(struct kvm_vcpu *vcpu,
> > 
> >  /*
> >  * Validate host state saved from before VMRUN (see
> >  - * nested_svm_check_permissions).
> >  + * nested_svm_check_permissions). Note that the g_pat field is not
> >  + * validated, because (a) it may have been clobbered by SMM before
> >  + * KVM_GET_NESTED_STATE, and (b) it is not loaded at emulated
> >  + * #VMEXIT.
> > 
> >  (b) here means that svm_copy_vmrun_state() does not copy it to vmcb01,
> >  and the value is restored by KVM_SET_MSRS, right?
> > 
> Actually, (b) refers to the open-coded block of assignments in
> nested_svm_vmexit() under the comment:
> 
>  /*
>  * Restore processor state that had been saved in vmcb01
>  */
>

Yeah IIUC it's the same thing, we migrate them and copy them here to vmcb01 so that we can restore them in nested_svm_vmexit().