> >+ case MSR_IA32_FRED_RSP0 ... MSR_IA32_FRED_CONFIG:
> >+ /* FRED MSRs should be passthrough to FRED guests only */
>
> This comment sounds weird. It sounds like the code will be something like:
> if guest supports FRED
> return true
> else
> return false
>
> how about "FRED MSRs are pass-thru'd to guests which enumerate FRED"?
>
> Or to align with above comment for LBR MSRs, just say
>
> /* FRED MSRs. These are handled in vmx_vcpu_config_fred_after_set_cpuid() */
>
Maybe both to not confuse people at all 😊
> >+ return true;
> > }
> >
> > r = possible_passthrough_msr_slot(msr) != -ENOENT; @@ -7774,10
> >+7777,12 @@ static void update_intel_pt_cfg(struct kvm_vcpu *vcpu)
> >static void vmx_vcpu_config_fred_after_set_cpuid(struct kvm_vcpu *vcpu)
> >{
> > struct vcpu_vmx *vmx = to_vmx(vcpu);
> >+ bool fred_enumerated;
> >
> > kvm_governed_feature_check_and_set(vcpu, X86_FEATURE_FRED);
> >+ fred_enumerated = guest_can_use(vcpu, X86_FEATURE_FRED);
> >
> >- if (guest_can_use(vcpu, X86_FEATURE_FRED)) {
> >+ if (fred_enumerated) {
> > vm_entry_controls_setbit(vmx, VM_ENTRY_LOAD_IA32_FRED);
> > secondary_vm_exit_controls_setbit(vmx,
> >
> SECONDARY_VM_EXIT_SAVE_IA32_FRED | @@ -7788,6 +7793,16 @@
> >static void vmx_vcpu_config_fred_after_set_cpuid(struct kvm_vcpu *vcpu)
> >
> SECONDARY_VM_EXIT_SAVE_IA32_FRED |
> >
> SECONDARY_VM_EXIT_LOAD_IA32_FRED);
> > }
> >+
> >+ vmx_set_intercept_for_msr(vcpu, MSR_IA32_FRED_RSP0,
> MSR_TYPE_RW, !fred_enumerated);
> >+ vmx_set_intercept_for_msr(vcpu, MSR_IA32_FRED_RSP1,
> MSR_TYPE_RW, !fred_enumerated);
> >+ vmx_set_intercept_for_msr(vcpu, MSR_IA32_FRED_RSP2,
> MSR_TYPE_RW, !fred_enumerated);
> >+ vmx_set_intercept_for_msr(vcpu, MSR_IA32_FRED_RSP3,
> MSR_TYPE_RW, !fred_enumerated);
> >+ vmx_set_intercept_for_msr(vcpu, MSR_IA32_FRED_STKLVLS,
> MSR_TYPE_RW, !fred_enumerated);
> >+ vmx_set_intercept_for_msr(vcpu, MSR_IA32_FRED_SSP1,
> MSR_TYPE_RW, !fred_enumerated);
> >+ vmx_set_intercept_for_msr(vcpu, MSR_IA32_FRED_SSP2,
> MSR_TYPE_RW, !fred_enumerated);
> >+ vmx_set_intercept_for_msr(vcpu, MSR_IA32_FRED_SSP3,
> MSR_TYPE_RW, !fred_enumerated);
> >+ vmx_set_intercept_for_msr(vcpu, MSR_IA32_FRED_CONFIG, MSR_TYPE_RW,
> >+!fred_enumerated);
>
> Use a for-loop here? e.g.,
> for (i = MSR_IA32_FRED_RSP0; i <= MSR_IA32_FRED_CONFIG; i++)
> > }
Yeah, let me try.
