Re: [PATCH v5 18/19] KVM:nVMX: Refine error code injection to nested VM

[Yang, Weijiang]

On 8/5/2023 5:38 AM, Sean Christopherson wrote:
> This is not "refinement", this is full on supporting a new nVMX feature.  Please
> phrase the shortlog accordingly, e.g. something like this (it's not very good,
> but it's a start).
>
>    KVM: nVMX: Add support for exposing "No PM H/W error code checks" to L1
>
> Regarding shortlog, please update all of them in this series to put a space after
> the colon, i.e. "KVM: VMX:" and "KVM: x86:", not "KVM:x86:".
OK, will update this part.
> >   static void nested_vmx_setup_cr_fixed(struct nested_vmx_msrs *msrs)
> > diff --git a/arch/x86/kvm/vmx/nested.h b/arch/x86/kvm/vmx/nested.h
> > index 96952263b029..1884628294e4 100644
> > --- a/arch/x86/kvm/vmx/nested.h
> > +++ b/arch/x86/kvm/vmx/nested.h
> > @@ -284,6 +284,13 @@ static inline bool nested_cr4_valid(struct kvm_vcpu *vcpu, unsigned long val)
> >   	       __kvm_is_valid_cr4(vcpu, val);
> >   }
> >   
> > +static inline bool nested_cpu_has_no_hw_errcode(struct kvm_vcpu *vcpu)
> > +{
> > +	struct vcpu_vmx *vmx = to_vmx(vcpu);
> > +
> > +	return vmx->nested.msrs.basic & VMX_BASIC_NO_HW_ERROR_CODE;
> The "CC" part of my suggestion is critical to this being sane.  As is, this reads
> "nested CPU has no hardware error code", which is not even remotely close to the
> truth.
Understood, I was not aware of the essence of "CC".
> static inline bool nested_cpu_has_no_hw_errcode_cc(struct kvm_vcpu *vcpu)
> {
> 	return to_vmx(vcpu)->nested.msrs.basic & VMX_BASIC_NO_HW_ERROR_CODE_CC;
> }
>
> [*] https://lore.kernel.org/all/ZJ7vyBw1nbTBOfuf@xxxxxxxxxx