Re: [PATCH v10 26/27] KVM: nVMX: Enable CET support for nested guest

[Yang, Weijiang]

On 5/2/2024 7:23 AM, Sean Christopherson wrote:
> On Sun, Feb 18, 2024, Yang Weijiang wrote:
> > @@ -2438,6 +2460,30 @@ static void prepare_vmcs02_early(struct vcpu_vmx *vmx, struct loaded_vmcs *vmcs0
> >   	}
> >   }
> >   
> > +static inline void cet_vmcs_fields_get(struct kvm_vcpu *vcpu, u64 *ssp,
> > +				       u64 *s_cet, u64 *ssp_tbl)
> > +{
> > +	if (guest_can_use(vcpu, X86_FEATURE_SHSTK)) {
> > +		*ssp = vmcs_readl(GUEST_SSP);
> > +		*s_cet = vmcs_readl(GUEST_S_CET);
> > +		*ssp_tbl = vmcs_readl(GUEST_INTR_SSP_TABLE);
> > +	} else if (guest_can_use(vcpu, X86_FEATURE_IBT)) {
> > +		*s_cet = vmcs_readl(GUEST_S_CET);
> > +	}
> Same comments about accessing S_CET, please do so in a dedicated path.

Will change it, thanks!

> > +}
> > +
> > +static inline void cet_vmcs_fields_put(struct kvm_vcpu *vcpu, u64 ssp,
> > +				       u64 s_cet, u64 ssp_tbl)
> This should probably use "set" instead of "put".  I can't think of a single case
> where KVM uses "put" to describe writing state, e.g. "put" is always used when
> putting a reference or unloading state.

Yes, "put" is not proper in this case, will change it.


> > +{
> > +	if (guest_can_use(vcpu, X86_FEATURE_SHSTK)) {
> > +		vmcs_writel(GUEST_SSP, ssp);
> > +		vmcs_writel(GUEST_S_CET, s_cet);
> > +		vmcs_writel(GUEST_INTR_SSP_TABLE, ssp_tbl);
> > +	} else if (guest_can_use(vcpu, X86_FEATURE_IBT)) {
> > +		vmcs_writel(GUEST_S_CET, s_cet);
> > +	}
> And here.

OK.