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

From: Yang, Weijiang
Date: Mon May 06 2024 - 05:26:08 EST


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.