[PATCH v3 3/5] KVM: x86: SVM: Pass through shadow stack MSRs

[John Allen <john.allen@amd.com>]

If kvm supports shadow stack, pass through shadow stack MSRs to improve
guest performance.

Signed-off-by: John Allen <john.allen@amd.com>
---
 arch/x86/kvm/svm/svm.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index a027d3c37181..82cde3578c96 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -838,6 +838,18 @@ static void svm_recalc_msr_intercepts(struct kvm_vcpu *vcpu)
 	svm_set_intercept_for_msr(vcpu, MSR_IA32_SYSENTER_ESP, MSR_TYPE_RW,
 				  guest_cpuid_is_intel_compatible(vcpu));
 
+	if (kvm_cpu_cap_has(X86_FEATURE_SHSTK)) {
+		bool shstk_enabled = guest_cpu_cap_has(vcpu, X86_FEATURE_SHSTK);
+
+		svm_set_intercept_for_msr(vcpu, MSR_IA32_U_CET, MSR_TYPE_RW, !shstk_enabled);
+		svm_set_intercept_for_msr(vcpu, MSR_IA32_S_CET, MSR_TYPE_RW, !shstk_enabled);
+		svm_set_intercept_for_msr(vcpu, MSR_IA32_PL0_SSP, MSR_TYPE_RW, !shstk_enabled);
+		svm_set_intercept_for_msr(vcpu, MSR_IA32_PL1_SSP, MSR_TYPE_RW, !shstk_enabled);
+		svm_set_intercept_for_msr(vcpu, MSR_IA32_PL2_SSP, MSR_TYPE_RW, !shstk_enabled);
+		svm_set_intercept_for_msr(vcpu, MSR_IA32_PL3_SSP, MSR_TYPE_RW, !shstk_enabled);
+		svm_set_intercept_for_msr(vcpu, MSR_IA32_INT_SSP_TAB, MSR_TYPE_RW, !shstk_enabled);
+	}
+
 	if (sev_es_guest(vcpu->kvm))
 		sev_es_recalc_msr_intercepts(vcpu);
 
-- 
2.34.1