linux-kernel - [PATCH 2/2] KVM: SVM: Simplify MSR interception logic for IA32

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Message-ID: <20250612081947.94081-3-chao.gao@intel.com>
Date: Thu, 12 Jun 2025 01:19:47 -0700
From: Chao Gao <chao.gao@...el.com>
To: linux-kernel@...r.kernel.org,
	kvm@...r.kernel.org
Cc: seanjc@...gle.com,
	pbonzini@...hat.com,
	dapeng1.mi@...ux.intel.com,
	Chao Gao <chao.gao@...el.com>
Subject: [PATCH 2/2] KVM: SVM: Simplify MSR interception logic for IA32_XSS MSR

Use svm_set_intercept_for_msr() directly to configure IA32_XSS MSR
interception, ensuring consistency with other cases where MSRs are
intercepted depending on guest caps and CPUIDs.

No functional change intended.

Signed-off-by: Chao Gao <chao.gao@...el.com>
---
With this patch applied, svm_enable_intercept_for_msr() has no user.
Should it be removed?
---
 arch/x86/kvm/svm/sev.c | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 6282c2930cda..504e8a87644a 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -4371,11 +4371,9 @@ void sev_es_recalc_msr_intercepts(struct kvm_vcpu *vcpu)
 	 * XSAVES being exposed to the guest so that KVM can at least honor
 	 * guest CPUID for RDMSR and WRMSR.
 	 */
-	if (guest_cpu_cap_has(vcpu, X86_FEATURE_XSAVES) &&
-	    guest_cpuid_has(vcpu, X86_FEATURE_XSAVES))
-		svm_disable_intercept_for_msr(vcpu, MSR_IA32_XSS, MSR_TYPE_RW);
-	else
-		svm_enable_intercept_for_msr(vcpu, MSR_IA32_XSS, MSR_TYPE_RW);
+	svm_set_intercept_for_msr(vcpu, MSR_IA32_XSS, MSR_TYPE_RW,
+				  !guest_cpu_cap_has(vcpu, X86_FEATURE_XSAVES) ||
+				  !guest_cpuid_has(vcpu, X86_FEATURE_XSAVES));
 }
 
 void sev_vcpu_after_set_cpuid(struct vcpu_svm *svm)
-- 
2.47.1