linux-kernel - [PATCH v2 21/23] KVM: selftests: Allow kvm_cpu_has

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Message-ID: <20251021074736.1324328-22-yosry.ahmed@linux.dev>
Date: Tue, 21 Oct 2025 07:47:34 +0000
From: Yosry Ahmed <yosry.ahmed@...ux.dev>
To: Sean Christopherson <seanjc@...gle.com>
Cc: Paolo Bonzini <pbonzini@...hat.com>,
	Jim Mattson <jmattson@...gle.com>,
	kvm@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Yosry Ahmed <yosry.ahmed@...ux.dev>
Subject: [PATCH v2 21/23] KVM: selftests: Allow kvm_cpu_has_ept() to be called on AMD CPUs

In preparation for generalizing the nested dirty logging test, checking
if either EPT or NPT is enabled will be needed. To avoid needing to gate
the kvm_cpu_has_ept() call by the CPU type, make sure the function
returns false if VMX is not available instead of trying to read VMX-only
MSRs.

No functional change intended.

Signed-off-by: Yosry Ahmed <yosry.ahmed@...ux.dev>
---
 tools/testing/selftests/kvm/lib/x86/vmx.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/tools/testing/selftests/kvm/lib/x86/vmx.c b/tools/testing/selftests/kvm/lib/x86/vmx.c
index 1a9743cabcf4b..b1f22e78aca1a 100644
--- a/tools/testing/selftests/kvm/lib/x86/vmx.c
+++ b/tools/testing/selftests/kvm/lib/x86/vmx.c
@@ -365,6 +365,9 @@ bool kvm_cpu_has_ept(void)
 {
 	uint64_t ctrl;
 
+	if (!kvm_cpu_has(X86_FEATURE_VMX))
+		return false;
+
 	ctrl = kvm_get_feature_msr(MSR_IA32_VMX_TRUE_PROCBASED_CTLS) >> 32;
 	if (!(ctrl & CPU_BASED_ACTIVATE_SECONDARY_CONTROLS))
 		return false;
-- 
2.51.0.869.ge66316f041-goog