linux-kernel - [PATCH v4 15/21] KVM: selftests: Allow kvm_cpu_has

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Message-ID: <20251230230150.4150236-16-seanjc@google.com>
Date: Tue, 30 Dec 2025 15:01:44 -0800
From: Sean Christopherson <seanjc@...gle.com>
To: Paolo Bonzini <pbonzini@...hat.com>, Marc Zyngier <maz@...nel.org>, 
	Oliver Upton <oupton@...nel.org>, Tianrui Zhao <zhaotianrui@...ngson.cn>, 
	Bibo Mao <maobibo@...ngson.cn>, Huacai Chen <chenhuacai@...nel.org>, 
	Anup Patel <anup@...infault.org>, Paul Walmsley <pjw@...nel.org>, 
	Palmer Dabbelt <palmer@...belt.com>, Albert Ou <aou@...s.berkeley.edu>, 
	Christian Borntraeger <borntraeger@...ux.ibm.com>, Janosch Frank <frankja@...ux.ibm.com>, 
	Claudio Imbrenda <imbrenda@...ux.ibm.com>, Sean Christopherson <seanjc@...gle.com>
Cc: kvm@...r.kernel.org, linux-arm-kernel@...ts.infradead.org, 
	kvmarm@...ts.linux.dev, loongarch@...ts.linux.dev, 
	kvm-riscv@...ts.infradead.org, linux-riscv@...ts.infradead.org, 
	linux-kernel@...r.kernel.org, Yosry Ahmed <yosry.ahmed@...ux.dev>
Subject: [PATCH v4 15/21] KVM: selftests: Allow kvm_cpu_has_ept() to be called
 on AMD CPUs

From: Yosry Ahmed <yosry.ahmed@...ux.dev>

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>
Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
 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 448a63457467..c87b340362a9 100644
--- a/tools/testing/selftests/kvm/lib/x86/vmx.c
+++ b/tools/testing/selftests/kvm/lib/x86/vmx.c
@@ -377,6 +377,9 @@ 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;
-- 
2.52.0.351.gbe84eed79e-goog