KVM: selftests: Check for APIC access virtualization support in said test

Not all CPUs that support VMX necessarily support the "virtualize APIC
accesses" secondary processor-based VM-execution control. For example,
some Zhaoxin CPUs lack this feature. Add a capability check before
running the test to properly skip on unsupported hardware instead of
failing.

Carve out the guts of kvm_cpu_has_ept() into a generic helper and use said
helper to provide kvm_cpu_has_vmx_apic_access_virt().

Signed-off-by: Frank Zhu <frankzhu@zhaoxin.com>
Link: https://patch.msgid.link/20260910115414.3015260-10-ewanhai-oc@zhaoxin.com
[sean: add a helper instead of copy+pasting kvm_cpu_has_ept()]
Signed-off-by: Sean Christopherson <seanjc@google.com>

3 files changed, 19 insertions, 8 deletions

diff --git a/tools/testing/selftests/kvm/include/x86/vmx.h b/tools/testing/selftests/kvm/include/x86/vmx.h
index ca67a618b68f..8fd97434eee5 100644
--- a/tools/testing/selftests/kvm/include/x86/vmx.h
+++ b/tools/testing/selftests/kvm/include/x86/vmx.h
@@ -503,7 +503,18 @@ void load_vmcs(struct vmx_pages *vmx);
 
 bool ept_1g_pages_supported(void);
 
-bool kvm_cpu_has_ept(void);
+bool kvm_cpu_has_secondary_exec_control(u32 ctrl);
+
+static inline bool kvm_cpu_has_ept(void)
+{
+	return kvm_cpu_has_secondary_exec_control(SECONDARY_EXEC_ENABLE_EPT);
+}
+
+static inline bool kvm_cpu_has_vmx_virtualize_apic_accesses(void)
+{
+	return kvm_cpu_has_secondary_exec_control(SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES);
+}
+
 void vm_enable_ept(struct kvm_vm *vm);
 void prepare_virtualize_apic_accesses(struct vmx_pages *vmx, struct kvm_vm *vm);
 
diff --git a/tools/testing/selftests/kvm/lib/x86/vmx.c b/tools/testing/selftests/kvm/lib/x86/vmx.c
index 6a53c8ce3b3c..5a06746ebea4 100644
--- a/tools/testing/selftests/kvm/lib/x86/vmx.c
+++ b/tools/testing/selftests/kvm/lib/x86/vmx.c
@@ -422,19 +422,19 @@ void prepare_vmcs(struct vmx_pages *vmx, void *guest_rip)
 	init_vmcs_guest_state(guest_rip, vmx->stack);
 }
 
-bool kvm_cpu_has_ept(void)
+bool kvm_cpu_has_secondary_exec_control(u32 ctrl)
 {
-	u64 ctrl;
+	u64 ctrl_msr;
 
 	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))
+	ctrl_msr = kvm_get_feature_msr(MSR_IA32_VMX_TRUE_PROCBASED_CTLS) >> 32;
+	if (!(ctrl_msr & CPU_BASED_ACTIVATE_SECONDARY_CONTROLS))
 		return false;
 
-	ctrl = kvm_get_feature_msr(MSR_IA32_VMX_PROCBASED_CTLS2) >> 32;
-	return ctrl & SECONDARY_EXEC_ENABLE_EPT;
+	ctrl_msr = kvm_get_feature_msr(MSR_IA32_VMX_PROCBASED_CTLS2) >> 32;
+	return ctrl_msr & ctrl;
 }
 
 void prepare_virtualize_apic_accesses(struct vmx_pages *vmx, struct kvm_vm *vm)
diff --git a/tools/testing/selftests/kvm/x86/vmx_apic_access_test.c b/tools/testing/selftests/kvm/x86/vmx_apic_access_test.c
index d6373c414d18..1d7a529c8297 100644
--- a/tools/testing/selftests/kvm/x86/vmx_apic_access_test.c
+++ b/tools/testing/selftests/kvm/x86/vmx_apic_access_test.c
@@ -77,7 +77,7 @@ int main(int argc, char *argv[])
 	struct kvm_vcpu *vcpu;
 	struct kvm_vm *vm;
 
-	TEST_REQUIRE(kvm_cpu_has(X86_FEATURE_VMX));
+	TEST_REQUIRE(kvm_cpu_has_vmx_virtualize_apic_accesses());
 
 	vm = vm_create_with_one_vcpu(&vcpu, l1_guest_code);