[PATCH v3 09/57] KVM: selftests: Verify KVM stuffs runtime CPUID OS bits on CR4 writes

[Sean Christopherson <seanjc@google.com>]

Extend x86's set sregs test to verify that KVM sets/clears OSXSAVE and
OSKPKE according to CR4.XSAVE and CR4.PKE respectively.  For performance
reasons, KVM is responsible for emulating the architectural behavior of
the OS CPUID bits tracking CR4.

Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 tools/testing/selftests/kvm/x86_64/set_sregs_test.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/tools/testing/selftests/kvm/x86_64/set_sregs_test.c b/tools/testing/selftests/kvm/x86_64/set_sregs_test.c
index 96fd690d479a..f4095a3d1278 100644
--- a/tools/testing/selftests/kvm/x86_64/set_sregs_test.c
+++ b/tools/testing/selftests/kvm/x86_64/set_sregs_test.c
@@ -85,6 +85,16 @@ static void test_cr_bits(struct kvm_vcpu *vcpu, uint64_t cr4)
 	rc = _vcpu_sregs_set(vcpu, &sregs);
 	TEST_ASSERT(!rc, "Failed to set supported CR4 bits (0x%lx)", cr4);
 
+	TEST_ASSERT(!!(sregs.cr4 & X86_CR4_OSXSAVE) ==
+		    (vcpu->cpuid && vcpu_cpuid_has(vcpu, X86_FEATURE_OSXSAVE)),
+		    "KVM didn't %s OSXSAVE in CPUID as expected",
+		    (sregs.cr4 & X86_CR4_OSXSAVE) ? "set" : "clear");
+
+	TEST_ASSERT(!!(sregs.cr4 & X86_CR4_PKE) ==
+		    (vcpu->cpuid && vcpu_cpuid_has(vcpu, X86_FEATURE_OSPKE)),
+		    "KVM didn't %s OSPKE in CPUID as expected",
+		    (sregs.cr4 & X86_CR4_PKE) ? "set" : "clear");
+
 	vcpu_sregs_get(vcpu, &sregs);
 	TEST_ASSERT(sregs.cr4 == cr4, "sregs.CR4 (0x%llx) != CR4 (0x%lx)",
 		    sregs.cr4, cr4);
-- 
2.47.0.338.g60cca15819-goog