From 8ae01bf64caaea5562f3af40a2fbe404a1e79403 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Thu, 3 Oct 2024 16:43:32 -0700 Subject: [PATCH] KVM: selftests: Verify XCR0 can be "downgraded" and "upgraded" Now that KVM selftests enable all supported XCR0 features by default, add a testcase to the XCR0 vs. CPUID test to verify that the guest can disable everything except the legacy FPU in XCR0, and then re-enable the full feature set, which is kinda sorta what the test did before XCR0 was setup by default. Reviewed-by: Vitaly Kuznetsov Link: https://lore.kernel.org/r/20241003234337.273364-7-seanjc@google.com Signed-off-by: Sean Christopherson --- tools/testing/selftests/kvm/x86_64/xcr0_cpuid_test.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/tools/testing/selftests/kvm/x86_64/xcr0_cpuid_test.c b/tools/testing/selftests/kvm/x86_64/xcr0_cpuid_test.c index a4aecdc77da5..c8a5c5e51661 100644 --- a/tools/testing/selftests/kvm/x86_64/xcr0_cpuid_test.c +++ b/tools/testing/selftests/kvm/x86_64/xcr0_cpuid_test.c @@ -79,6 +79,11 @@ static void guest_code(void) ASSERT_ALL_OR_NONE_XFEATURE(supported_xcr0, XFEATURE_MASK_XTILE); + vector = xsetbv_safe(0, XFEATURE_MASK_FP); + __GUEST_ASSERT(!vector, + "Expected success on XSETBV(FP), got vector '0x%x'", + vector); + vector = xsetbv_safe(0, supported_xcr0); __GUEST_ASSERT(!vector, "Expected success on XSETBV(0x%lx), got vector '0x%x'", -- 2.50.1