KVM: selftests: Add check of CR0.TS in the #NM handler in amx_test

Be extra paranoid and assert that CR0.TS is clear when verifying the #NM
in the AMX test is due to the expected XFeature Disable error, i.e. that
the #NM isn't due to CR0.TS=1.

Signed-off-by: Mingwei Zhang <mizhang@google.com>
Link: https://lore.kernel.org/r/20230221163655.920289-6-mizhang@google.com
[sean: reword changelog to make it clear this is pure paranoia]
Signed-off-by: Sean Christopherson <seanjc@google.com>

diff --git a/tools/testing/selftests/kvm/x86_64/amx_test.c b/tools/testing/selftests/kvm/x86_64/amx_test.c
index 34cf6f253c1335fd97b9329c84efa1ca2eed7a5e..95a30611e03e5eb6e87168df2d7ccac2e710223d 100644 (file)
--- a/tools/testing/selftests/kvm/x86_64/amx_test.c
+++ b/tools/testing/selftests/kvm/x86_64/amx_test.c
@@ -216,6 +216,7 @@ void guest_nm_handler(struct ex_regs *regs)
 {
        /* Check if #NM is triggered by XFEATURE_MASK_XTILEDATA */
        GUEST_SYNC(7);
+       GUEST_ASSERT(!(get_cr0() & X86_CR0_TS));
        GUEST_ASSERT(rdmsr(MSR_IA32_XFD_ERR) == XFEATURE_MASK_XTILEDATA);
        GUEST_SYNC(8);
        GUEST_ASSERT(rdmsr(MSR_IA32_XFD_ERR) == XFEATURE_MASK_XTILEDATA);