[PATCH v3 09/13] KVM: selftests: x86: Assert that XTILE is XSAVE-enabled

From: Mingwei Zhang
Date: Tue Feb 21 2023 - 11:38:10 EST


From: Aaron Lewis <aaronlewis@xxxxxxxxxx>

Assert that XTILE is XSAVE-enabled. check_xsave_supports_xtile() doesn't
actually check anything since its return value is not used. Add the
intended assert.

Opportunistically, move the assert to a more appropriate location:
immediately after XSETBV and remove check_xsave_supports_xtile().

Fixes: 5dc19f1c7dd3 ("KVM: selftests: Convert AMX test to use X86_PROPRETY_XXX")
Signed-off-by: Aaron Lewis <aaronlewis@xxxxxxxxxx>
Signed-off-by: Mingwei Zhang <mizhang@xxxxxxxxxx>
---
tools/testing/selftests/kvm/x86_64/amx_test.c | 7 +------
1 file changed, 1 insertion(+), 6 deletions(-)

diff --git a/tools/testing/selftests/kvm/x86_64/amx_test.c b/tools/testing/selftests/kvm/x86_64/amx_test.c
index 724e991ba814..d1fbf8936192 100644
--- a/tools/testing/selftests/kvm/x86_64/amx_test.c
+++ b/tools/testing/selftests/kvm/x86_64/amx_test.c
@@ -115,11 +115,6 @@ static inline void check_cpuid_xsave(void)
GUEST_ASSERT(this_cpu_has(X86_FEATURE_OSXSAVE));
}

-static bool check_xsave_supports_xtile(void)
-{
- return __xgetbv(0) & XFEATURE_MASK_XTILE;
-}
-
static void check_xtile_info(void)
{
GUEST_ASSERT(this_cpu_has_p(X86_PROPERTY_XSTATE_MAX_SIZE_XCR0));
@@ -166,6 +161,7 @@ static void init_regs(void)
xcr0 = __xgetbv(0);
xcr0 |= XFEATURE_MASK_XTILE;
__xsetbv(0x0, xcr0);
+ GUEST_ASSERT(__xgetbv(0) & XFEATURE_MASK_XTILE);
}

static void __attribute__((__flatten__)) guest_code(struct tile_config *amx_cfg,
@@ -174,7 +170,6 @@ static void __attribute__((__flatten__)) guest_code(struct tile_config *amx_cfg,
{
init_regs();
check_cpuid_xsave();
- check_xsave_supports_xtile();
check_xtile_info();
GUEST_SYNC(1);

--
2.39.2.637.g21b0678d19-goog