Repeat the checking of AMX component in xheader after xsavec when IA32_XFD[18] is set. This check calibrates the functionality scope of IA32_XFD: it does not intercept the XSAVE state management. Regardless of the values in IA32_XFD, AMX component state will still be managed by XSAVE* and XRSTOR* as long as XCR[18:17] are set. Signed-off-by: Mingwei Zhang <mizhang@xxxxxxxxxx> --- tools/testing/selftests/kvm/x86_64/amx_test.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/tools/testing/selftests/kvm/x86_64/amx_test.c b/tools/testing/selftests/kvm/x86_64/amx_test.c index 18203e399e9d..9a80a59b64e6 100644 --- a/tools/testing/selftests/kvm/x86_64/amx_test.c +++ b/tools/testing/selftests/kvm/x86_64/amx_test.c @@ -235,6 +235,16 @@ static void __attribute__((__flatten__)) guest_code(struct tile_config *amx_cfg, /* xfd=0x40000, disable amx tiledata */ wrmsr(MSR_IA32_XFD, XFEATURE_MASK_XTILEDATA); + + /* + * Bit 18 is cleared in XSTATE_BV but set in XCOMP_BV, this property + * remains the same even when IA32_XFD disables amx tiledata. + */ + set_xstatebv(xsave_data, XFEATURE_MASK_XTILEDATA); + __xsavec(xsave_data, XFEATURE_MASK_XTILEDATA); + GUEST_ASSERT((get_xstatebv(xsave_data) & XFEATURE_MASK_XTILEDATA) == 0); + GUEST_ASSERT((get_xcompbv(xsave_data) & XFEATURE_MASK_XTILEDATA) == XFEATURE_MASK_XTILEDATA); + GUEST_SYNC(6); GUEST_ASSERT(rdmsr(MSR_IA32_XFD) == XFEATURE_MASK_XTILEDATA); set_tilecfg(amx_cfg); -- 2.39.0.314.g84b9a713c41-goog
