On Tue, Jan 10, 2023, Mingwei Zhang wrote:
Repeat the checking of AMX component in xheader after xsavec when
s/xsavec/XSAVEC. Not sure about xheader, though it seems like that should be capitalized too.
IA32_XFD[18] is set. This check calibrates the functionality scope of
s/18/XTILEDATA
IA32_XFD: it does not intercept the XSAVE state management.
I didn't follow this. Is this basically saying "Verify XTILEDATA is saved by XSAVEC even when disabled via IA32_XFD"?
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@google.com
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
s/Bit 18/XTILEDATA
* remains the same even when IA32_XFD disables amx tiledata.
I would phrase this as "even when AMX tile data is disabled via IA32_XFD". Software disables AMX, IA32_XFD is the mechanic by which that is done.
*/- 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);
Same feedback about using !(...) and unnecessary "== x".
- GUEST_SYNC(6); GUEST_ASSERT(rdmsr(MSR_IA32_XFD) == XFEATURE_MASK_XTILEDATA); set_tilecfg(amx_cfg);
-- 2.39.0.314.g84b9a713c41-goog