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KVM: selftests: Verify XTILE_DATA in XSTATE isn't affected by IA32_XFD

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Add asserts to verify the XSTATE metadata for XTILE_DATA isn't affected
by disabling AMX tile data via IA32_XFD.  XFD doesn't intercept XSAVE,
it only prevents setting bits in XCR0, i.e. regardless of XFD, AMX state
is managed by XSAVE/XRSTOR as long as the corresponding bits are set XCR0.

Signed-off-by: Mingwei Zhang <mizhang@google.com>
Link: https://lore.kernel.org/r/20230221163655.920289-9-mizhang@google.com
[sean: massage changelog]
Signed-off-by: Sean Christopherson <seanjc@google.com>
This commit is contained in:
Mingwei Zhang 2023-02-21 16:36:50 +00:00 committed by Sean Christopherson
parent 9cbd9aaa67
commit bfc5afc37c
1 changed files with 10 additions and 0 deletions
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10
tools/testing/selftests/kvm/x86_64/amx_test.c
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@ -201,6 +201,16 @@ static void __attribute__((__flatten__)) guest_code(struct tile_config *amx_cfg,
/* xfd=0x40000, disable amx tiledata */
wrmsr(MSR_IA32_XFD, XFEATURE_MASK_XTILEDATA);
/*
* XTILEDATA is cleared in xstate_bv but set in xcomp_bv, this property
* remains the same even when amx tiledata is disabled by IA32_XFD.
*/
xstate->header.xstate_bv = XFEATURE_MASK_XTILEDATA;
__xsavec(xstate, XFEATURE_MASK_XTILEDATA);
GUEST_ASSERT(!(xstate->header.xstate_bv & XFEATURE_MASK_XTILEDATA));
GUEST_ASSERT((xstate->header.xcomp_bv & XFEATURE_MASK_XTILEDATA));
GUEST_SYNC(6);
GUEST_ASSERT(rdmsr(MSR_IA32_XFD) == XFEATURE_MASK_XTILEDATA);
set_tilecfg(amx_cfg);