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KVM: selftests: Enable checking on xcomp_bv in amx_test

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After tilerelease instruction, AMX tiles are in INIT state. According to
Intel SDM vol 1. 13.10: "If RFBM[i] = 1, XSTATE_BV[i] is set to the
value of XINUSE[i].", XSTATE_BV[18] should be cleared after xsavec.

On the other hand, according to Intel SDM vol 1. 13.4.3: "If XCOMP_BV[i] =
1, state component i is located at a byte offset locationI from the base
address of the XSAVE area". Since at the time of xsavec, XCR0[18] is set
indicating AMX tile data component is still enabled, xcomp_bv[18] should be
set.

Complete the checks by adding the assert to xcomp_bv[18] after xsavec.

Signed-off-by: Mingwei Zhang <mizhang@google.com>
Link: https://lore.kernel.org/r/20230221163655.920289-5-mizhang@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
This commit is contained in:
Mingwei Zhang
2023-02-21 16:36:46 +00:00
committed by Sean Christopherson
parent bec357a4af
commit 48ad4222c4
1 changed files with 1 additions and 0 deletions
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1
tools/testing/selftests/kvm/x86_64/amx_test.c
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@@ -197,6 +197,7 @@ static void __attribute__((__flatten__)) guest_code(struct tile_config *amx_cfg,
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);
/* xfd=0x40000, disable amx tiledata */
wrmsr(MSR_IA32_XFD, XFEATURE_MASK_XTILEDATA);