[PATCH v2 2/7] KVM: selftests: x86: Fix an error in comment of amx_test

[Mingwei Zhang]

After the execution of __tilerelease(), AMX component will be in INIT
state. Therefore, execution of XSAVEC saving the AMX state into memory will
cause the xstate_bv[18] cleared in xheader. However, the xcomp_bv[18] will
remain set. Fix the error in comment. Also, update xsavec() to XSAVEC
because xcomp_bv[18] is set due to the instruction, not the function.
Finally, use XTILEDATA instead 'bit 18' in comments.

Cc: Jim Mattson <jmattson@xxxxxxxxxx>
Cc: Venkatesh Srinivas <venkateshs@xxxxxxxxxx>
Cc: Aaron Lewis <aaronlewis@xxxxxxxxxx>
Signed-off-by: Mingwei Zhang <mizhang@xxxxxxxxxx>
---
 tools/testing/selftests/kvm/x86_64/amx_test.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/kvm/x86_64/amx_test.c b/tools/testing/selftests/kvm/x86_64/amx_test.c
index d506821a5a26..aac727ff7cf8 100644
--- a/tools/testing/selftests/kvm/x86_64/amx_test.c
+++ b/tools/testing/selftests/kvm/x86_64/amx_test.c
@@ -190,7 +190,10 @@ static void __attribute__((__flatten__)) guest_code(struct tile_config *amx_cfg,
 	GUEST_SYNC(4);
 	__tilerelease();
 	GUEST_SYNC(5);
-	/* bit 18 not in the XCOMP_BV after xsavec() */
+	/*
+	 * After XSAVEC, XTILEDATA is cleared in the xstate_bv but is set in
+	 * the xcomp_bv.
+	 */
 	xstate->header.xstate_bv = XFEATURE_MASK_XTILEDATA;
 	__xsavec(xstate, XFEATURE_MASK_XTILEDATA);
 	GUEST_ASSERT(!(xstate->header.xstate_bv & XFEATURE_MASK_XTILEDATA));
-- 
2.39.1.581.gbfd45094c4-goog