linux-kernel - [PATCH v2 5/7] KVM: selftests: Fix the checks to XFD

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Message-ID: <20230214184606.510551-6-mizhang@google.com>
Date:   Tue, 14 Feb 2023 18:46:04 +0000
From:   Mingwei Zhang <mizhang@...gle.com>
To:     Sean Christopherson <seanjc@...gle.com>,
        Paolo Bonzini <pbonzini@...hat.com>
Cc:     kvm@...r.kernel.org, linux-kselftest@...r.kernel.org,
        linux-kernel@...r.kernel.org, Mingwei Zhang <mizhang@...gle.com>,
        Jim Mattson <jmattson@...gle.com>,
        Venkatesh Srinivas <venkateshs@...gle.com>,
        Aaron Lewis <aaronlewis@...gle.com>,
        "Chang S. Bae" <chang.seok.bae@...el.com>
Subject: [PATCH v2 5/7] KVM: selftests: Fix the checks to XFD_ERR using and operation

Fix the checks to XFD_ERR using logical AND operation because XFD_ERR might
contain more information in the future. According Intel SDM Vol 1. 13.14:

"Specifically, the MSR is loaded with the logical AND of the IA32_XFD MSR
and the bitmap corresponding to the state component(s) required by the
faulting instruction."

So fix the check by using AND instead of '=='.

Signed-off-by: Mingwei Zhang <mizhang@...gle.com>
---
 tools/testing/selftests/kvm/x86_64/amx_test.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/kvm/x86_64/amx_test.c b/tools/testing/selftests/kvm/x86_64/amx_test.c
index 44c907215343..bd8bd9936f8e 100644
--- a/tools/testing/selftests/kvm/x86_64/amx_test.c
+++ b/tools/testing/selftests/kvm/x86_64/amx_test.c
@@ -216,10 +216,10 @@ void guest_nm_handler(struct ex_regs *regs)
 	/* Check if #NM is triggered by XFEATURE_MASK_XTILEDATA */
 	GUEST_SYNC(7);
 	GUEST_ASSERT((get_cr0() & X86_CR0_TS) == 0);
-	GUEST_ASSERT(rdmsr(MSR_IA32_XFD_ERR) == XFEATURE_MASK_XTILEDATA);
+	GUEST_ASSERT(rdmsr(MSR_IA32_XFD_ERR) & XFEATURE_MASK_XTILEDATA);
 	GUEST_ASSERT(rdmsr(MSR_IA32_XFD) & XFEATURE_MASK_XTILEDATA);
 	GUEST_SYNC(8);
-	GUEST_ASSERT(rdmsr(MSR_IA32_XFD_ERR) == XFEATURE_MASK_XTILEDATA);
+	GUEST_ASSERT(rdmsr(MSR_IA32_XFD_ERR) & XFEATURE_MASK_XTILEDATA);
 	GUEST_ASSERT(rdmsr(MSR_IA32_XFD) & XFEATURE_MASK_XTILEDATA);
 	/* Clear xfd_err */
 	wrmsr(MSR_IA32_XFD_ERR, 0);
-- 
2.39.1.581.gbfd45094c4-goog