From:   Lai Jiangshan <jiangshanlai@gmail.com>
To:     linux-kernel@vger.kernel.org
Cc:     Paolo Bonzini <pbonzini@redhat.com>,
        Sean Christopherson <seanjc@google.com>,
        Lai Jiangshan <jiangshan.ljs@antgroup.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        Dave Hansen <dave.hansen@linux.intel.com>, x86@kernel.org,
        "H. Peter Anvin" <hpa@zytor.com>, kvm@vger.kernel.org
Subject: [PATCH V3 03/14] kvm: x86/mmu: Check mmu->sync_page pointer in kvm_sync_page_check()
Date:   Thu, 16 Feb 2023 23:41:09 +0800
Message-Id: <20230216154115.710033-4-jiangshanlai@gmail.com>
In-Reply-To: <20230216154115.710033-1-jiangshanlai@gmail.com>
References: <20230216154115.710033-1-jiangshanlai@gmail.com>
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From: Lai Jiangshan <jiangshan.ljs@antgroup.com>

Check the pointer before calling it to catch any possible mistake.

Signed-off-by: Lai Jiangshan <jiangshan.ljs@antgroup.com>
---
 arch/x86/kvm/mmu/mmu.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index ee2837ea18d4..69ab0d1bb0ec 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -1940,7 +1940,7 @@ static bool kvm_sync_page_check(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
 	 * differs then the memslot lookup (SMM vs. non-SMM) will be bogus, the
 	 * reserved bits checks will be wrong, etc...
 	 */
-	if (WARN_ON_ONCE(sp->role.direct ||
+	if (WARN_ON_ONCE(sp->role.direct || !vcpu->arch.mmu->sync_page ||
 			 (sp->role.word ^ root_role.word) & ~sync_role_ign.word))
 		return false;
 
-- 
2.19.1.6.gb485710b