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From:   Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
To:     <linux-kernel@vger.kernel.org>, <kvm@vger.kernel.org>
CC:     <pbonzini@redhat.com>, <seanjc@google.com>, <joro@8bytes.org>,
        <jon.grimm@amd.com>, <wei.huang2@amd.com>, <terry.bowman@amd.com>,
        "Suravee Suthikulpanit" <suravee.suthikulpanit@amd.com>
Subject: [RFC PATCH 01/13] KVM: SVM: Add warning when encounter invalid APIC ID
Date:   Sun, 20 Feb 2022 20:19:10 -0600
Message-ID: <20220221021922.733373-2-suravee.suthikulpanit@amd.com>
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Current logic checks if avic_get_physical_id_entry() fails to
get the entry, and return error. This could silently cause
AVIC to fail to operate.  Therefore, add WARN_ON to help
report this error.

Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
---
 arch/x86/kvm/svm/avic.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/svm/avic.c b/arch/x86/kvm/svm/avic.c
index f07956f15d3b..472445aaaf42 100644
--- a/arch/x86/kvm/svm/avic.c
+++ b/arch/x86/kvm/svm/avic.c
@@ -447,8 +447,10 @@ static int avic_handle_apic_id_update(struct kvm_vcpu *vcpu)
 
 	old = avic_get_physical_id_entry(vcpu, vcpu->vcpu_id);
 	new = avic_get_physical_id_entry(vcpu, id);
-	if (!new || !old)
+	if (!new || !old) {
+		WARN_ON(1);
 		return 1;
+	}
 
 	/* We need to move physical_id_entry to new offset */
 	*new = *old;
-- 
2.25.1