[RFC PATCH 01/13] KVM: SVM: Add warning when encounter invalid APIC ID

[Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>]

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