From: "Suthikulpanit, Suravee" <Suravee.Suthikulpanit@amd.com>
Date: Fri, 3 May 2019 06:38:53 -0700
Subject: kvm: svm/avic: Do not send AVIC doorbell to self
Git-commit: 0532dd52dfec0cf774188d3e692d50c197bc4210
References: bsc#1140133
Patch-mainline: v5.3-rc1
AVIC doorbell is used to notify a running vCPU that interrupts
has been injected into the vCPU AVIC backing page. Current logic
checks only if a VCPU is running before sending a doorbell.
However, the doorbell is not necessary if the destination
CPU is itself.
Add logic to check currently running CPU before sending doorbell.
Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Reviewed-by: Alexander Graf <graf@amazon.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Acked-by: Joerg Roedel <jroedel@suse.de>
---
arch/x86/kvm/svm.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index a7ea34bed3fe..c56f40d430e5 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -5163,10 +5163,13 @@ static void svm_deliver_avic_intr(struct kvm_vcpu *vcpu, int vec)
kvm_lapic_set_irr(vec, vcpu->arch.apic);
smp_mb__after_atomic();
- if (avic_vcpu_is_running(vcpu))
- wrmsrl(SVM_AVIC_DOORBELL,
- kvm_cpu_get_apicid(vcpu->cpu));
- else
+ if (avic_vcpu_is_running(vcpu)) {
+ int cpuid = vcpu->cpu;
+
+ if (cpuid != get_cpu())
+ wrmsrl(SVM_AVIC_DOORBELL, kvm_cpu_get_apicid(cpuid));
+ put_cpu();
+ } else
kvm_vcpu_wake_up(vcpu);
}