On 03.05.19 15:38, Suthikulpanit, Suravee wrote:
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@xxxxxxx>
Reviewed-by: Alexander Graf <graf@xxxxxxxxxx>
---
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 122788f..4bbf6fc 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -5283,10 +5283,13 @@ 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())
Tiny nitpick: What would keep you from checking vcpu->cpu directly here?
Alex
+ wrmsrl(SVM_AVIC_DOORBELL, kvm_cpu_get_apicid(cpuid));
+ put_cpu();
+ } else
kvm_vcpu_wake_up(vcpu);
}
