Checking the mode is unnecessary, and is done without a memory barrier separating the LAPIC write from the vcpu->mode read; in addition, kvm_vcpu_wake_up is already doing a check for waiters on the wait queue that has the same effect.
In practice it's safe because spin_lock has full-barrier semantics on x86, but don't be too clever. Signed-off-by: Paolo Bonzini <[email protected]> --- arch/x86/kvm/svm.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index 01e6e8fab5d6..712406f725a2 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -1034,15 +1034,12 @@ static int avic_ga_log_notifier(u32 ga_tag) } spin_unlock_irqrestore(&svm_vm_data_hash_lock, flags); - if (!vcpu) - return 0; - /* Note: * At this point, the IOMMU should have already set the pending * bit in the vAPIC backing page. So, we just need to schedule * in the vcpu. */ - if (vcpu->mode == OUTSIDE_GUEST_MODE) + if (vcpu) kvm_vcpu_wake_up(vcpu); return 0; -- 1.8.3.1
