From: Paolo Bonzini Date: Tue, 10 Oct 2017 10:51:56 +0000 (+0200) Subject: KVM: SVM: unconditionally wake up VCPU on IOMMU interrupt X-Git-Tag: v4.19~2163^2~16 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=1cf53587c03025885af359da3bd0be091aa34b53;p=platform%2Fkernel%2Flinux-rpi.git KVM: SVM: unconditionally wake up VCPU on IOMMU interrupt 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. Reviewed-by: Radim Krčmář Signed-off-by: Paolo Bonzini --- diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index 0e68f0b..3e4337e 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;