From 0c4e39ca67008b983d71fe23ee04c6a33ce4b5f4 Mon Sep 17 00:00:00 2001 From: Haozhong Zhang Date: Mon, 18 Sep 2017 09:56:49 +0800 Subject: [PATCH] KVM: VMX: do not change SN bit in vmx_update_pi_irte() MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit commit dc91f2eb1a4021eb6705c15e474942f84ab9b211 upstream. In kvm_vcpu_trigger_posted_interrupt() and pi_pre_block(), KVM assumes that PI notification events should not be suppressed when the target vCPU is not blocked. vmx_update_pi_irte() sets the SN field before changing an interrupt from posting to remapping, but it does not check the vCPU mode. Therefore, the change of SN field may break above the assumption. Besides, I don't see reasons to suppress notification events here, so remove the changes of SN field to avoid race condition. Signed-off-by: Haozhong Zhang Reported-by: "Ramamurthy, Venkatesh" Reported-by: Dan Williams Reviewed-by: Paolo Bonzini Fixes: 28b835d60fcc ("KVM: Update Posted-Interrupts Descriptor when vCPU is preempted") Signed-off-by: Radim Krčmář Signed-off-by: Greg Kroah-Hartman --- arch/x86/kvm/vmx.c | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-) diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index a29f545..81a3ab2 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -11215,12 +11215,8 @@ static int vmx_update_pi_irte(struct kvm *kvm, unsigned int host_irq, if (set) ret = irq_set_vcpu_affinity(host_irq, &vcpu_info); - else { - /* suppress notification event before unposting */ - pi_set_sn(vcpu_to_pi_desc(vcpu)); + else ret = irq_set_vcpu_affinity(host_irq, NULL); - pi_clear_sn(vcpu_to_pi_desc(vcpu)); - } if (ret < 0) { printk(KERN_INFO "%s: failed to update PI IRTE\n", -- 2.7.4