From fc39e561e3430694e366e228354d16abbd30ba13 Mon Sep 17 00:00:00 2001 From: Haozhong Zhang Date: Mon, 18 Sep 2017 09:56:49 +0800 Subject: KVM: VMX: do not change SN bit in vmx_update_pi_irte() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 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(-) (limited to 'arch') diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index ee7ae9e937b2..5aeddea1e9d1 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -10803,12 +10803,8 @@ 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", -- cgit v1.2.3