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authorHaozhong Zhang <haozhong.zhang@intel.com>2017-09-18 09:56:49 +0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-10-05 09:47:36 +0200
commit18d3d3bee06e9f0823c0df4f1e5581d2a7947f3a (patch)
parent7c6bcb52072cb117e7792dca856944f05182bd19 (diff)
KVM: VMX: do not change SN bit in vmx_update_pi_irte()
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 <haozhong.zhang@intel.com> Reported-by: "Ramamurthy, Venkatesh" <venkatesh.ramamurthy@intel.com> Reported-by: Dan Williams <dan.j.williams@intel.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Fixes: 28b835d60fcc ("KVM: Update Posted-Interrupts Descriptor when vCPU is preempted") Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1 files changed, 1 insertions, 5 deletions
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 1b8b1a1bf7e9..ce8c2aa46ec2 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -11604,12 +11604,8 @@ 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",