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@xxxxxxxxx>
Reported-by: "Ramamurthy, Venkatesh" <venkatesh.ramamurthy@xxxxxxxxx>
Reported-by: Dan Williams <dan.j.williams@xxxxxxxxx>
---
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 a406afbb6d21..fb611847ea99 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -11911,12 +11911,8 @@ 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",
--
2.11.0
