On Wed, Sep 27, 2017 at 11:22:39AM +0800, Haozhong Zhang wrote:
> 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@xxxxxxxxx>
> Reported-by: "Ramamurthy, Venkatesh" <venkatesh.ramamurthy@xxxxxxxxx>
> Reported-by: Dan Williams <dan.j.williams@xxxxxxxxx>
> Reviewed-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
> Fixes: 28b835d60fcc ("KVM: Update Posted-Interrupts Descriptor when vCPU is preempted")
Also applied to 4.9 and 4.4 stable trees, as that's what this patch
fixes.
thanks,
greg k-h