On Thu, Dec 19, 2019 at 04:28:15PM +0100, Frederic Weisbecker wrote:
> Hi,
>
> While checking the x86 async page fault code, I can't
> find anything that prevents KVM_PV_REASON_PAGE_READY to be injected
> while the guest has interrupts disabled. If that page fault happens
> to trap in an interrupt disabled section, there may be a deadlock due to the
> call to wake_up_process() which locks the rq->lock (among others).
>
> Given how long that code is there, I guess such an issue would
> have been reported for a while already. But I just would like to
> be sure we are checking that.
>
> Can someone enlighten me?
The check is triggered from the caller of kvm_async_page_present().
kvm_check_async_pf_completion()
|
|-> kvm_arch_can_inject_async_page_present()
|
|-> kvm_can_do_async_pf()
|
|-> kvm_x86_ops->interrupt_allowed()
