Re: [patch 2/2] x86/kvm: Sanitize kvm_async_pf_task_wait()

From: Thomas Gleixner
Date: Sat Mar 07 2020 - 15:09:09 EST


Andy Lutomirski <luto@xxxxxxxxxx> writes:
> On Sat, Mar 7, 2020 at 7:52 AM Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote:
>> WHAT? That's fundamentally broken. Can you point me to the code in
>> question?
>
> I think Paolo said so in a different thread, but I can't Let me see if
> I can find it:
>
> kvm_pv_enable_async_pf()
> kvm_clear_async_pf_completion_queue()
>
> but that doesn't actually seem to send #PF. So maybe I'm wrong.
>
> I will admit that, even after reading the host code a few times, I'm
> also not convinced that wakeups don't get swallowed on occasion if
> they would have been delivered at times when it's illegal.

I gave up trying to decode it. I wait for the kvm wizards to answer all
our nasty questions :)

Thanks,

tglx