Re: [PATCH 05/12] evtchn/sched: reject poll requests for unusable ports

[Dario Faggioli <dfaggioli@xxxxxxxx>]

On Mon, 2020-09-28 at 12:58 +0200, Jan Beulich wrote:
> Before and after XSA-342 there has been an asymmetry in how not
> really
> usable ports get treated in do_poll(): Ones beyond a certain boundary
> (max_evtchns originally, valid_evtchns subsequently) did get refused
> with -EINVAL, while lower ones were accepted despite there
> potentially
> being no way to wake the vCPU again from its polling state. Arrange
> to
> also honor evtchn_usable() output in the decision.
> 
> Requested-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
>
Reviewed-by: Dario Faggioli <dfaggioli@xxxxxxxx>

I agree with Julien that a comment about how evtchn_port_poll() would
improve things even further.

Regards
-- 
Dario Faggioli, Ph.D
http://about.me/dario.faggioli
Virtualization Software Engineer
SUSE Labs, SUSE https://www.suse.com/
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