Re: [PATCH v3 1/2] xen/events: access last_priority and last_vcpu_id together

[Julien Grall <julien@xxxxxxx>]

Hi Juergen,

On 16/10/2020 11:58, Juergen Gross wrote:
> The queue for a fifo event is depending on the vcpu_id and the
> priority of the event. When sending an event it might happen the
> event needs to change queues and the old queue needs to be kept for
> keeping the links between queue elements intact. For this purpose
> the event channel contains last_priority and last_vcpu_id values
> elements for being able to identify the old queue.
>
> In order to avoid races always access last_priority and last_vcpu_id
> with a single atomic operation avoiding any inconsistencies.
>
> Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
Reviewed-by: Julien Grall <jgrall@xxxxxxxxxx>

Cheers,

--
Julien Grall