Messages in this thread Patch in this message | | | From | Juergen Gross <> | Subject | [PATCH v2 4/5] xen/events: unmask a fifo event channel only if it was masked | Date | Thu, 22 Oct 2020 11:49:06 +0200 |
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Unmasking an event channel with fifo events channels being used can require a hypercall to be made, so try to avoid that by checking whether the event channel was really masked.
Suggested-by: Jan Beulich <jbeulich@suse.com> Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Jan Beulich <jbeulich@suse.com> --- V2: - move test for already unmasked into loop (Jan Beulich) --- drivers/xen/events/events_fifo.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/drivers/xen/events/events_fifo.c b/drivers/xen/events/events_fifo.c index 243e7b6d7b96..b234f1766810 100644 --- a/drivers/xen/events/events_fifo.c +++ b/drivers/xen/events/events_fifo.c @@ -237,6 +237,9 @@ static bool clear_masked_cond(volatile event_word_t *word) w = *word; do { + if (!(w & (1 << EVTCHN_FIFO_MASKED))) + return true; + if (w & (1 << EVTCHN_FIFO_PENDING)) return false; -- 2.26.2
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