From: Juergen Gross <jgross@suse.com>
To: xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org
Cc: Juergen Gross <jgross@suse.com>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
Stefano Stabellini <sstabellini@kernel.org>,
Jan Beulich <jbeulich@suse.com>
Subject: [PATCH 4/5] xen/events: unmask a fifo event channel only if it was masked
Date: Thu, 22 Oct 2020 09:42:13 +0200 [thread overview]
Message-ID: <20201022074214.21693-5-jgross@suse.com> (raw)
In-Reply-To: <20201022074214.21693-1-jgross@suse.com>
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>
---
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..f60c5a9ec833 100644
--- a/drivers/xen/events/events_fifo.c
+++ b/drivers/xen/events/events_fifo.c
@@ -236,6 +236,9 @@ static bool clear_masked_cond(volatile event_word_t *word)
w = *word;
+ if (!(w & (1 << EVTCHN_FIFO_MASKED)))
+ return true;
+
do {
if (w & (1 << EVTCHN_FIFO_PENDING))
return false;
--
2.26.2
next prev parent reply other threads:[~2020-10-22 7:42 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-22 7:42 [PATCH 0/5] xen: event handling cleanup Juergen Gross
2020-10-22 7:42 ` [PATCH 1/5] xen: remove no longer used functions Juergen Gross
2020-10-22 7:42 ` [PATCH 2/5] xen/events: make struct irq_info private to events_base.c Juergen Gross
2020-10-22 7:42 ` [PATCH 3/5] xen/events: only register debug interrupt for 2-level events Juergen Gross
2020-10-22 7:54 ` Jan Beulich
2020-10-22 8:28 ` Jürgen Groß
2020-10-22 7:42 ` Juergen Gross [this message]
2020-10-22 7:55 ` [PATCH 4/5] xen/events: unmask a fifo event channel only if it was masked Jan Beulich
2020-10-22 8:28 ` Jürgen Groß
2020-10-22 7:42 ` [PATCH 5/5] Documentation: add xen.fifo_events kernel parameter description Juergen Gross
2020-10-22 8:01 ` [PATCH 0/5] xen: event handling cleanup Jan Beulich
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