From a311650ae6ad0c169ade2583f78aa519878ea13f Mon Sep 17 00:00:00 2001 From: "Michael S. Tsirkin" Date: Fri, 27 Oct 2017 16:11:13 +0300 Subject: virtio/ringtest: virtio_ring: fix up need_event math last kicked event index must be updated unconditionally: even if we don't need to kick, we do not want to re-check the same entry for events. Reported-by: Cornelia Huck Signed-off-by: Michael S. Tsirkin Reviewed-by: Jens Freimann --- tools/virtio/ringtest/virtio_ring_0_9.c | 24 ++++++++++++++---------- 1 file changed, 14 insertions(+), 10 deletions(-) (limited to 'tools/virtio') diff --git a/tools/virtio/ringtest/virtio_ring_0_9.c b/tools/virtio/ringtest/virtio_ring_0_9.c index bbc3043b2fb1..5fd3fbcb9e57 100644 --- a/tools/virtio/ringtest/virtio_ring_0_9.c +++ b/tools/virtio/ringtest/virtio_ring_0_9.c @@ -225,16 +225,18 @@ bool enable_call() void kick_available(void) { + bool need; + /* Flush in previous flags write */ /* Barrier C (for pairing) */ smp_mb(); - if (!vring_need_event(vring_avail_event(&ring), - guest.avail_idx, - guest.kicked_avail_idx)) - return; + need = vring_need_event(vring_avail_event(&ring), + guest.avail_idx, + guest.kicked_avail_idx); guest.kicked_avail_idx = guest.avail_idx; - kick(); + if (need) + kick(); } /* host side */ @@ -316,14 +318,16 @@ bool use_buf(unsigned *lenp, void **bufp) void call_used(void) { + bool need; + /* Flush in previous flags write */ /* Barrier D (for pairing) */ smp_mb(); - if (!vring_need_event(vring_used_event(&ring), - host.used_idx, - host.called_used_idx)) - return; + need = vring_need_event(vring_used_event(&ring), + host.used_idx, + host.called_used_idx); host.called_used_idx = host.used_idx; - call(); + if (need) + call(); } -- cgit v1.2.3