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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 <cohuck@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Jens Freimann <jfreimann@redhat.com>
hifive-unleashed-5.1
Michael S. Tsirkin 2017-10-27 16:11:13 +03:00
parent f229a55c31
commit a311650ae6
1 changed files with 14 additions and 10 deletions
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24
tools/virtio/ringtest/virtio_ring_0_9.c
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@ -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();
}