From 878a37760e34b54a3d92569f44b0b2f073bfa46a Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Eugenio=20P=C3=A9rez?= Date: Tue, 23 Aug 2022 20:30:28 +0200 Subject: [PATCH 10/29] vhost: Delete useless read memory barrier MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit RH-Author: Laurent Vivier RH-MergeRequest: 117: vDPA SVQ Multiqueue support RH-Jira: RHELX-57 RH-Acked-by: Jason Wang RH-Acked-by: Cindy Lu RH-Acked-by: Eugenio Pérez RH-Commit: [10/25] 13fb2b317093323caf33a17f9de00a94a862ca2e (redhat/centos-stream/src/qemu-kvm) As discussed in previous series [1], this memory barrier is useless with the atomic read of used idx at vhost_svq_more_used. Deleting it. [1] https://lists.nongnu.org/archive/html/qemu-devel/2022-07/msg02616.html Signed-off-by: Eugenio Pérez Acked-by: Jason Wang Signed-off-by: Jason Wang (cherry picked from commit 9e193cec5db949e4001070442a2f7de7042ef09b) Signed-off-by: Laurent Vivier --- hw/virtio/vhost-shadow-virtqueue.c | 3 --- 1 file changed, 3 deletions(-) diff --git a/hw/virtio/vhost-shadow-virtqueue.c b/hw/virtio/vhost-shadow-virtqueue.c index b35aeef4bd..8df5296f24 100644 --- a/hw/virtio/vhost-shadow-virtqueue.c +++ b/hw/virtio/vhost-shadow-virtqueue.c @@ -509,9 +509,6 @@ size_t vhost_svq_poll(VhostShadowVirtqueue *svq) if (unlikely(g_get_monotonic_time() - start_us > 10e6)) { return 0; } - - /* Make sure we read new used_idx */ - smp_rmb(); } while (true); } -- 2.31.1