qemu-kvm/kvm-vhost-Delete-useless-re...

48 lines
1.7 KiB
Diff

From 878a37760e34b54a3d92569f44b0b2f073bfa46a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Eugenio=20P=C3=A9rez?= <eperezma@redhat.com>
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 <lvivier@redhat.com>
RH-MergeRequest: 117: vDPA SVQ Multiqueue support
RH-Jira: RHELX-57
RH-Acked-by: Jason Wang <jasowang@redhat.com>
RH-Acked-by: Cindy Lu <lulu@redhat.com>
RH-Acked-by: Eugenio Pérez <eperezma@redhat.com>
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 <eperezma@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
(cherry picked from commit 9e193cec5db949e4001070442a2f7de7042ef09b)
Signed-off-by: Laurent Vivier <lvivier@redhat.com>
---
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