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authorjakllsch <jakllsch@NetBSD.org>2023-01-03 19:33:31 +0000
committerjakllsch <jakllsch@NetBSD.org>2023-01-03 19:33:31 +0000
commitcb6d5de685fa6737a6a2fca3d37e9f589aa12dfe (patch)
treeb2ae64d2b94fe3fdfc2fa53a25b0557db572e306 /sys/dev
parentd8e0b302659408b493dd67c46deaa38c02f398b9 (diff)
Subtly adjust criteria for notification of Virtio devices in
VIRTIO_F_RING_EVENT_IDX mode. This fixes stalls in the vioif(4) transmit path that would happen sooner or later, depending on interface transmit utilization, and were particularly noticable with a NetBSD guest transmitting to its x86 KVM host at multi-gigabit speeds.
Diffstat (limited to 'sys/dev')
-rw-r--r--sys/dev/pci/virtio.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/sys/dev/pci/virtio.c b/sys/dev/pci/virtio.c
index 38f7ecb2a66..39301d61cc2 100644
--- a/sys/dev/pci/virtio.c
+++ b/sys/dev/pci/virtio.c
@@ -1,4 +1,4 @@
-/* $NetBSD: virtio.c,v 1.64 2022/12/30 21:38:13 jakllsch Exp $ */
+/* $NetBSD: virtio.c,v 1.65 2023/01/03 19:33:31 jakllsch Exp $ */
/*
* Copyright (c) 2020 The NetBSD Foundation, Inc.
@@ -28,7 +28,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: virtio.c,v 1.64 2022/12/30 21:38:13 jakllsch Exp $");
+__KERNEL_RCSID(0, "$NetBSD: virtio.c,v 1.65 2023/01/03 19:33:31 jakllsch Exp $");
#include <sys/param.h>
#include <sys/systm.h>
@@ -1148,7 +1148,7 @@ notify:
uint16_t o, n, t;
uint16_t flags;
- o = virtio_rw16(sc, vq->vq_avail->idx);
+ o = virtio_rw16(sc, vq->vq_avail->idx) - 1;
n = vq->vq_avail_idx;
/*