From 14c81b2191fffb61cd6d2a7a839d34ec2d5e09a1 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Eugenio=20P=C3=A9rez?= Date: Thu, 4 Nov 2021 09:56:25 +0100 Subject: [PATCH] vhost: Fix last vq queue index of devices with no cvq MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The -1 assumes that cvq device model is accounted in data_queue_pairs, if cvq does not exists, but it's actually the opposite: Devices with !cvq are ok but devices with cvq does not add the last queue to data_queue_pairs. This is not a problem to vhost-net, but it is to vhost-vdpa: * Devices with cvq gets initialized at last data vq device model, not at cvq one. * Devices with !cvq never gets initialized, since last_index is the first queue of the last device model. Because of that, the right change in last_index is to actually add the cvq, not to remove the missing one. This is not a problem to vhost-net, but it is to vhost-vdpa, which device model trust to reach the last index to finish starting the device. Also, as the previous commit, rename it to index_end. Tested with vp_vdpa with host's vhost=on and vhost=off, with ctrl_vq=on and ctrl_vq=off. Fixes: 049eb15b5fc9 ("vhost: record the last virtqueue index for the virtio device") Reviewed-by: Juan Quintela Signed-off-by: Eugenio Pérez Message-Id: <20211104085625.2054959-3-eperezma@redhat.com> Acked-by: Jason Wang Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- hw/net/vhost_net.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/hw/net/vhost_net.c b/hw/net/vhost_net.c index 29f2c4212f..30379d2ca4 100644 --- a/hw/net/vhost_net.c +++ b/hw/net/vhost_net.c @@ -326,11 +326,11 @@ int vhost_net_start(VirtIODevice *dev, NetClientState *ncs, VirtIONet *n = VIRTIO_NET(dev); int nvhosts = data_queue_pairs + cvq; struct vhost_net *net; - int r, e, i, last_index = data_queue_pairs * 2; + int r, e, i, index_end = data_queue_pairs * 2; NetClientState *peer; - if (!cvq) { - last_index -= 1; + if (cvq) { + index_end += 1; } if (!k->set_guest_notifiers) { @@ -347,7 +347,7 @@ int vhost_net_start(VirtIODevice *dev, NetClientState *ncs, } net = get_vhost_net(peer); - vhost_net_set_vq_index(net, i * 2, last_index); + vhost_net_set_vq_index(net, i * 2, index_end); /* Suppress the masking guest notifiers on vhost user * because vhost user doesn't interrupt masking/unmasking