Hi Stefan,
On 01/31/2018 06:46 PM, Stefan Hajnoczi wrote:
Commit e29109323595beb3884da58126ebb3b878cb66f5 ("vhost: destroy unused
virtqueues when multiqueue not negotiated") broke vhost-scsi by removing
virtqueues when the virtio-net-specific VIRTIO_NET_F_MQ feature bit is
missing.
The vhost_user.c code shouldn't assume all devices are vhost net device
backends. Use the new VIRTIO_DEV_BUILTIN_VIRTIO_NET flag to check
whether virtio_net.c is being used.
This fixes examples/vhost_scsi.
Cc: Maxime Coquelin <maxime.coque...@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefa...@redhat.com>
---
lib/librte_vhost/vhost_user.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c
index 1dd1a61b6..65ee33919 100644
--- a/lib/librte_vhost/vhost_user.c
+++ b/lib/librte_vhost/vhost_user.c
@@ -187,7 +187,8 @@ vhost_user_set_features(struct virtio_net *dev, uint64_t
features)
(dev->features & (1 << VIRTIO_NET_F_MRG_RXBUF)) ? "on" : "off",
(dev->features & (1ULL << VIRTIO_F_VERSION_1)) ? "on" : "off");
- if (!(dev->features & (1ULL << VIRTIO_NET_F_MQ))) {
+ if ((dev->flags & VIRTIO_DEV_BUILTIN_VIRTIO_NET) &&
+ !(dev->features & (1ULL << VIRTIO_NET_F_MQ))) {
If we had an external net backend using the library, we would also need
to remove extra queues if it advertised VIRTIO_NET_F_MQ, but the feature
isn't negotiated.
In this case, the fix I suggested yesterday would work:
if ((vhost_features & (1ULL << VIRTIO_NET_F_MQ)) &&
!(dev->features & (1ULL << VIRTIO_NET_F_MQ)) {
...
}
For any backend that does not advertise the feature, no queues will be
destroyed.
Thanks,
Maxime
/*
* Remove all but first queue pair if MQ hasn't been
* negotiated. This is safe because the device is not
