On 12/07/2017 09:08 AM, Tiwei Bie wrote:
On Wed, Dec 06, 2017 at 10:20:45AM +0100, Maxime Coquelin wrote:
As section 2.2 of the Virtio spec states about features
negotiation:
"During device initialization, the driver reads this and tells
the device the subset that it accepts. The only way to
renegotiate is to reset the device."
This patch implements a check to prevent illegal features change
while the device is running.
One exception is the VHOST_F_LOG_ALL feature bit, which is enabled
when live-migration is initiated. But this feature is not negotiated
with the Virtio driver, but directly with the Vhost master.
Signed-off-by: Maxime Coquelin <maxime.coque...@redhat.com>
---
lib/librte_vhost/vhost_user.c | 17 ++++++++++++++++-
1 file changed, 16 insertions(+), 1 deletion(-)
diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c
index f4c7ce462..2d86c0ca8 100644
--- a/lib/librte_vhost/vhost_user.c
+++ b/lib/librte_vhost/vhost_user.c
@@ -183,7 +183,22 @@ vhost_user_set_features(struct virtio_net *dev, uint64_t
features)
return -1;
}
- if ((dev->flags & VIRTIO_DEV_RUNNING) && dev->features != features) {
+ if (dev->features == features)
+ return 0;
+
We couldn't return directly when dev->features == features.
Otherwise, if the features provided by virtio driver is 0,
dev->vhost_hlen won't get a chance to be initialized.
Good catch.
Either we do :
if ((dev->features == features) && dev->vhost_len)
return 0;
Or we could initialize dev->vhost_len to sizeof(struct virtio_net_hdr)
at alloc time.
I prefer the former, what do you think?
Thanks,
Maxime
Best regards,
Tiwei Bie
