On 12/04/2017 03:17 PM, Ladi Prosek wrote:
On Mon, Dec 4, 2017 at 3:08 PM, Maxime Coquelin <maxime.coque...@redhat.com> 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..f51055ab2 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; + + if (dev->flags & VIRTIO_DEV_RUNNING) { + /* + * Error out if master tries to change features while device is + * in running state. The exception being VHOST_F_LOG_ALL, which + * is enabled when the live-migration starts. + */ + if ((dev->features ^ features) & ~(1ULL >> VHOST_F_LOG_ALL)) {The 1 should be shifted to the left: 1ULL << VHOST_F_LOG_ALL
Oh right, of course. Thanks for spotting this. Maxime
