From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:53089) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZoCZT-0002RZ-5j for qemu-devel@nongnu.org; Mon, 19 Oct 2015 11:42:00 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZoCZP-0003Yv-7W for qemu-devel@nongnu.org; Mon, 19 Oct 2015 11:41:59 -0400 Received: from mx1.redhat.com ([209.132.183.28]:57395) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZoCZP-0003Yq-1e for qemu-devel@nongnu.org; Mon, 19 Oct 2015 11:41:55 -0400 Date: Mon, 19 Oct 2015 18:41:50 +0300 From: "Michael S. Tsirkin" Message-ID: <20151019183948-mutt-send-email-mst@redhat.com> References: <1445259567-28516-1-git-send-email-thibaut.collet@6wind.com> <1445259567-28516-2-git-send-email-thibaut.collet@6wind.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1445259567-28516-2-git-send-email-thibaut.collet@6wind.com> Subject: Re: [Qemu-devel] [PATCH 1/1] vhost: set the correct queue index in case of migration with multiqueue List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Thibaut Collet Cc: pbonzini@redhat.com, jasowang@redhat.com, marcandre.lureau@gmail.com, qemu-devel@nongnu.org, haifeng.lin@huawei.com On Mon, Oct 19, 2015 at 02:59:27PM +0200, Thibaut Collet wrote: > When a live migration is started the log address to mark dirty pages is provided > to the vhost backend through the vhost_dev_set_log function. > This function is called for each queue pairs but the queue index is wrongly set: > always set to the first queue pair. Then vhost backend lost descriptor addresses > of the queue pairs greater than 1 and behaviour of the vhost backend is > unpredictable. > > The queue index is computed by taking account of the vq_index (to retrieve the > queue pair index) and calling the vhost_get_vq_index method of the backend. > > Signed-off-by: Thibaut Collet This needs some thought to make sure we don't break the kernel vhost. I queued this temporarily to enable your testing but I think it would be preferable to make vhost_virtqueue_set_addr for vhost_user call vhost_get_vq_index internally. > --- > hw/virtio/vhost.c | 8 +++++--- > 1 file changed, 5 insertions(+), 3 deletions(-) > > diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c > index feeaaa4..de29968 100644 > --- a/hw/virtio/vhost.c > +++ b/hw/virtio/vhost.c > @@ -656,13 +656,14 @@ static int vhost_dev_set_features(struct vhost_dev *dev, bool enable_log) > > static int vhost_dev_set_log(struct vhost_dev *dev, bool enable_log) > { > - int r, t, i; > + int r, t, i, idx; > r = vhost_dev_set_features(dev, enable_log); > if (r < 0) { > goto err_features; > } > for (i = 0; i < dev->nvqs; ++i) { > - r = vhost_virtqueue_set_addr(dev, dev->vqs + i, i, > + idx = dev->vhost_ops->vhost_get_vq_index(dev, dev->vq_index + i); > + r = vhost_virtqueue_set_addr(dev, dev->vqs + i, idx, > enable_log); > if (r < 0) { > goto err_vq; > @@ -671,7 +672,8 @@ static int vhost_dev_set_log(struct vhost_dev *dev, bool enable_log) > return 0; > err_vq: > for (; i >= 0; --i) { > - t = vhost_virtqueue_set_addr(dev, dev->vqs + i, i, > + idx = dev->vhost_ops->vhost_get_vq_index(dev, dev->vq_index + i); > + t = vhost_virtqueue_set_addr(dev, dev->vqs + i, idx, > dev->log_enabled); > assert(t >= 0); > } > -- > 2.1.4