From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:54759) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eKonw-0000mS-1O for qemu-devel@nongnu.org; Fri, 01 Dec 2017 12:08:48 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eKonv-00074T-4B for qemu-devel@nongnu.org; Fri, 01 Dec 2017 12:08:47 -0500 Received: from mx1.redhat.com ([209.132.183.28]:60788) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1eKonu-00074I-Tj for qemu-devel@nongnu.org; Fri, 01 Dec 2017 12:08:47 -0500 Date: Fri, 1 Dec 2017 19:08:43 +0200 From: "Michael S. Tsirkin" Message-ID: <1512148088-28733-3-git-send-email-mst@redhat.com> References: <1512148088-28733-1-git-send-email-mst@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1512148088-28733-1-git-send-email-mst@redhat.com> Subject: [Qemu-devel] [PULL 2/7] virtio: Add queue interface to restore avail index from vring used index List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Peter Maydell , Maxime Coquelin From: Maxime Coquelin In case of backend crash, it is not possible to restore internal avail index from the backend value as vhost_get_vring_base callback fails. This patch provides a new interface to restore internal avail index from the vring used index, as done by some vhost-user backend on reconnection. Signed-off-by: Maxime Coquelin Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- include/hw/virtio/virtio.h | 1 + hw/virtio/virtio.c | 10 ++++++++++ 2 files changed, 11 insertions(+) diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h index 5abada6..098bdaa 100644 --- a/include/hw/virtio/virtio.h +++ b/include/hw/virtio/virtio.h @@ -272,6 +272,7 @@ hwaddr virtio_queue_get_avail_size(VirtIODevice *vdev, int n); hwaddr virtio_queue_get_used_size(VirtIODevice *vdev, int n); uint16_t virtio_queue_get_last_avail_idx(VirtIODevice *vdev, int n); void virtio_queue_set_last_avail_idx(VirtIODevice *vdev, int n, uint16_t idx); +void virtio_queue_restore_last_avail_idx(VirtIODevice *vdev, int n); void virtio_queue_invalidate_signalled_used(VirtIODevice *vdev, int n); void virtio_queue_update_used_idx(VirtIODevice *vdev, int n); VirtQueue *virtio_get_queue(VirtIODevice *vdev, int n); diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c index ea532dc..703e672 100644 --- a/hw/virtio/virtio.c +++ b/hw/virtio/virtio.c @@ -2310,6 +2310,16 @@ void virtio_queue_set_last_avail_idx(VirtIODevice *vdev, int n, uint16_t idx) vdev->vq[n].shadow_avail_idx = idx; } +void virtio_queue_restore_last_avail_idx(VirtIODevice *vdev, int n) +{ + rcu_read_lock(); + if (vdev->vq[n].vring.desc) { + vdev->vq[n].last_avail_idx = vring_used_idx(&vdev->vq[n]); + vdev->vq[n].shadow_avail_idx = vdev->vq[n].last_avail_idx; + } + rcu_read_unlock(); +} + void virtio_queue_update_used_idx(VirtIODevice *vdev, int n) { rcu_read_lock(); -- MST