From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:49728) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eMfCc-0000tU-2q for qemu-devel@nongnu.org; Wed, 06 Dec 2017 14:17:56 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eMfCZ-0000u2-Mk for qemu-devel@nongnu.org; Wed, 06 Dec 2017 14:17:54 -0500 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:50390) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1eMfCZ-0000sx-E6 for qemu-devel@nongnu.org; Wed, 06 Dec 2017 14:17:51 -0500 Received: from pps.filterd (m0098393.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.21/8.16.0.21) with SMTP id vB6JEb0h013906 for ; Wed, 6 Dec 2017 14:17:50 -0500 Received: from e36.co.us.ibm.com (e36.co.us.ibm.com [32.97.110.154]) by mx0a-001b2d01.pphosted.com with ESMTP id 2epm4274x4-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Wed, 06 Dec 2017 14:17:50 -0500 Received: from localhost by e36.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 6 Dec 2017 12:17:48 -0700 From: Michael Roth Date: Wed, 6 Dec 2017 13:16:34 -0600 In-Reply-To: <20171206191648.18208-1-mdroth@linux.vnet.ibm.com> References: <20171206191648.18208-1-mdroth@linux.vnet.ibm.com> Message-Id: <20171206191648.18208-42-mdroth@linux.vnet.ibm.com> Subject: [Qemu-devel] [PATCH 41/55] 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: qemu-stable@nongnu.org, Maxime Coquelin , "Michael S . Tsirkin" 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 (cherry picked from commit 2d4ba6cc741df15df6fbb4feaa706a02e103083a) Signed-off-by: Michael Roth --- hw/virtio/virtio.c | 10 ++++++++++ include/hw/virtio/virtio.h | 1 + 2 files changed, 11 insertions(+) diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c index 464947f76d..15cf6021a0 100644 --- a/hw/virtio/virtio.c +++ b/hw/virtio/virtio.c @@ -2311,6 +2311,16 @@ 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(); diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h index 80c45c321e..3d5c84e829 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); -- 2.11.0