From patchwork Thu Aug 25 10:09:56 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Michael S. Tsirkin" X-Patchwork-Id: 111544 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [140.186.70.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id E6FDAB6F6F for ; Thu, 25 Aug 2011 20:09:19 +1000 (EST) Received: from localhost ([::1]:51094 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QwWs7-0001Kq-Tm for incoming@patchwork.ozlabs.org; Thu, 25 Aug 2011 06:09:15 -0400 Received: from eggs.gnu.org ([140.186.70.92]:49788) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QwWs2-0001KE-KQ for qemu-devel@nongnu.org; Thu, 25 Aug 2011 06:09:11 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1QwWs1-00036p-GB for qemu-devel@nongnu.org; Thu, 25 Aug 2011 06:09:10 -0400 Received: from mx1.redhat.com ([209.132.183.28]:62306) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QwWs1-00036Y-8w for qemu-devel@nongnu.org; Thu, 25 Aug 2011 06:09:09 -0400 Received: from int-mx02.intmail.prod.int.phx2.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id p7PA97Un023630 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Thu, 25 Aug 2011 06:09:07 -0400 Received: from redhat.com (vpn-200-15.tlv.redhat.com [10.35.200.15]) by int-mx02.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with SMTP id p7PA93xW021811; Thu, 25 Aug 2011 06:09:04 -0400 Date: Thu, 25 Aug 2011 13:09:56 +0300 From: "Michael S. Tsirkin" To: qemu-devel@nongnu.org, Jason Wang , akong@redhat.com, Juan Quintela , Alex Williamson Message-ID: <20110825100953.GA9945@redhat.com> MIME-Version: 1.0 Content-Disposition: inline User-Agent: Mutt/1.5.21 (2010-09-15) X-Scanned-By: MIMEDefang 2.67 on 10.5.11.12 X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 209.132.183.28 Cc: "Michael S. Tsirkin" Subject: [Qemu-devel] [PATCH] vhost-net: cleanup host notifiers at last step X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org When the vhost notifier is disabled, the userspace handler runs immediately: virtio_pci_set_host_notifier_internal might call virtio_queue_notify_vq. Since the VQ state and the tap backend state aren't recovered yet, this causes "Guest moved used index from XXX to YYY" assertions. The solution is to split out host notifier handling from vhost VQ setup and disable notifiers as our last step when we stop vhost-net. For symmetry enable them first thing on start. Signed-off-by: Michael S. Tsirkin --- hw/vhost.c | 74 +++++++++++++++++++++++++++++++++++++++++-------------- hw/vhost.h | 2 + hw/vhost_net.c | 16 ++++++++++-- 3 files changed, 70 insertions(+), 22 deletions(-) diff --git a/hw/vhost.c b/hw/vhost.c index 1886067..0870cb7 100644 --- a/hw/vhost.c +++ b/hw/vhost.c @@ -515,11 +515,6 @@ static int vhost_virtqueue_init(struct vhost_dev *dev, }; struct VirtQueue *vvq = virtio_get_queue(vdev, idx); - if (!vdev->binding->set_host_notifier) { - fprintf(stderr, "binding does not support host notifiers\n"); - return -ENOSYS; - } - vq->num = state.num = virtio_queue_get_num(vdev, idx); r = ioctl(dev->control, VHOST_SET_VRING_NUM, &state); if (r) { @@ -567,12 +562,6 @@ static int vhost_virtqueue_init(struct vhost_dev *dev, r = -errno; goto fail_alloc; } - r = vdev->binding->set_host_notifier(vdev->binding_opaque, idx, true); - if (r < 0) { - fprintf(stderr, "Error binding host notifier: %d\n", -r); - goto fail_host_notifier; - } - file.fd = event_notifier_get_fd(virtio_queue_get_host_notifier(vvq)); r = ioctl(dev->control, VHOST_SET_VRING_KICK, &file); if (r) { @@ -591,8 +580,6 @@ static int vhost_virtqueue_init(struct vhost_dev *dev, fail_call: fail_kick: - vdev->binding->set_host_notifier(vdev->binding_opaque, idx, false); -fail_host_notifier: fail_alloc: cpu_physical_memory_unmap(vq->ring, virtio_queue_get_ring_size(vdev, idx), 0, 0); @@ -618,12 +605,6 @@ static void vhost_virtqueue_cleanup(struct vhost_dev *dev, .index = idx, }; int r; - r = vdev->binding->set_host_notifier(vdev->binding_opaque, idx, false); - if (r < 0) { - fprintf(stderr, "vhost VQ %d host cleanup failed: %d\n", idx, r); - fflush(stderr); - } - assert (r >= 0); r = ioctl(dev->control, VHOST_GET_VRING_BASE, &state); if (r < 0) { fprintf(stderr, "vhost VQ %d ring restore failed: %d\n", idx, r); @@ -697,6 +678,60 @@ bool vhost_dev_query(struct vhost_dev *hdev, VirtIODevice *vdev) hdev->force; } +/* Stop processing guest IO notifications in qemu. + * Start processing them in vhost in kernel. + */ +int vhost_dev_enable_notifiers(struct vhost_dev *hdev, VirtIODevice *vdev) +{ + int i, r; + if (!vdev->binding->set_host_notifier) { + fprintf(stderr, "binding does not support host notifiers\n"); + r = -ENOSYS; + goto fail; + } + + for (i = 0; i < hdev->nvqs; ++i) { + r = vdev->binding->set_host_notifier(vdev->binding_opaque, i, true); + if (r < 0) { + fprintf(stderr, "vhost VQ %d notifier binding failed: %d\n", i, -r); + goto fail_vq; + } + } + + return 0; +fail_vq: + while (--i >= 0) { + r = vdev->binding->set_host_notifier(vdev->binding_opaque, i, false); + if (r < 0) { + fprintf(stderr, "vhost VQ %d notifier cleanup error: %d\n", i, -r); + fflush(stderr); + } + assert (r >= 0); + } +fail: + return r; +} + +/* Stop processing guest IO notifications in vhost. + * Start processing them in qemu. + * This might actually run the qemu handlers right away, + * so virtio in qemu must be completely setup when this is called. + */ +void vhost_dev_disable_notifiers(struct vhost_dev *hdev, VirtIODevice *vdev) +{ + int i, r; + + for (i = 0; i < hdev->nvqs; ++i) { + r = vdev->binding->set_host_notifier(vdev->binding_opaque, i, false); + if (r < 0) { + fprintf(stderr, "vhost VQ %d notifier cleanup failed: %d\n", i, -r); + fflush(stderr); + } + assert (r >= 0); + } +} + +/* Host notifiers must be enabled at this point. */ int vhost_dev_start(struct vhost_dev *hdev, VirtIODevice *vdev) { int i, r; @@ -762,6 +797,7 @@ fail: return r; } +/* Host notifiers must be enabled at this point. */ void vhost_dev_stop(struct vhost_dev *hdev, VirtIODevice *vdev) { int i, r; diff --git a/hw/vhost.h b/hw/vhost.h index c8c595a..c9452f0 100644 --- a/hw/vhost.h +++ b/hw/vhost.h @@ -46,5 +46,7 @@ void vhost_dev_cleanup(struct vhost_dev *hdev); bool vhost_dev_query(struct vhost_dev *hdev, VirtIODevice *vdev); int vhost_dev_start(struct vhost_dev *hdev, VirtIODevice *vdev); void vhost_dev_stop(struct vhost_dev *hdev, VirtIODevice *vdev); +int vhost_dev_enable_notifiers(struct vhost_dev *hdev, VirtIODevice *vdev); +void vhost_dev_disable_notifiers(struct vhost_dev *hdev, VirtIODevice *vdev); #endif diff --git a/hw/vhost_net.c b/hw/vhost_net.c index a559812..950a6b8 100644 --- a/hw/vhost_net.c +++ b/hw/vhost_net.c @@ -139,16 +139,22 @@ int vhost_net_start(struct vhost_net *net, { struct vhost_vring_file file = { }; int r; + + net->dev.nvqs = 2; + net->dev.vqs = net->vqs; + + r = vhost_dev_enable_notifiers(&net->dev, dev); + if (r < 0) { + goto fail_notifiers; + } if (net->dev.acked_features & (1 << VIRTIO_NET_F_MRG_RXBUF)) { tap_set_vnet_hdr_len(net->vc, sizeof(struct virtio_net_hdr_mrg_rxbuf)); } - net->dev.nvqs = 2; - net->dev.vqs = net->vqs; r = vhost_dev_start(&net->dev, dev); if (r < 0) { - return r; + goto fail_start; } net->vc->info->poll(net->vc, false); @@ -173,6 +179,9 @@ fail: if (net->dev.acked_features & (1 << VIRTIO_NET_F_MRG_RXBUF)) { tap_set_vnet_hdr_len(net->vc, sizeof(struct virtio_net_hdr)); } +fail_start: + vhost_dev_disable_notifiers(&net->dev, dev); +fail_notifiers: return r; } @@ -190,6 +199,7 @@ void vhost_net_stop(struct vhost_net *net, if (net->dev.acked_features & (1 << VIRTIO_NET_F_MRG_RXBUF)) { tap_set_vnet_hdr_len(net->vc, sizeof(struct virtio_net_hdr)); } + vhost_dev_disable_notifiers(&net->dev, dev); } void vhost_net_cleanup(struct vhost_net *net)