From patchwork Wed Sep 7 15:20:49 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ladi Prosek X-Patchwork-Id: 9319507 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 0555E60752 for ; Wed, 7 Sep 2016 15:21:36 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id F3E89293B7 for ; Wed, 7 Sep 2016 15:21:35 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id E89FC293D9; Wed, 7 Sep 2016 15:21:35 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id E1DD4293DA for ; Wed, 7 Sep 2016 15:21:33 +0000 (UTC) Received: from localhost ([::1]:41524 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bhefN-0000u1-1W for patchwork-qemu-devel@patchwork.kernel.org; Wed, 07 Sep 2016 11:21:33 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:44254) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bheev-0000sD-9a for qemu-devel@nongnu.org; Wed, 07 Sep 2016 11:21:06 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bheet-0003Qx-4V for qemu-devel@nongnu.org; Wed, 07 Sep 2016 11:21:04 -0400 Received: from mx1.redhat.com ([209.132.183.28]:57146) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bhees-0003Qp-VA for qemu-devel@nongnu.org; Wed, 07 Sep 2016 11:21:03 -0400 Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 5AEF47F74D; Wed, 7 Sep 2016 15:21:02 +0000 (UTC) Received: from dhcp-1-107.brq.redhat.com (dhcp-1-127.brq.redhat.com [10.34.1.127]) by int-mx09.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id u87FKt01003232; Wed, 7 Sep 2016 11:21:01 -0400 From: Ladi Prosek To: qemu-devel@nongnu.org Date: Wed, 7 Sep 2016 17:20:49 +0200 Message-Id: <1473261649-31465-4-git-send-email-lprosek@redhat.com> In-Reply-To: <1473261649-31465-1-git-send-email-lprosek@redhat.com> References: <1473261649-31465-1-git-send-email-lprosek@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.22 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.27]); Wed, 07 Sep 2016 15:21:02 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH 3/3] virtio-balloon: fix stats vq migration X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: lprosek@redhat.com, rkagan@virtuozzo.com, stefanha@redhat.com, mst@redhat.com Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Virus-Scanned: ClamAV using ClamSMTP The statistics virtqueue is not migrated properly because virtio-balloon does not include s->stats_vq_elem in the migration stream. After migration the statistics virtqueue hangs because the host never completes the last element (s->stats_vq_elem is NULL on the destination QEMU). Therefore the guest never submits new elements and the virtqueue is hung. Instead of changing the migration stream format in an incompatible way, detect the migration case and rewind the virtqueue so the last element can be completed. Cc: Michael S. Tsirkin Cc: Roman Kagan Cc: Stefan Hajnoczi Suggested-by: Roman Kagan Signed-off-by: Ladi Prosek Reviewed-by: Stefan Hajnoczi Reviewed-by: Roman Kagan --- hw/virtio/virtio-balloon.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c index ad4189a..49a2f4a 100644 --- a/hw/virtio/virtio-balloon.c +++ b/hw/virtio/virtio-balloon.c @@ -469,6 +469,18 @@ static void virtio_balloon_device_reset(VirtIODevice *vdev) } } +static void virtio_balloon_set_status(VirtIODevice *vdev, uint8_t status) +{ + VirtIOBalloon *s = VIRTIO_BALLOON(vdev); + + if (!s->stats_vq_elem && vdev->vm_running && + (status & VIRTIO_CONFIG_S_DRIVER_OK) && virtqueue_rewind(s->svq, 1)) { + /* poll stats queue for the element we have discarded when the VM + * was stopped */ + virtio_balloon_receive_stats(vdev, s->svq); + } +} + static void virtio_balloon_instance_init(Object *obj) { VirtIOBalloon *s = VIRTIO_BALLOON(obj); @@ -506,6 +518,7 @@ static void virtio_balloon_class_init(ObjectClass *klass, void *data) vdc->get_features = virtio_balloon_get_features; vdc->save = virtio_balloon_save_device; vdc->load = virtio_balloon_load_device; + vdc->set_status = virtio_balloon_set_status; } static const TypeInfo virtio_balloon_info = {