From patchwork Mon Aug 15 12:54:15 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Hajnoczi X-Patchwork-Id: 9280947 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 886DA60780 for ; Mon, 15 Aug 2016 13:04:00 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 78FE427FA8 for ; Mon, 15 Aug 2016 13:04:00 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 6DD0228C7A; Mon, 15 Aug 2016 13:04:00 +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 DBFDB27FA8 for ; Mon, 15 Aug 2016 13:03:59 +0000 (UTC) Received: from localhost ([::1]:36844 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bZHYc-0004kq-MZ for patchwork-qemu-devel@patchwork.kernel.org; Mon, 15 Aug 2016 09:03:58 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:42977) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bZHPP-0005GE-M6 for qemu-devel@nongnu.org; Mon, 15 Aug 2016 08:54:28 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bZHPJ-0005d4-Io for qemu-devel@nongnu.org; Mon, 15 Aug 2016 08:54:27 -0400 Received: from mx1.redhat.com ([209.132.183.28]:40646) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bZHPJ-0005cr-Cz for qemu-devel@nongnu.org; Mon, 15 Aug 2016 08:54:21 -0400 Received: from int-mx14.intmail.prod.int.phx2.redhat.com (int-mx14.intmail.prod.int.phx2.redhat.com [10.5.11.27]) (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 BF37F81110; Mon, 15 Aug 2016 12:54:20 +0000 (UTC) Received: from localhost (ovpn-112-36.ams2.redhat.com [10.36.112.36]) by int-mx14.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id u7FCsJwj007924; Mon, 15 Aug 2016 08:54:20 -0400 From: Stefan Hajnoczi To: qemu-devel@nongnu.org Date: Mon, 15 Aug 2016 13:54:15 +0100 Message-Id: <1471265656-11227-2-git-send-email-stefanha@redhat.com> In-Reply-To: <1471265656-11227-1-git-send-email-stefanha@redhat.com> References: <1471265656-11227-1-git-send-email-stefanha@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.27 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.27]); Mon, 15 Aug 2016 12:54:20 +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 1/2] virtio: recalculate vq->inuse after 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: Cornelia Huck , Fam Zheng , Stefan Hajnoczi , "Michael S. Tsirkin" Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Virus-Scanned: ClamAV using ClamSMTP The vq->inuse field is not migrated. Many devices don't hold VirtQueueElements across migration so it doesn't matter that vq->inuse starts at 0 on the destination QEMU. At least virtio-serial, virtio-blk, and virtio-balloon migrate while holding VirtQueueElements. For these devices we need to recalculate vq->inuse upon load so the value is correct. Signed-off-by: Stefan Hajnoczi Reviewed-by: Michael S. Tsirkin Reviewed-by: Cornelia Huck --- hw/virtio/virtio.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c index 15ee3a7..6105c6e 100644 --- a/hw/virtio/virtio.c +++ b/hw/virtio/virtio.c @@ -1648,6 +1648,21 @@ int virtio_load(VirtIODevice *vdev, QEMUFile *f, int version_id) } vdev->vq[i].used_idx = vring_used_idx(&vdev->vq[i]); vdev->vq[i].shadow_avail_idx = vring_avail_idx(&vdev->vq[i]); + + /* + * Some devices migrate VirtQueueElements that have been popped + * from the avail ring but not yet returned to the used ring. + */ + vdev->vq[i].inuse = vdev->vq[i].last_avail_idx - + vdev->vq[i].used_idx; + if (vdev->vq[i].inuse > vdev->vq[i].vring.num) { + error_report("VQ %d size 0x%x < last_avail_idx 0x%x - " + "used_idx 0x%x", + i, vdev->vq[i].vring.num, + vdev->vq[i].last_avail_idx, + vdev->vq[i].used_idx); + return -1; + } } }