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Violators will be prosecuted; Mon, 20 Mar 2017 17:09:27 -0600 Received: from b03ledav005.gho.boulder.ibm.com (b03ledav005.gho.boulder.ibm.com [9.17.130.236]) by b03cxnp08025.gho.boulder.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id v2KN9RD011469090; Mon, 20 Mar 2017 16:09:27 -0700 Received: from b03ledav005.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id E6ACEBE040; Mon, 20 Mar 2017 17:09:26 -0600 (MDT) Received: from localhost (unknown [9.53.92.194]) by b03ledav005.gho.boulder.ibm.com (Postfix) with ESMTP id C7810BE03E; Mon, 20 Mar 2017 17:09:26 -0600 (MDT) From: Michael Roth To: qemu-devel@nongnu.org Date: Mon, 20 Mar 2017 18:08:02 -0500 X-Mailer: git-send-email 2.7.4 In-Reply-To: <1490051325-3770-1-git-send-email-mdroth@linux.vnet.ibm.com> References: <1490051325-3770-1-git-send-email-mdroth@linux.vnet.ibm.com> X-TM-AS-GCONF: 00 x-cbid: 17032023-0028-0000-0000-00000740CEF7 X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00006819; HX=3.00000240; KW=3.00000007; PH=3.00000004; SC=3.00000206; SDB=6.00836553; UDB=6.00411161; IPR=6.00614321; BA=6.00005224; NDR=6.00000001; ZLA=6.00000005; ZF=6.00000009; ZB=6.00000000; ZP=6.00000000; ZH=6.00000000; ZU=6.00000002; MB=3.00014732; XFM=3.00000013; UTC=2017-03-20 23:09:29 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17032023-0029-0000-0000-00003472528D Message-Id: <1490051325-3770-39-git-send-email-mdroth@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:, , definitions=2017-03-20_16:, , signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=1 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1702020001 definitions=main-1703200196 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x [generic] [fuzzy] X-Received-From: 148.163.156.1 Subject: [Qemu-devel] [PATCH 38/81] virtio: fix vq->inuse recalc after migr 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: Halil Pasic , qemu-stable@nongnu.org, "Michael S . Tsirkin" Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" From: Halil Pasic Correct recalculation of vq->inuse after migration for the corner case where the avail_idx has already wrapped but used_idx not yet. Also change the type of the VirtQueue.inuse to unsigned int. This is done to be consistent with other members representing sizes (VRing.num), and because C99 guarantees max ring size < UINT_MAX but does not guarantee max ring size < INT_MAX. Signed-off-by: Halil Pasic Fixes: bccdef6b ("virtio: recalculate vq->inuse after migration") CC: qemu-stable@nongnu.org Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin Reviewed-by: Stefan Hajnoczi (cherry picked from commit e66bcc408146730958d1a840bda85d7ad51e0cd7) Signed-off-by: Michael Roth --- hw/virtio/virtio.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c index 1af2de2..e37641a 100644 --- a/hw/virtio/virtio.c +++ b/hw/virtio/virtio.c @@ -92,7 +92,7 @@ struct VirtQueue =20 uint16_t queue_index; =20 - int inuse; + unsigned int inuse; =20 uint16_t vector; VirtIOHandleOutput handle_output; @@ -1855,9 +1855,11 @@ int virtio_load(VirtIODevice *vdev, QEMUFile *f, int= version_id) /* * Some devices migrate VirtQueueElements that have been popped * from the avail ring but not yet returned to the used ring. + * Since max ring size < UINT16_MAX it's safe to use modulo + * UINT16_MAX + 1 subtraction. */ - vdev->vq[i].inuse =3D vdev->vq[i].last_avail_idx - - vdev->vq[i].used_idx; + vdev->vq[i].inuse =3D (uint16_t)(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", --=20 2.7.4