From patchwork Wed Mar 23 04:10:14 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: [06/18] virtio: decrement last_avail_idx with inuse before saving. From: Yoshiaki Tamura X-Patchwork-Id: 88001 Message-Id: <1300853426-7054-7-git-send-email-tamura.yoshiaki@lab.ntt.co.jp> To: kvm@vger.kernel.org, qemu-devel@nongnu.org Cc: kwolf@redhat.com, aliguori@us.ibm.com, mtosatti@redhat.com, ohmura.kei@lab.ntt.co.jp, ananth@in.ibm.com, mst@redhat.com, dlaor@redhat.com, vatsa@linux.vnet.ibm.com, Yoshiaki Tamura , blauwirbel@gmail.com, quintela@redhat.com, avi@redhat.com, pbonzini@redhat.com, psuriset@linux.vnet.ibm.com, stefanha@linux.vnet.ibm.com Date: Wed, 23 Mar 2011 13:10:14 +0900 For regular migration inuse == 0 always as requests are flushed before save. However, event-tap log when enabled introduces an extra queue for requests which is not being flushed, thus the last inuse requests are left in the event-tap queue. Move the last_avail_idx value sent to the remote back to make it repeat the last inuse requests. Signed-off-by: Michael S. Tsirkin Signed-off-by: Yoshiaki Tamura --- hw/virtio.c | 10 +++++++++- 1 files changed, 9 insertions(+), 1 deletions(-) diff --git a/hw/virtio.c b/hw/virtio.c index 31bd9e3..f05d1b6 100644 --- a/hw/virtio.c +++ b/hw/virtio.c @@ -673,12 +673,20 @@ void virtio_save(VirtIODevice *vdev, QEMUFile *f) qemu_put_be32(f, i); for (i = 0; i < VIRTIO_PCI_QUEUE_MAX; i++) { + /* For regular migration inuse == 0 always as + * requests are flushed before save. However, + * event-tap log when enabled introduces an extra + * queue for requests which is not being flushed, + * thus the last inuse requests are left in the event-tap queue. + * Move the last_avail_idx value sent to the remote back + * to make it repeat the last inuse requests. */ + uint16_t last_avail = vdev->vq[i].last_avail_idx - vdev->vq[i].inuse; if (vdev->vq[i].vring.num == 0) break; qemu_put_be32(f, vdev->vq[i].vring.num); qemu_put_be64(f, vdev->vq[i].pa); - qemu_put_be16s(f, &vdev->vq[i].last_avail_idx); + qemu_put_be16s(f, &last_avail); if (vdev->binding->save_queue) vdev->binding->save_queue(vdev->binding_opaque, i, f); }