From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:60228) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1X1IRa-0007yG-5M for qemu-devel@nongnu.org; Sun, 29 Jun 2014 12:59:15 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1X1IRV-0003OY-7B for qemu-devel@nongnu.org; Sun, 29 Jun 2014 12:59:10 -0400 Received: from mx1.redhat.com ([209.132.183.28]:22566) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1X1IRU-0003OM-QP for qemu-devel@nongnu.org; Sun, 29 Jun 2014 12:59:05 -0400 Date: Sun, 29 Jun 2014 19:59:24 +0300 From: "Michael S. Tsirkin" Message-ID: <1404060115-27410-24-git-send-email-mst@redhat.com> References: <1404060115-27410-1-git-send-email-mst@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1404060115-27410-1-git-send-email-mst@redhat.com> Subject: [Qemu-devel] [PULL 23/37] virtio: add subsections to the migration stream List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Peter Maydell , Alexander Graf , Anthony Liguori , Greg Kurz From: Greg Kurz There is a need to add some more fields to VirtIODevice that should be migrated (broken status, endianness). The problem is that we do not want to break compatibility while adding a new feature... This issue has been addressed in the generic VMState code with the use of optional subsections. As a *temporary* alternative to port the whole virtio migration code to VMState, this patch mimics a similar subsectionning ability for virtio, using the VMState code. Since each virtio device is streamed in its own section, the idea is to stream subsections between the end of the device section and the start of the next sections. This allows an older QEMU to complain and exit when fed with subsections: Unknown savevm section type 5 load of migration failed Suggested-by: Alexander Graf Signed-off-by: Greg Kurz Reviewed-by: Alexander Graf Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- hw/virtio/virtio.c | 21 +++++++++++++++++++-- 1 file changed, 19 insertions(+), 2 deletions(-) diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c index 7f9ac5e..7b317ce 100644 --- a/hw/virtio/virtio.c +++ b/hw/virtio/virtio.c @@ -19,6 +19,7 @@ #include "hw/virtio/virtio.h" #include "qemu/atomic.h" #include "hw/virtio/virtio-bus.h" +#include "migration/migration.h" /* * The alignment to use between consumer and producer parts of vring. @@ -839,6 +840,16 @@ void virtio_notify_config(VirtIODevice *vdev) virtio_notify_vector(vdev, vdev->config_vector); } +static const VMStateDescription vmstate_virtio = { + .name = "virtio", + .version_id = 1, + .minimum_version_id = 1, + .minimum_version_id_old = 1, + .fields = (VMStateField[]) { + VMSTATE_END_OF_LIST() + } +}; + void virtio_save(VirtIODevice *vdev, QEMUFile *f) { BusState *qbus = qdev_get_parent_bus(DEVICE(vdev)); @@ -882,6 +893,9 @@ void virtio_save(VirtIODevice *vdev, QEMUFile *f) if (vdc->save != NULL) { vdc->save(vdev, f); } + + /* Subsections */ + vmstate_save_state(f, &vmstate_virtio, vdev); } int virtio_set_features(VirtIODevice *vdev, uint32_t val) @@ -991,10 +1005,13 @@ int virtio_load(VirtIODevice *vdev, QEMUFile *f, int version_id) virtio_notify_vector(vdev, VIRTIO_NO_VECTOR); if (vdc->load != NULL) { - return vdc->load(vdev, f, version_id); + ret = vdc->load(vdev, f, version_id); + if (ret) { + return ret; + } } - return 0; + return vmstate_load_state(f, &vmstate_virtio, vdev, 1); } void virtio_cleanup(VirtIODevice *vdev) -- MST