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envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=205.220.165.32; envelope-from=jonah.palmer@oracle.com; helo=mx0a-00069f02.pphosted.com X-Spam_score_int: -10 X-Spam_score: -1.1 X-Spam_bar: - X-Spam_report: (-1.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_MED=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.819, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.903, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: qemu development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZohoMail-DKIM: pass (identity @oracle.com) X-ZM-MESSAGEID: 1774016578950158500 Content-Type: text/plain; charset="utf-8" This patch introduces the mechanism in which this series will use to detect VirtIODevice & VirtIONet state deltas, starting with the VirtIODevice's 'status' member of a virtio-net device. Before we send the device's state early, we save each piece of its state in a temporary structure via virtio_net_early_pre_save. Later, once the source VM has been paused, we compare the current values of those pieces to what we saved earlier. If any mismatch is found, virtio-net's VMSD (vmstate_virtio_net) is enabled and resends all state and device prep work (as it's normally done today when live migrating a virtio-net device). Once all relevant delta checks are in place, a no-delta case will skip vmstate_virtio_net and only resend updated VQ indices. For this patch, keep a temporary always-true fallback in virtio_net_has_delta/virtio_net_needed until follow-up patches cover the remaining VirtIONet & VirtIODevice deltas. Signed-off-by: Jonah Palmer --- hw/net/virtio-net.c | 40 ++++++++++++++++++++++++++++++++++++++ include/hw/virtio/virtio.h | 2 ++ 2 files changed, 42 insertions(+) diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c index 5d71ad235e..2733e0130c 100644 --- a/hw/net/virtio-net.c +++ b/hw/net/virtio-net.c @@ -3864,6 +3864,16 @@ static bool failover_hide_primary_device(DeviceListe= ner *listener, return qatomic_read(&n->failover_primary_hidden); } =20 +static int virtio_net_early_pre_save(void *opaque) +{ + VirtIONet *n =3D opaque; + VirtIODevice *vdev =3D VIRTIO_DEVICE(n); + VirtIODevMigration *vdev_mig =3D vdev->migration; + + vdev_mig->status_early =3D vdev->status; + return 0; +} + static int virtio_net_early_pre_load(void *opaque) { VirtIONet *n =3D opaque; @@ -3887,6 +3897,7 @@ static const VMStateDescription vmstate_virtio_net_ea= rly =3D { .minimum_version_id =3D VIRTIO_NET_VM_VERSION, .version_id =3D VIRTIO_NET_VM_VERSION, .early_setup =3D true, + .pre_save =3D virtio_net_early_pre_save, .pre_load =3D virtio_net_early_pre_load, .post_load =3D virtio_net_early_post_load, .fields =3D (const VMStateField[]) { @@ -4231,10 +4242,39 @@ static bool dev_unplug_pending(void *opaque) return vdc->primary_unplug_pending(dev); } =20 +static bool virtio_net_has_delta(VirtIONet *n, VirtIODevice *vdev) +{ + VirtIODevMigration *vdev_mig =3D vdev->migration; + + /* Has the VirtIODevice's status changed? */ + if (vdev->status !=3D vdev_mig->status_early) { + return true; + } + + /* + * Always return true for now until we're able to detect all possible + * changes to a VirtIONet device. + */ + return true; +} + +static bool virtio_net_needed(void *opaque) +{ + VirtIONet *n =3D opaque; + VirtIODevice *vdev =3D VIRTIO_DEVICE(n); + + if (!n->early_mig) { + return true; + } + + return virtio_net_has_delta(n, vdev); +} + static const VMStateDescription vmstate_virtio_net =3D { .name =3D "virtio-net", .minimum_version_id =3D VIRTIO_NET_VM_VERSION, .version_id =3D VIRTIO_NET_VM_VERSION, + .needed =3D virtio_net_needed, .fields =3D (const VMStateField[]) { VMSTATE_VIRTIO_DEVICE, VMSTATE_END_OF_LIST() diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h index 74fed8c324..752c46ce53 100644 --- a/include/hw/virtio/virtio.h +++ b/include/hw/virtio/virtio.h @@ -102,9 +102,11 @@ enum virtio_device_endian { /** * struct VirtIODevMigration - Common VirtIODevice migration structure * @early_load: Flag to indicate an early virtio_load for the device. + * @status_early: Device status at the time it was sent early. */ typedef struct VirtIODevMigration { bool early_load; + uint8_t status_early; } VirtIODevMigration; =20 /** --=20 2.51.0