Hi Michael, Unfortunately your approach will not work, because the VirtIONet::curr_guest_offloads would still be reset in virtio_net_set_features: -- if (n->has_vnet_hdr) { n->curr_guest_offloads = virtio_net_guest_offloads_by_features(features); -- ( https://github.com/qemu/qemu/blob/master/hw/net/virtio-net.c#L774 )
I.e. although virtio_net_apply_guest_offloads would now be called after the virtio_net_set_features, by the time it is called the VirtIONet::curr_guest_offloads would be reset to a full list of features. Regards, Mikhail Am Do., 10. Okt. 2019 um 20:04 Uhr schrieb Michael S. Tsirkin <m...@redhat.com>: > > Currently offloads disabled by guest via the > VIRTIO_NET_CTRL_GUEST_OFFLOADS_SET > command are not preserved on VM migration. > Instead all offloads reported by guest features (via > VIRTIO_PCI_GUEST_FEATURES) > get enabled. > What happens is: first the VirtIONet::curr_guest_offloads gets restored > and offloads are getting set correctly: > > #0 qemu_set_offload (nc=0x555556a11400, csum=1, tso4=0, tso6=0, ecn=0, > ufo=0) at net/net.c:474 > #1 virtio_net_apply_guest_offloads (n=0x555557701ca0) at > hw/net/virtio-net.c:720 > #2 virtio_net_post_load_device (opaque=0x555557701ca0, version_id=11) at > hw/net/virtio-net.c:2334 > #3 vmstate_load_state (f=0x5555569dc010, vmsd=0x555556577c80 > <vmstate_virtio_net_device>, opaque=0x555557701ca0, version_id=11) > at migration/vmstate.c:168 > #4 virtio_load (vdev=0x555557701ca0, f=0x5555569dc010, version_id=11) at > hw/virtio/virtio.c:2197 > #5 virtio_device_get (f=0x5555569dc010, opaque=0x555557701ca0, size=0, > field=0x55555668cd00 <__compound_literal.5>) at hw/virtio/virtio.c:2036 > #6 vmstate_load_state (f=0x5555569dc010, vmsd=0x555556577ce0 > <vmstate_virtio_net>, opaque=0x555557701ca0, version_id=11) at > migration/vmstate.c:143 > #7 vmstate_load (f=0x5555569dc010, se=0x5555578189e0) at > migration/savevm.c:829 > #8 qemu_loadvm_section_start_full (f=0x5555569dc010, mis=0x5555569eee20) at > migration/savevm.c:2211 > #9 qemu_loadvm_state_main (f=0x5555569dc010, mis=0x5555569eee20) at > migration/savevm.c:2395 > #10 qemu_loadvm_state (f=0x5555569dc010) at migration/savevm.c:2467 > #11 process_incoming_migration_co (opaque=0x0) at migration/migration.c:449 > > However later on the features are getting restored, and offloads get reset to > everything supported by features: > > #0 qemu_set_offload (nc=0x555556a11400, csum=1, tso4=1, tso6=1, ecn=0, > ufo=0) at net/net.c:474 > #1 virtio_net_apply_guest_offloads (n=0x555557701ca0) at > hw/net/virtio-net.c:720 > #2 virtio_net_set_features (vdev=0x555557701ca0, features=5104441767) at > hw/net/virtio-net.c:773 > #3 virtio_set_features_nocheck (vdev=0x555557701ca0, val=5104441767) at > hw/virtio/virtio.c:2052 > #4 virtio_load (vdev=0x555557701ca0, f=0x5555569dc010, version_id=11) at > hw/virtio/virtio.c:2220 > #5 virtio_device_get (f=0x5555569dc010, opaque=0x555557701ca0, size=0, > field=0x55555668cd00 <__compound_literal.5>) at hw/virtio/virtio.c:2036 > #6 vmstate_load_state (f=0x5555569dc010, vmsd=0x555556577ce0 > <vmstate_virtio_net>, opaque=0x555557701ca0, version_id=11) at > migration/vmstate.c:143 > #7 vmstate_load (f=0x5555569dc010, se=0x5555578189e0) at > migration/savevm.c:829 > #8 qemu_loadvm_section_start_full (f=0x5555569dc010, mis=0x5555569eee20) at > migration/savevm.c:2211 > #9 qemu_loadvm_state_main (f=0x5555569dc010, mis=0x5555569eee20) at > migration/savevm.c:2395 > #10 qemu_loadvm_state (f=0x5555569dc010) at migration/savevm.c:2467 > #11 process_incoming_migration_co (opaque=0x0) at migration/migration.c:449 > > Fix this by pushing out offload initialization to the new post load hook. > > Reported-by: Mikhail Sennikovsky <mikhail.sennikovs...@cloud.ionos.com> > Signed-off-by: Michael S. Tsirkin <m...@redhat.com> > --- > hw/net/virtio-net.c | 14 ++++++++++---- > 1 file changed, 10 insertions(+), 4 deletions(-) > > diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c > index 9f11422337..62fb858e2d 100644 > --- a/hw/net/virtio-net.c > +++ b/hw/net/virtio-net.c > @@ -2333,10 +2333,6 @@ static int virtio_net_post_load_device(void *opaque, > int version_id) > n->curr_guest_offloads = virtio_net_supported_guest_offloads(n); > } > > - if (peer_has_vnet_hdr(n)) { > - virtio_net_apply_guest_offloads(n); > - } > - > virtio_net_set_queues(n); > > /* Find the first multicast entry in the saved MAC filter */ > @@ -2370,6 +2366,15 @@ static int virtio_net_post_load_device(void *opaque, > int version_id) > return 0; > } > > +static int virtio_net_post_load_virtio(VirtIODevice *vdev) > +{ > + if (peer_has_vnet_hdr(n)) { > + virtio_net_apply_guest_offloads(n); > + } > + > + return 0; > +} > + > /* tx_waiting field of a VirtIONetQueue */ > static const VMStateDescription vmstate_virtio_net_queue_tx_waiting = { > .name = "virtio-net-queue-tx_waiting", > @@ -2912,6 +2917,7 @@ static void virtio_net_class_init(ObjectClass *klass, > void *data) > vdc->guest_notifier_mask = virtio_net_guest_notifier_mask; > vdc->guest_notifier_pending = virtio_net_guest_notifier_pending; > vdc->legacy_features |= (0x1 << VIRTIO_NET_F_GSO); > + vdc->post_load = virtio_net_post_load_virtio; > vdc->vmsd = &vmstate_virtio_net_device; > } > > -- > MST >