Re: [Qemu-devel] [PATCH] virtio-net: unbreak self announcement and guest offloads after migration

2015-09-16 Thread Greg Kurz 
On Fri, 11 Sep 2015 16:01:56 +0800
Jason Wang  wrote:

> After commit 019a3edbb25f1571e876f8af1ce4c55412939e5d ("virtio: make
> features 64bit wide"). Device's guest_features was actually set after
> vdc->load(). This breaks the assumption that device specific load()

Yeah... subsections are loaded after the device specific state...

> function can check guest_features. For virtio-net, self announcement
> and guest offloads won't work after migration.
> 
> Fixing this by defer them to virtio_net_load() where guest_features
> were guaranteed to be set. Other virtio devices looks fine.
> 
> Fixes: 019a3edbb25f1571e876f8af1ce4c55412939e5d
>("virtio: make features 64bit wide")
> Cc: qemu-sta...@nongnu.org
> Cc: Gerd Hoffmann 
> Signed-off-by: Jason Wang 
> ---

Reviewed-by: Greg Kurz 

>  hw/net/virtio-net.c | 40 +++-
>  1 file changed, 23 insertions(+), 17 deletions(-)
> 
> diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
> index f72eebf..2775e6a 100644
> --- a/hw/net/virtio-net.c
> +++ b/hw/net/virtio-net.c
> @@ -1458,11 +1458,33 @@ static int virtio_net_load(QEMUFile *f, void *opaque, 
> int version_id)
>  {
>  VirtIONet *n = opaque;
>  VirtIODevice *vdev = VIRTIO_DEVICE(n);
> +int ret;
> 
>  if (version_id < 2 || version_id > VIRTIO_NET_VM_VERSION)
>  return -EINVAL;
> 
> -return virtio_load(vdev, f, version_id);
> +ret = virtio_load(vdev, f, version_id);
> +if (ret) {
> +return ret;
> +}
> +
> +if (virtio_vdev_has_feature(vdev, VIRTIO_NET_F_CTRL_GUEST_OFFLOADS)) {
> +n->curr_guest_offloads = qemu_get_be64(f);
> +} else {
> +n->curr_guest_offloads = virtio_net_supported_guest_offloads(n);
> +}
> +
> +if (peer_has_vnet_hdr(n)) {
> +virtio_net_apply_guest_offloads(n);
> +}
> +
> +if (virtio_vdev_has_feature(vdev, VIRTIO_NET_F_GUEST_ANNOUNCE) &&
> +virtio_vdev_has_feature(vdev, VIRTIO_NET_F_CTRL_VQ)) {
> +n->announce_counter = SELF_ANNOUNCE_ROUNDS;
> +timer_mod(n->announce_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL));
> +}
> +
> +return 0;
>  }
> 
>  static int virtio_net_load_device(VirtIODevice *vdev, QEMUFile *f,
> @@ -1559,16 +1581,6 @@ static int virtio_net_load_device(VirtIODevice *vdev, 
> QEMUFile *f,
>  }
>  }
> 
> -if (virtio_vdev_has_feature(vdev, VIRTIO_NET_F_CTRL_GUEST_OFFLOADS)) {
> -n->curr_guest_offloads = qemu_get_be64(f);
> -} else {
> -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 */
> @@ -1586,12 +1598,6 @@ static int virtio_net_load_device(VirtIODevice *vdev, 
> QEMUFile *f,
>  qemu_get_subqueue(n->nic, i)->link_down = link_down;
>  }
> 
> -if (virtio_vdev_has_feature(vdev, VIRTIO_NET_F_GUEST_ANNOUNCE) &&
> -virtio_vdev_has_feature(vdev, VIRTIO_NET_F_CTRL_VQ)) {
> -n->announce_counter = SELF_ANNOUNCE_ROUNDS;
> -timer_mod(n->announce_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL));
> -}
> -
>  return 0;
>  }
>

Re: [Qemu-devel] [PATCH] virtio-net: unbreak self announcement and guest offloads after migration

2015-09-16 Thread Greg Kurz 
On Fri, 11 Sep 2015 10:30:21 +0200
Cornelia Huck  wrote:

> On Fri, 11 Sep 2015 16:01:56 +0800
> Jason Wang  wrote:
> 
> > After commit 019a3edbb25f1571e876f8af1ce4c55412939e5d ("virtio: make
> > features 64bit wide"). Device's guest_features was actually set after
> > vdc->load(). This breaks the assumption that device specific load()
> > function can check guest_features. For virtio-net, self announcement
> > and guest offloads won't work after migration.
> > 
> > Fixing this by defer them to virtio_net_load() where guest_features
> > were guaranteed to be set. Other virtio devices looks fine.
> > 
> > Fixes: 019a3edbb25f1571e876f8af1ce4c55412939e5d
> >("virtio: make features 64bit wide")
> > Cc: qemu-sta...@nongnu.org
> > Cc: Gerd Hoffmann 
> > Signed-off-by: Jason Wang 
> > ---
> >  hw/net/virtio-net.c | 40 +++-
> >  1 file changed, 23 insertions(+), 17 deletions(-)
> 
> Migration support for virtio is really a twisty maze, it's easy to make
> mistakes like that :(
> 

We have the very same problem with @device_endian which is also streamed in
a subsection. To prevent early usage on the load path, we set @device_endian
to a poisoned value that triggers assert() in the virtio_is_big_endian() helper.

Should this logic be generalized ?

Re: [Qemu-devel] [PATCH] virtio-net: unbreak self announcement and guest offloads after migration

2015-09-11 Thread Cornelia Huck 
On Fri, 11 Sep 2015 16:01:56 +0800
Jason Wang  wrote:

> After commit 019a3edbb25f1571e876f8af1ce4c55412939e5d ("virtio: make
> features 64bit wide"). Device's guest_features was actually set after
> vdc->load(). This breaks the assumption that device specific load()
> function can check guest_features. For virtio-net, self announcement
> and guest offloads won't work after migration.
> 
> Fixing this by defer them to virtio_net_load() where guest_features
> were guaranteed to be set. Other virtio devices looks fine.
> 
> Fixes: 019a3edbb25f1571e876f8af1ce4c55412939e5d
>("virtio: make features 64bit wide")
> Cc: qemu-sta...@nongnu.org
> Cc: Gerd Hoffmann 
> Signed-off-by: Jason Wang 
> ---
>  hw/net/virtio-net.c | 40 +++-
>  1 file changed, 23 insertions(+), 17 deletions(-)

Migration support for virtio is really a twisty maze, it's easy to make
mistakes like that :(

Reviewed-by: Cornelia Huck

[Qemu-devel] [PATCH] virtio-net: unbreak self announcement and guest offloads after migration

2015-09-11 Thread Jason Wang 
After commit 019a3edbb25f1571e876f8af1ce4c55412939e5d ("virtio: make
features 64bit wide"). Device's guest_features was actually set after
vdc->load(). This breaks the assumption that device specific load()
function can check guest_features. For virtio-net, self announcement
and guest offloads won't work after migration.

Fixing this by defer them to virtio_net_load() where guest_features
were guaranteed to be set. Other virtio devices looks fine.

Fixes: 019a3edbb25f1571e876f8af1ce4c55412939e5d
   ("virtio: make features 64bit wide")
Cc: qemu-sta...@nongnu.org
Cc: Gerd Hoffmann 
Signed-off-by: Jason Wang 
---
 hw/net/virtio-net.c | 40 +++-
 1 file changed, 23 insertions(+), 17 deletions(-)

diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
index f72eebf..2775e6a 100644
--- a/hw/net/virtio-net.c
+++ b/hw/net/virtio-net.c
@@ -1458,11 +1458,33 @@ static int virtio_net_load(QEMUFile *f, void *opaque, 
int version_id)
 {
 VirtIONet *n = opaque;
 VirtIODevice *vdev = VIRTIO_DEVICE(n);
+int ret;
 
 if (version_id < 2 || version_id > VIRTIO_NET_VM_VERSION)
 return -EINVAL;
 
-return virtio_load(vdev, f, version_id);
+ret = virtio_load(vdev, f, version_id);
+if (ret) {
+return ret;
+}
+
+if (virtio_vdev_has_feature(vdev, VIRTIO_NET_F_CTRL_GUEST_OFFLOADS)) {
+n->curr_guest_offloads = qemu_get_be64(f);
+} else {
+n->curr_guest_offloads = virtio_net_supported_guest_offloads(n);
+}
+
+if (peer_has_vnet_hdr(n)) {
+virtio_net_apply_guest_offloads(n);
+}
+
+if (virtio_vdev_has_feature(vdev, VIRTIO_NET_F_GUEST_ANNOUNCE) &&
+virtio_vdev_has_feature(vdev, VIRTIO_NET_F_CTRL_VQ)) {
+n->announce_counter = SELF_ANNOUNCE_ROUNDS;
+timer_mod(n->announce_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL));
+}
+
+return 0;
 }
 
 static int virtio_net_load_device(VirtIODevice *vdev, QEMUFile *f,
@@ -1559,16 +1581,6 @@ static int virtio_net_load_device(VirtIODevice *vdev, 
QEMUFile *f,
 }
 }
 
-if (virtio_vdev_has_feature(vdev, VIRTIO_NET_F_CTRL_GUEST_OFFLOADS)) {
-n->curr_guest_offloads = qemu_get_be64(f);
-} else {
-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 */
@@ -1586,12 +1598,6 @@ static int virtio_net_load_device(VirtIODevice *vdev, 
QEMUFile *f,
 qemu_get_subqueue(n->nic, i)->link_down = link_down;
 }
 
-if (virtio_vdev_has_feature(vdev, VIRTIO_NET_F_GUEST_ANNOUNCE) &&
-virtio_vdev_has_feature(vdev, VIRTIO_NET_F_CTRL_VQ)) {
-n->announce_counter = SELF_ANNOUNCE_ROUNDS;
-timer_mod(n->announce_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL));
-}
-
 return 0;
 }
 
-- 
2.1.4