Re: [PATCH] virtio-net: vhost-user: Implement internal migration

[Laurent Vivier <lvivier@redhat.com>]

On 15/01/2025 11:10, Michael S. Tsirkin wrote:
> On Wed, Dec 18, 2024 at 03:34:53PM +0100, Laurent Vivier wrote:
>> Add support of VHOST_USER_PROTOCOL_F_DEVICE_STATE in virtio-net
>> with vhost-user backend.
>>
>> Cc: Hanna Czenczek <hreitz@redhat.com>
>> Signed-off-by: Laurent Vivier <lvivier@redhat.com>
> 
> 
> Breaks windows builds:
> 
> https://gitlab.com/mstredhat/qemu/-/jobs/8855973625

Thank you Michael.

I fix that, test and send new version soon.

Laurent
> 
>> ---
>>   hw/net/virtio-net.c | 135 ++++++++++++++++++++++++++++++++++++--------
>>   1 file changed, 112 insertions(+), 23 deletions(-)
>>
>> diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
>> index 6e8c51a2dbce..b4d9e96dc0d7 100644
>> --- a/hw/net/virtio-net.c
>> +++ b/hw/net/virtio-net.c
>> @@ -3337,6 +3337,117 @@ static const VMStateDescription vmstate_virtio_net_rss = {
>>       },
>>   };
>>   
>> +static struct vhost_dev *virtio_net_get_vhost(VirtIODevice *vdev)
>> +{
>> +    VirtIONet *n = VIRTIO_NET(vdev);
>> +    NetClientState *nc;
>> +    struct vhost_net *net;
>> +
>> +    if (!n->nic) {
>> +        return NULL;
>> +    }
>> +
>> +    nc = qemu_get_queue(n->nic);
>> +    if (!nc) {
>> +        return NULL;
>> +    }
>> +
>> +    net = get_vhost_net(nc->peer);
>> +    if (!net) {
>> +        return NULL;
>> +    }
>> +
>> +    return &net->dev;
>> +}
>> +
>> +static int vhost_user_net_save_state(QEMUFile *f, void *pv, size_t size,
>> +                                     const VMStateField *field,
>> +                                     JSONWriter *vmdesc)
>> +{
>> +    VirtIONet *n = pv;
>> +    VirtIODevice *vdev = VIRTIO_DEVICE(n);
>> +    struct vhost_dev *vhdev;
>> +    Error *local_error = NULL;
>> +    int ret;
>> +
>> +    vhdev = virtio_net_get_vhost(vdev);
>> +    if (vhdev == NULL) {
>> +        error_reportf_err(local_error,
>> +                          "Error getting vhost back-end of %s device %s: ",
>> +                          vdev->name, vdev->parent_obj.canonical_path);
>> +        return -1;
>> +    }
>> +
>> +    ret = vhost_save_backend_state(vhdev, f, &local_error);
>> +    if (ret < 0) {
>> +        error_reportf_err(local_error,
>> +                          "Error saving back-end state of %s device %s: ",
>> +                          vdev->name, vdev->parent_obj.canonical_path);
>> +        return ret;
>> +    }
>> +
>> +    return 0;
>> +}
>> +
>> +static int vhost_user_net_load_state(QEMUFile *f, void *pv, size_t size,
>> +                                     const VMStateField *field)
>> +{
>> +    VirtIONet *n = pv;
>> +    VirtIODevice *vdev = VIRTIO_DEVICE(n);
>> +    struct vhost_dev *vhdev;
>> +    Error *local_error = NULL;
>> +    int ret;
>> +
>> +    vhdev = virtio_net_get_vhost(vdev);
>> +    if (vhdev == NULL) {
>> +        error_reportf_err(local_error,
>> +                          "Error getting vhost back-end of %s device %s: ",
>> +                          vdev->name, vdev->parent_obj.canonical_path);
>> +        return -1;
>> +    }
>> +
>> +    ret = vhost_load_backend_state(vhdev, f, &local_error);
>> +    if (ret < 0) {
>> +        error_reportf_err(local_error,
>> +                          "Error loading  back-end state of %s device %s: ",
>> +                          vdev->name, vdev->parent_obj.canonical_path);
>> +        return ret;
>> +    }
>> +
>> +    return 0;
>> +}
>> +
>> +static bool vhost_user_net_is_internal_migration(void *opaque)
>> +{
>> +    VirtIONet *n = opaque;
>> +    VirtIODevice *vdev = VIRTIO_DEVICE(n);
>> +    struct vhost_dev *vhdev;
>> +
>> +    vhdev = virtio_net_get_vhost(vdev);
>> +    if (vhdev == NULL) {
>> +        return false;
>> +    }
>> +
>> +    return vhost_supports_device_state(vhdev);
>> +}
>> +
>> +static const VMStateDescription vhost_user_net_backend_state = {
>> +    .name = "virtio-net-device/backend",
>> +    .version_id = 0,
>> +    .needed = vhost_user_net_is_internal_migration,
>> +    .fields = (const VMStateField[]) {
>> +        {
>> +            .name = "backend",
>> +            .info = &(const VMStateInfo) {
>> +                .name = "virtio-net vhost-user backend state",
>> +                .get = vhost_user_net_load_state,
>> +                .put = vhost_user_net_save_state,
>> +            },
>> +         },
>> +         VMSTATE_END_OF_LIST()
>> +    }
>> +};
>> +
>>   static const VMStateDescription vmstate_virtio_net_device = {
>>       .name = "virtio-net-device",
>>       .version_id = VIRTIO_NET_VM_VERSION,
>> @@ -3389,6 +3500,7 @@ static const VMStateDescription vmstate_virtio_net_device = {
>>       },
>>       .subsections = (const VMStateDescription * const []) {
>>           &vmstate_virtio_net_rss,
>> +        &vhost_user_net_backend_state,
>>           NULL
>>       }
>>   };
>> @@ -3950,29 +4062,6 @@ static bool dev_unplug_pending(void *opaque)
>>       return vdc->primary_unplug_pending(dev);
>>   }
>>   
>> -static struct vhost_dev *virtio_net_get_vhost(VirtIODevice *vdev)
>> -{
>> -    VirtIONet *n = VIRTIO_NET(vdev);
>> -    NetClientState *nc;
>> -    struct vhost_net *net;
>> -
>> -    if (!n->nic) {
>> -        return NULL;
>> -    }
>> -
>> -    nc = qemu_get_queue(n->nic);
>> -    if (!nc) {
>> -        return NULL;
>> -    }
>> -
>> -    net = get_vhost_net(nc->peer);
>> -    if (!net) {
>> -        return NULL;
>> -    }
>> -
>> -    return &net->dev;
>> -}
>> -
>>   static const VMStateDescription vmstate_virtio_net = {
>>       .name = "virtio-net",
>>       .minimum_version_id = VIRTIO_NET_VM_VERSION,
>> -- 
>> 2.47.1
>