To use the generic device the user will need to provide the config region size via the command line. We also add a notifier so the guest can be pinged if the remote daemon updates the config.
With these changes: -device vhost-user-device-pci,virtio-id=41,num_vqs=2,config_size=8 is equivalent to: -device vhost-user-gpio-pci Signed-off-by: Alex Bennée <alex.ben...@linaro.org> --- include/hw/virtio/vhost-user-device.h | 1 + hw/virtio/vhost-user-device.c | 58 ++++++++++++++++++++++++++- 2 files changed, 58 insertions(+), 1 deletion(-) diff --git a/include/hw/virtio/vhost-user-device.h b/include/hw/virtio/vhost-user-device.h index 8d77f06721..cb98e0dcaa 100644 --- a/include/hw/virtio/vhost-user-device.h +++ b/include/hw/virtio/vhost-user-device.h @@ -21,6 +21,7 @@ struct VHostUserDevice { CharBackend chardev; uint16_t virtio_id; uint32_t num_vqs; + uint32_t config_size; /* State tracking */ VhostUserState vhost_user; struct vhost_virtqueue *vhost_vq; diff --git a/hw/virtio/vhost-user-device.c b/hw/virtio/vhost-user-device.c index bfbf3b29cb..977cfed247 100644 --- a/hw/virtio/vhost-user-device.c +++ b/hw/virtio/vhost-user-device.c @@ -117,6 +117,42 @@ static uint64_t vud_get_features(VirtIODevice *vdev, return vud->vhost_dev.features & ~(1ULL << VHOST_USER_F_PROTOCOL_FEATURES); } +/* + * To handle VirtIO config we need to know the size of the config + * space. We don't cache the config but re-fetch it from the guest + * every time in case something has changed. + */ +static void vud_get_config(VirtIODevice *vdev, uint8_t *config) +{ + VHostUserDevice *vud = VHOST_USER_DEVICE(vdev); + Error *local_err = NULL; + + /* + * There will have been a warning during vhost_dev_init, but lets + * assert here as nothing will go right now. + */ + g_assert(vud->config_size && vud->vhost_user.supports_config == true); + + if (vhost_dev_get_config(&vud->vhost_dev, config, + vud->config_size, &local_err)) { + error_report_err(local_err); + } +} + +/* + * When the daemon signals an update to the config we just need to + * signal the guest as we re-read the config on demand above. + */ +static int vud_config_notifier(struct vhost_dev *dev) +{ + virtio_notify_config(dev->vdev); + return 0; +} + +const VhostDevConfigOps vud_config_ops = { + .vhost_dev_config_notifier = vud_config_notifier, +}; + static void vud_handle_output(VirtIODevice *vdev, VirtQueue *vq) { /* @@ -141,12 +177,21 @@ static int vud_connect(DeviceState *dev) { VirtIODevice *vdev = VIRTIO_DEVICE(dev); VHostUserDevice *vud = VHOST_USER_DEVICE(vdev); + struct vhost_dev *vhost_dev = &vud->vhost_dev; if (vud->connected) { return 0; } vud->connected = true; + /* + * If we support VHOST_USER_GET_CONFIG we must enable the notifier + * so we can ping the guest when it updates. + */ + if (vud->vhost_user.supports_config) { + vhost_dev_set_config_notifier(vhost_dev, &vud_config_ops); + } + /* restore vhost state */ if (virtio_device_started(vdev, vdev->status)) { vud_start(vdev); @@ -214,11 +259,20 @@ static void vud_device_realize(DeviceState *dev, Error **errp) vud->num_vqs = 1; /* reasonable default? */ } + /* + * We can't handle config requests unless we know the size of the + * config region, specialisations of the vhost-user-device will be + * able to set this. + */ + if (vud->config_size) { + vud->vhost_user.supports_config = true; + } + if (!vhost_user_init(&vud->vhost_user, &vud->chardev, errp)) { return; } - virtio_init(vdev, vud->virtio_id, 0); + virtio_init(vdev, vud->virtio_id, vud->config_size); /* * Disable guest notifiers, by default all notifications will be via the @@ -271,6 +325,7 @@ static Property vud_properties[] = { DEFINE_PROP_CHR("chardev", VHostUserDevice, chardev), DEFINE_PROP_UINT16("virtio-id", VHostUserDevice, virtio_id, 0), DEFINE_PROP_UINT32("num_vqs", VHostUserDevice, num_vqs, 1), + DEFINE_PROP_UINT32("config_size", VHostUserDevice, config_size, 0), DEFINE_PROP_END_OF_LIST(), }; @@ -285,6 +340,7 @@ static void vud_class_init(ObjectClass *klass, void *data) vdc->realize = vud_device_realize; vdc->unrealize = vud_device_unrealize; vdc->get_features = vud_get_features; + vdc->get_config = vud_get_config; vdc->set_status = vud_set_status; } -- 2.39.2