diff options
| -rw-r--r-- | include/hw/virtio/vhost.h | 25 | ||||
| -rw-r--r-- | include/hw/virtio/virtio.h | 19 |
2 files changed, 40 insertions, 4 deletions
diff --git a/include/hw/virtio/vhost.h b/include/hw/virtio/vhost.h index 67a6807fac..1cafa0d776 100644 --- a/include/hw/virtio/vhost.h +++ b/include/hw/virtio/vhost.h @@ -88,13 +88,32 @@ struct vhost_dev { int vq_index_end; /* if non-zero, minimum required value for max_queues */ int num_queues; + /** + * vhost feature handling requires matching the feature set + * offered by a backend which may be a subset of the total + * features eventually offered to the guest. + * + * @features: available features provided by the backend + * @acked_features: final negotiated features with front-end driver + * + * @backend_features: this is used in a couple of places to either + * store VHOST_USER_F_PROTOCOL_FEATURES to apply to + * VHOST_USER_SET_FEATURES or VHOST_NET_F_VIRTIO_NET_HDR. Its + * future use should be discouraged and the variable retired as + * its easy to confuse with the VirtIO backend_features. + */ uint64_t features; - /** @acked_features: final set of negotiated features */ uint64_t acked_features; - /** @backend_features: backend specific feature bits */ uint64_t backend_features; - /** @protocol_features: final negotiated protocol features */ + + /** + * @protocol_features: is the vhost-user only feature set by + * VHOST_USER_SET_PROTOCOL_FEATURES. Protocol features are only + * negotiated if VHOST_USER_F_PROTOCOL_FEATURES has been offered + * by the backend (see @features). + */ uint64_t protocol_features; + uint64_t max_queues; uint64_t backend_cap; /* @started: is the vhost device started? */ diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h index acfd4df125..24561e933a 100644 --- a/include/hw/virtio/virtio.h +++ b/include/hw/virtio/virtio.h @@ -93,6 +93,12 @@ enum virtio_device_endian { VIRTIO_DEVICE_ENDIAN_BIG, }; +/** + * struct VirtIODevice - common VirtIO structure + * @name: name of the device + * @status: VirtIO Device Status field + * + */ struct VirtIODevice { DeviceState parent_obj; @@ -100,9 +106,20 @@ struct VirtIODevice uint8_t status; uint8_t isr; uint16_t queue_sel; - uint64_t guest_features; + /** + * These fields represent a set of VirtIO features at various + * levels of the stack. @host_features indicates the complete + * feature set the VirtIO device can offer to the driver. + * @guest_features indicates which features the VirtIO driver has + * selected by writing to the feature register. Finally + * @backend_features represents everything supported by the + * backend (e.g. vhost) and could potentially be a subset of the + * total feature set offered by QEMU. + */ uint64_t host_features; + uint64_t guest_features; uint64_t backend_features; + size_t config_len; void *config; uint16_t config_vector; |