Hi
On Wed, May 3, 2023 at 12:21 PM Albert Esteve <aest...@redhat.com> wrote:
> Add vu_write_msg_cb type as a member of the VuDev
> struct.
>
> In order to interact with the virtio-dmabuf
> API, vhost-user backends have available a special
> message type that can be sent to the frontend
> in Qemu, in order to add, lookup, or remove
> entries.
>
> To send these messages and avoid code replication,
> backends will need the write_msg method to be exposed
> to them, similarly to how the read_msg is for
> receiving messages.
>
I think read_msg was introduced to blend libvhost-user IO to qemu mainloop
& coroutine. Is that what you have in mind for write_msg?
> Signed-off-by: Albert Esteve <aest...@redhat.com>
> ---
> subprojects/libvhost-user/libvhost-user.c | 1 +
> subprojects/libvhost-user/libvhost-user.h | 16 ++++++++++++++++
> 2 files changed, 17 insertions(+)
>
> diff --git a/subprojects/libvhost-user/libvhost-user.c
> b/subprojects/libvhost-user/libvhost-user.c
> index 6b4b721225..c50b353915 100644
> --- a/subprojects/libvhost-user/libvhost-user.c
> +++ b/subprojects/libvhost-user/libvhost-user.c
> @@ -2115,6 +2115,7 @@ vu_init(VuDev *dev,
> dev->sock = socket;
> dev->panic = panic;
> dev->read_msg = read_msg ? read_msg : vu_message_read_default;
> + dev->write_msg = vu_message_write;
>
You are not making it customizable? And the callback is not used.
> dev->set_watch = set_watch;
> dev->remove_watch = remove_watch;
> dev->iface = iface;
> diff --git a/subprojects/libvhost-user/libvhost-user.h
> b/subprojects/libvhost-user/libvhost-user.h
> index 784db65f7c..f5d7162886 100644
> --- a/subprojects/libvhost-user/libvhost-user.h
> +++ b/subprojects/libvhost-user/libvhost-user.h
> @@ -242,6 +242,7 @@ typedef void (*vu_set_features_cb) (VuDev *dev,
> uint64_t features);
> typedef int (*vu_process_msg_cb) (VuDev *dev, VhostUserMsg *vmsg,
> int *do_reply);
> typedef bool (*vu_read_msg_cb) (VuDev *dev, int sock, VhostUserMsg *vmsg);
> +typedef bool (*vu_write_msg_cb) (VuDev *dev, int sock, VhostUserMsg
> *vmsg);
> typedef void (*vu_queue_set_started_cb) (VuDev *dev, int qidx, bool
> started);
> typedef bool (*vu_queue_is_processed_in_order_cb) (VuDev *dev, int qidx);
> typedef int (*vu_get_config_cb) (VuDev *dev, uint8_t *config, uint32_t
> len);
> @@ -429,6 +430,21 @@ struct VuDev {
> */
> vu_read_msg_cb read_msg;
>
> + /*
> + * @write_msg: custom method to write vhost-user message
> + *
> + * Write data to vhost_user socket fd from the passed
> + * VhostUserMsg *vmsg struct.
> + *
> + * For the details, please refer to vu_message_write in
> libvhost-user.c
> + * which will be used by default when calling vu_unit.
> + * No custom method is allowed.
>
"No custom method is allowed"?
> + *
> + * Returns: true if vhost-user message successfully sent, false
> otherwise.
> + *
> + */
> + vu_write_msg_cb write_msg;
> +
>
--
Marc-André Lureau
