On Wed, Oct 29, 2025 at 02:39:41PM +0500, Alexandr Moshkov wrote:
> Prepare for future inflight region migration for vhost-user-blk.
> We need to migrate size, queue_size, and inner buffer.
>
> So firstly it migrate size and queue_size fields, then allocate memory for
> buffer with
> migrated size, then migrate inner buffer itself.
>
> Signed-off-by: Alexandr Moshkov <[email protected]>
> ---
> hw/virtio/vhost.c | 44 +++++++++++++++++++++++++++++++++++++++
> include/hw/virtio/vhost.h | 6 ++++++
> 2 files changed, 50 insertions(+)
>
> diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
> index c46203eb9c..f0c283f8f4 100644
> --- a/hw/virtio/vhost.c
> +++ b/hw/virtio/vhost.c
> @@ -2028,6 +2028,50 @@ const VMStateDescription
> vmstate_backend_transfer_vhost_inflight = {
> }
> };
>
> +static int vhost_inflight_buffer_pre_load(void *opaque)
> +{
> + info_report("vhost_inflight_region_buffer_pre_load");
> + struct vhost_inflight *inflight = opaque;
> +
> + Error *err = NULL;
> + int fd = -1;
> + void *addr = qemu_memfd_alloc("vhost-inflight", inflight->size,
> + F_SEAL_GROW | F_SEAL_SHRINK | F_SEAL_SEAL,
> + &fd, &err);
> + if (err) {
> + error_report_err(err);
> + return -ENOMEM;
> + }
> +
> + inflight->offset = 0;
> + inflight->addr = addr;
> + inflight->fd = fd;
> +
> + return 0;
> +}
> +
> +const VMStateDescription vmstate_vhost_inflight_region_buffer = {
> + .name = "vhost-inflight-region/buffer",
> + .pre_load = vhost_inflight_buffer_pre_load,
vmsd is much better, thanks.
You can also use pre_load_errp() instead to avoid error_report_err().
> + .fields = (const VMStateField[]) {
> + VMSTATE_VBUFFER_UINT64(addr, struct vhost_inflight, 0, NULL, size),
> + VMSTATE_END_OF_LIST()
> + }
> +};
> +
> +const VMStateDescription vmstate_vhost_inflight_region = {
> + .name = "vhost-inflight-region",
> + .fields = (const VMStateField[]) {
> + VMSTATE_UINT64(size, struct vhost_inflight),
> + VMSTATE_UINT16(queue_size, struct vhost_inflight),
> + VMSTATE_END_OF_LIST()
> + },
> + .subsections = (const VMStateDescription * const []) {
> + &vmstate_vhost_inflight_region_buffer,
> + NULL
> + }
> +};
> +
> const VMStateDescription vmstate_vhost_virtqueue = {
> .name = "vhost-virtqueue",
> .fields = (const VMStateField[]) {
> diff --git a/include/hw/virtio/vhost.h b/include/hw/virtio/vhost.h
> index 13ca2c319f..dd552de91f 100644
> --- a/include/hw/virtio/vhost.h
> +++ b/include/hw/virtio/vhost.h
> @@ -596,6 +596,12 @@ extern const VMStateDescription
> vmstate_backend_transfer_vhost_inflight;
> vmstate_backend_transfer_vhost_inflight, \
> struct vhost_inflight)
>
> +extern const VMStateDescription vmstate_vhost_inflight_region;
> +#define VMSTATE_VHOST_INFLIGHT_REGION(_field, _state) \
> + VMSTATE_STRUCT_POINTER(_field, _state, \
> + vmstate_vhost_inflight_region, \
> + struct vhost_inflight)
> +
> extern const VMStateDescription vmstate_vhost_dev;
> #define VMSTATE_BACKEND_TRANSFER_VHOST(_field, _state) \
> VMSTATE_STRUCT(_field, _state, 0, vmstate_vhost_dev, struct vhost_dev)
> --
> 2.34.1
>
--
Peter Xu
