On Thu, May 21, 2020 at 7:00 AM Raphael Norwitz <raphael.norwitz@nutanix.com>
wrote:

> The VHOST_USER_GET_MAX_MEM_SLOTS message allows a vhost-user backend to
> specify a maximum number of ram slots it is willing to support. This
> change adds support for libvhost-user to process this message. For now
> the backend will reply with 8 as the maximum number of regions
> supported.
>
> libvhost-user does not yet support the vhost-user protocol feature
> VHOST_USER_PROTOCOL_F_CONFIGIRE_MEM_SLOTS, so qemu should never
> send the VHOST_USER_GET_MAX_MEM_SLOTS message. Therefore this new
> functionality is not currently used.
>
> Signed-off-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
>

Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>

---
>  contrib/libvhost-user/libvhost-user.c | 19 +++++++++++++++++++
>  contrib/libvhost-user/libvhost-user.h |  1 +
>  2 files changed, 20 insertions(+)
>
> diff --git a/contrib/libvhost-user/libvhost-user.c
> b/contrib/libvhost-user/libvhost-user.c
> index cccfa22..9f039b7 100644
> --- a/contrib/libvhost-user/libvhost-user.c
> +++ b/contrib/libvhost-user/libvhost-user.c
> @@ -137,6 +137,7 @@ vu_request_to_string(unsigned int req)
>          REQ(VHOST_USER_SET_INFLIGHT_FD),
>          REQ(VHOST_USER_GPU_SET_SOCKET),
>          REQ(VHOST_USER_VRING_KICK),
> +        REQ(VHOST_USER_GET_MAX_MEM_SLOTS),
>          REQ(VHOST_USER_MAX),
>      };
>  #undef REQ
> @@ -1565,6 +1566,22 @@ vu_handle_vring_kick(VuDev *dev, VhostUserMsg *vmsg)
>      return false;
>  }
>
> +static bool vu_handle_get_max_memslots(VuDev *dev, VhostUserMsg *vmsg)
> +{
> +    vmsg->flags = VHOST_USER_REPLY_MASK | VHOST_USER_VERSION;
> +    vmsg->size  = sizeof(vmsg->payload.u64);
> +    vmsg->payload.u64 = VHOST_MEMORY_MAX_NREGIONS;
> +    vmsg->fd_num = 0;
> +
> +    if (!vu_message_write(dev, dev->sock, vmsg)) {
> +        vu_panic(dev, "Failed to send max ram slots: %s\n",
> strerror(errno));
> +    }
> +
> +    DPRINT("u64: 0x%016"PRIx64"\n", (uint64_t) VHOST_MEMORY_MAX_NREGIONS);
> +
> +    return false;
> +}
> +
>  static bool
>  vu_process_message(VuDev *dev, VhostUserMsg *vmsg)
>  {
> @@ -1649,6 +1666,8 @@ vu_process_message(VuDev *dev, VhostUserMsg *vmsg)
>          return vu_set_inflight_fd(dev, vmsg);
>      case VHOST_USER_VRING_KICK:
>          return vu_handle_vring_kick(dev, vmsg);
> +    case VHOST_USER_GET_MAX_MEM_SLOTS:
> +        return vu_handle_get_max_memslots(dev, vmsg);
>      default:
>          vmsg_close_fds(vmsg);
>          vu_panic(dev, "Unhandled request: %d", vmsg->request);
> diff --git a/contrib/libvhost-user/libvhost-user.h
> b/contrib/libvhost-user/libvhost-user.h
> index f30394f..88ef40d 100644
> --- a/contrib/libvhost-user/libvhost-user.h
> +++ b/contrib/libvhost-user/libvhost-user.h
> @@ -97,6 +97,7 @@ typedef enum VhostUserRequest {
>      VHOST_USER_SET_INFLIGHT_FD = 32,
>      VHOST_USER_GPU_SET_SOCKET = 33,
>      VHOST_USER_VRING_KICK = 35,
> +    VHOST_USER_GET_MAX_MEM_SLOTS = 36,
>      VHOST_USER_MAX
>  } VhostUserRequest;
>
> --
> 1.8.3.1
>
>

-- 
Marc-André Lureau