Re: [PATCH] vhost-vdpa: change ioctl # for VDPA_GET_VRING_SIZE

["Zhu, Lingshan" <lingshan.zhu@intel.com>]

On 4/3/2024 5:21 AM, Michael S. Tsirkin wrote:
> VDPA_GET_VRING_SIZE by mistake uses the already occupied
> ioctl # 0x80 and we never noticed - it happens to work
> because the direction and size are different, but confuses
> tools such as perf which like to look at just the number,
> and breaks the extra robustness of the ioctl numbering macros.
>
> To fix, sort the entries and renumber the ioctl - not too late
> since it wasn't in any released kernels yet.
>
> Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
> Reported-by: Namhyung Kim <namhyung@kernel.org>
> Fixes: 1496c47065f9 ("vhost-vdpa: uapi to support reporting per vq size")
> Cc: "Zhu Lingshan" <lingshan.zhu@intel.com>
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

Reviewed-by: Zhu Lingshan <lingshan.zhu@intel.com>

Thanks for the fix and sorry for the mess, I should read the whole header file to check whether
the number is available.

> ---
>
> Build tested only - userspace patches using this will have to adjust.
> I will merge this in a week or so unless I hear otherwise,
> and afterwards perf can update there header.
>
>   include/uapi/linux/vhost.h | 15 ++++++++-------
>   1 file changed, 8 insertions(+), 7 deletions(-)
>
> diff --git a/include/uapi/linux/vhost.h b/include/uapi/linux/vhost.h
> index bea697390613..b95dd84eef2d 100644
> --- a/include/uapi/linux/vhost.h
> +++ b/include/uapi/linux/vhost.h
> @@ -179,12 +179,6 @@
>   /* Get the config size */
>   #define VHOST_VDPA_GET_CONFIG_SIZE	_IOR(VHOST_VIRTIO, 0x79, __u32)
>   
> -/* Get the count of all virtqueues */
> -#define VHOST_VDPA_GET_VQS_COUNT	_IOR(VHOST_VIRTIO, 0x80, __u32)
> -
> -/* Get the number of virtqueue groups. */
> -#define VHOST_VDPA_GET_GROUP_NUM	_IOR(VHOST_VIRTIO, 0x81, __u32)
> -
>   /* Get the number of address spaces. */
>   #define VHOST_VDPA_GET_AS_NUM		_IOR(VHOST_VIRTIO, 0x7A, unsigned int)
>   
> @@ -228,10 +222,17 @@
>   #define VHOST_VDPA_GET_VRING_DESC_GROUP	_IOWR(VHOST_VIRTIO, 0x7F,	\
>   					      struct vhost_vring_state)
>   
> +
> +/* Get the count of all virtqueues */
> +#define VHOST_VDPA_GET_VQS_COUNT	_IOR(VHOST_VIRTIO, 0x80, __u32)
> +
> +/* Get the number of virtqueue groups. */
> +#define VHOST_VDPA_GET_GROUP_NUM	_IOR(VHOST_VIRTIO, 0x81, __u32)
> +
>   /* Get the queue size of a specific virtqueue.
>    * userspace set the vring index in vhost_vring_state.index
>    * kernel set the queue size in vhost_vring_state.num
>    */
> -#define VHOST_VDPA_GET_VRING_SIZE	_IOWR(VHOST_VIRTIO, 0x80,	\
> +#define VHOST_VDPA_GET_VRING_SIZE	_IOWR(VHOST_VIRTIO, 0x82,	\
>   					      struct vhost_vring_state)
>   #endif