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From: Eugenio Perez Martin <eperezma@redhat.com>
Date: Wed, 3 Apr 2024 08:07:53 +0200
Message-ID: <CAJaqyWd+MsOc=ac_Ns=L0xtQ9iTX-0_sbREokRQnnjr_aHF6fQ@mail.gmail.com>
Subject: Re: [PATCH] vhost-vdpa: change ioctl # for VDPA_GET_VRING_SIZE
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: linux-kernel@vger.kernel.org, Arnaldo Carvalho de Melo <acme@kernel.org>, 
	Namhyung Kim <namhyung@kernel.org>, Zhu Lingshan <lingshan.zhu@intel.com>, 
	Jason Wang <jasowang@redhat.com>, kvm@vger.kernel.org, virtualization@lists.linux.dev, 
	netdev@vger.kernel.org, Adrian Hunter <adrian.hunter@intel.com>, 
	Ian Rogers <irogers@google.com>, Jiri Olsa <jolsa@kernel.org>, 
	Kan Liang <kan.liang@linux.intel.com>
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On Tue, Apr 2, 2024 at 11:21=E2=80=AFPM Michael S. Tsirkin <mst@redhat.com>=
 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: Eugenio P=C3=A9rez <eperezma@redhat.com>

> ---
>
> 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
> --
> MST
>