Re: [PATCH fyi 1/1] perf trace beauty: Sync linux/vhost.h with the kernel sources

[Namhyung Kim]

On Thu, Mar 21, 2024 at 1:41 PM Arnaldo Carvalho de Melo
<acme@xxxxxxxxxx> wrote:
>
> tldr; Just FYI, I'm carrying this on the perf tools tree.

Have you applied this to perf-tools-next?

>
> Full explanation:
>
> There used to be no copies, with tools/ code using kernel headers
> directly. From time to time tools/perf/ broke due to legitimate kernel
> hacking. At some point Linus complained about such direct usage. Then we
> adopted the current model.
>
> The way these headers are used in perf are not restricted to just
> including them to compile something.
>
> There are sometimes used in scripts that convert defines into string
> tables, etc, so some change may break one of these scripts, or new MSRs
> may use some different #define pattern, etc.
>
> E.g.:
>
>   $ ls -1 tools/perf/trace/beauty/*.sh | head -5
>   tools/perf/trace/beauty/arch_errno_names.sh
>   tools/perf/trace/beauty/drm_ioctl.sh
>   tools/perf/trace/beauty/fadvise.sh
>   tools/perf/trace/beauty/fsconfig.sh
>   tools/perf/trace/beauty/fsmount.sh
>   $
>   $ tools/perf/trace/beauty/fadvise.sh
>   static const char *fadvise_advices[] = {
>         [0] = "NORMAL",
>         [1] = "RANDOM",
>         [2] = "SEQUENTIAL",
>         [3] = "WILLNEED",
>         [4] = "DONTNEED",
>         [5] = "NOREUSE",
>   };
>   $
>
> The tools/perf/check-headers.sh script, part of the tools/ build
> process, points out changes in the original files.
>
> So its important not to touch the copies in tools/ when doing changes in
> the original kernel headers, that will be done later, when
> check-headers.sh inform about the change to the perf tools hackers.
>
> To get the changes in:
>
>   1496c47065f9f841 ("vhost-vdpa: uapi to support reporting per vq size")
>
> To pick up these changes and support them:
>
>   $ tools/perf/trace/beauty/vhost_virtio_ioctl.sh > before
>   $ cp include/uapi/linux/vhost.h tools/perf/trace/beauty/include/uapi/linux/vhost.h
>   $ tools/perf/trace/beauty/vhost_virtio_ioctl.sh > after
>   $ diff -u before after
>   --- before    2024-03-21 17:33:58.878173388 -0300
>   +++ after     2024-03-21 17:34:07.687563333 -0300
>   @@ -49,6 +49,7 @@
>         [0x7B] = "VDPA_GET_VRING_GROUP",
>         [0x7F] = "VDPA_GET_VRING_DESC_GROUP",
>         [0x80] = "VDPA_GET_VQS_COUNT",
>   +     [0x80] = "VDPA_GET_VRING_SIZE",

This gives me a build error:

  CC      trace/beauty/ioctl.o
In file included from trace/beauty/ioctl.c:93:
linux/tools/perf/trace/beauty/generated/ioctl/vhost_virtio_ioctl_array.c:
   In function ‘ioctl__scnprintf_vhost_virtio_cmd’:
linux/tools/perf/trace/beauty/generated/ioctl/vhost_virtio_ioctl_array.c:53:18:
   error: initialized field overwritten [-Werror=override-init]
   53 |         [0x80] = "VDPA_GET_VRING_SIZE",
      |                  ^~~~~~~~~~~~~~~~~~~~~
linux/tools/perf/trace/beauty/generated/ioctl/vhost_virtio_ioctl_array.c:53:18:
   note: (near initialization for ‘vhost_virtio_ioctl_read_cmds[128]’)

Because there are two entries for 0x80 now.

Is it ok for vhost to have the same number for VQS_COUNT
and VRING_SIZE?

Thanks,
Namhyung


>         [0x81] = "VDPA_GET_GROUP_NUM",
>         [0x8] = "NEW_WORKER",
>    };
>   $
>
> For instance, see how those 'cmd' ioctl arguments get translated, now
> VDPA_GET_VRING_SIZE will be as well.
>
>   # perf trace -a -e ioctl --max-events=10
>        0.000 ( 0.011 ms): pipewire/2261 ioctl(fd: 60, cmd: SNDRV_PCM_HWSYNC, arg: 0x1)                   = 0
>       21.353 ( 0.014 ms): pipewire/2261 ioctl(fd: 60, cmd: SNDRV_PCM_HWSYNC, arg: 0x1)                   = 0
>       25.766 ( 0.014 ms): gnome-shell/2196 ioctl(fd: 14, cmd: DRM_I915_IRQ_WAIT, arg: 0x7ffe4a22c740)    = 0
>       25.845 ( 0.034 ms): gnome-shel:cs0/2212 ioctl(fd: 14, cmd: DRM_I915_IRQ_EMIT, arg: 0x7fd43915dc70) = 0
>       25.916 ( 0.011 ms): gnome-shell/2196 ioctl(fd: 9, cmd: DRM_MODE_ADDFB2, arg: 0x7ffe4a22c8a0)       = 0
>       25.941 ( 0.025 ms): gnome-shell/2196 ioctl(fd: 9, cmd: DRM_MODE_ATOMIC, arg: 0x7ffe4a22c840)       = 0
>       32.915 ( 0.009 ms): gnome-shell/2196 ioctl(fd: 9, cmd: DRM_MODE_RMFB, arg: 0x7ffe4a22cf9c)         = 0
>       42.522 ( 0.013 ms): gnome-shell/2196 ioctl(fd: 14, cmd: DRM_I915_IRQ_WAIT, arg: 0x7ffe4a22c740)    = 0
>       42.579 ( 0.031 ms): gnome-shel:cs0/2212 ioctl(fd: 14, cmd: DRM_I915_IRQ_EMIT, arg: 0x7fd43915dc70) = 0
>       42.644 ( 0.010 ms): gnome-shell/2196 ioctl(fd: 9, cmd: DRM_MODE_ADDFB2, arg: 0x7ffe4a22c8a0)       = 0
>   #
>
> Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
> Cc: Ian Rogers <irogers@xxxxxxxxxx>
> Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
> Cc: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
> Cc: Michael S. Tsirkin <mst@xxxxxxxxxx>
> Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
> Cc: Zhu Lingshan <lingshan.zhu@xxxxxxxxx>
> Link: https://lore.kernel.org/lkml/
> Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
> ---
>  tools/perf/trace/beauty/include/uapi/linux/vhost.h | 7 +++++++
>  1 file changed, 7 insertions(+)
>
> diff --git a/tools/perf/trace/beauty/include/uapi/linux/vhost.h b/tools/perf/trace/beauty/include/uapi/linux/vhost.h
> index 649560c685f13b73..bea6973906134656 100644
> --- a/tools/perf/trace/beauty/include/uapi/linux/vhost.h
> +++ b/tools/perf/trace/beauty/include/uapi/linux/vhost.h
> @@ -227,4 +227,11 @@
>   */
>  #define VHOST_VDPA_GET_VRING_DESC_GROUP        _IOWR(VHOST_VIRTIO, 0x7F,       \
>                                               struct vhost_vring_state)
> +
> +/* 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,       \
> +                                             struct vhost_vring_state)
>  #endif
> --
> 2.44.0
>