linux-kernel - [PATCH FYI 1/1] tools include UAPI: Sync linux/vhost.h with the kernel sources

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Message-ID: <Yv6Kb4OESuNJuH6X@kernel.org>
Date:   Thu, 18 Aug 2022 15:52:31 -0300
From:   Arnaldo Carvalho de Melo <acme@...nel.org>
To:     linux-kernel@...r.kernel.org
Cc:     Adrian Hunter <adrian.hunter@...el.com>,
        Eugenio Pérez <eperezma@...hat.com>,
        Ian Rogers <irogers@...gle.com>, Jiri Olsa <jolsa@...nel.org>,
        "Michael S. Tsirkin" <mst@...hat.com>,
        Namhyung Kim <namhyung@...nel.org>
Subject: [PATCH FYI 1/1] tools include UAPI: Sync linux/vhost.h with the
 kernel sources

tldr; Just FYI, I'm carrying this on the perf tools tree.

- Arnaldo

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:

  f345a0143b4dd1cf ("vhost-vdpa: uAPI to suspend the device")

Silencing this perf build warning:

  Warning: Kernel ABI header at 'tools/include/uapi/linux/vhost.h' differs from latest version at 'include/uapi/linux/vhost.h'
  diff -u tools/include/uapi/linux/vhost.h include/uapi/linux/vhost.h

To pick up these changes and support them:

  $ tools/perf/trace/beauty/vhost_virtio_ioctl.sh > before
  $ cp include/uapi/linux/vhost.h tools/include/uapi/linux/vhost.h
  $ tools/perf/trace/beauty/vhost_virtio_ioctl.sh > after
  $ diff -u before after
  --- before	2022-08-18 09:46:12.355958316 -0300
  +++ after	2022-08-18 09:46:19.701182822 -0300
  @@ -29,6 +29,7 @@
   	[0x75] = "VDPA_SET_VRING_ENABLE",
   	[0x77] = "VDPA_SET_CONFIG_CALL",
   	[0x7C] = "VDPA_SET_GROUP_ASID",
  +	[0x7D] = "VDPA_SUSPEND",
   };
   = {
   	[0x00] = "GET_FEATURES",
  $

For instance, see how those 'cmd' ioctl arguments get translated, now
VDPA_SUSPEND 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@...el.com>
Cc: Eugenio Pérez <eperezma@...hat.com>
Cc: Ian Rogers <irogers@...gle.com>
Cc: Jiri Olsa <jolsa@...nel.org>
Cc: Michael S. Tsirkin <mst@...hat.com>
Cc: Namhyung Kim <namhyung@...nel.org>
Link: https://lore.kernel.org/lkml/
Signed-off-by: Arnaldo Carvalho de Melo <acme@...hat.com>
---
 tools/include/uapi/linux/vhost.h | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/tools/include/uapi/linux/vhost.h b/tools/include/uapi/linux/vhost.h
index cab645d4a6455564..f9f115a7c75b8a30 100644
--- a/tools/include/uapi/linux/vhost.h
+++ b/tools/include/uapi/linux/vhost.h
@@ -171,4 +171,13 @@
 #define VHOST_VDPA_SET_GROUP_ASID	_IOW(VHOST_VIRTIO, 0x7C, \
 					     struct vhost_vring_state)
 
+/* Suspend a device so it does not process virtqueue requests anymore
+ *
+ * After the return of ioctl the device must preserve all the necessary state
+ * (the virtqueue vring base plus the possible device specific states) that is
+ * required for restoring in the future. The device must not change its
+ * configuration after that point.
+ */
+#define VHOST_VDPA_SUSPEND		_IO(VHOST_VIRTIO, 0x7D)
+
 #endif
-- 
2.37.1