perf trace beautify ioctl: Beautify vhost virtio ioctl's 'cmd' arg

perf trace beautify ioctl: Beautify vhost virtio ioctl's 'cmd' arg

Also trying a new approach, using a copy of uapi/linux/vhost.h we auto
generate the string tables, then include it in the ioctl cmd beautifier.

This way either the KVM developers will add the new commands to the
tools/ copy, like is happening with other areas of tools/include/ (bpf.h
comes to mind), or we'll be notified when building perf that our copy
drifted.

E.g., doing syswide tracing grepping for the newly beautified VHOST
ioctls:

  # perf trace -e ioctl 2>&1 | grep VHOST
  3873.064 ( 0.099 ms): qemu-system-x8/21238 ioctl(fd: 27</dev/vhost-net>, cmd: VHOST_NET_SET_BACKEND, arg: 0x7fff053dffe0) = 0
  3873.168 ( 0.019 ms): qemu-system-x8/21238 ioctl(fd: 27</dev/vhost-net>, cmd: VHOST_NET_SET_BACKEND, arg: 0x7fff053dffe0) = 0
  3873.226 ( 0.006 ms): qemu-system-x8/21238 ioctl(fd: 27</dev/vhost-net>, cmd: VHOST_GET_VRING_BASE, arg: 0x7fff053dff60) = 0
  3873.244 ( 0.002 ms): qemu-system-x8/21238 ioctl(fd: 27</dev/vhost-net>, cmd: VHOST_GET_VRING_BASE, arg: 0x7fff053dff60) = 0
  3873.817 ( 0.014 ms): qemu-system-x8/21238 ioctl(fd: 27</dev/vhost-net>, cmd: VHOST_SET_VRING_CALL, arg: 0x7fff053dff20) = 0
  3873.838 ( 0.004 ms): qemu-system-x8/21238 ioctl(fd: 27</dev/vhost-net>, cmd: VHOST_SET_VRING_CALL, arg: 0x7fff053dff20) = 0
  4701.372 ( 0.006 ms): qemu-system-x8/21238 ioctl(fd: 27</dev/vhost-net>, cmd: VHOST_SET_VRING_CALL, arg: 0x7fff053dfe20) = 0
  4701.417 ( 0.007 ms): qemu-system-x8/21238 ioctl(fd: 27</dev/vhost-net>, cmd: VHOST_SET_VRING_CALL, arg: 0x7fff053dfe20) = 0
  4701.563 ( 0.004 ms): qemu-system-x8/21238 ioctl(fd: 27</dev/vhost-net>, cmd: VHOST_SET_FEATURES, arg: 0x7fff053dfe88) = 0
  4701.571 ( 0.028 ms): qemu-system-x8/21238 ioctl(fd: 27</dev/vhost-net>, cmd: VHOST_SET_MEM_TABLE, arg: 0x563c7c906870) = 0
  4701.604 ( 0.003 ms): qemu-system-x8/21238 ioctl(fd: 27</dev/vhost-net>, cmd: VHOST_SET_VRING_NUM, arg: 0x7fff053dff00) = 0
  4701.609 ( 0.002 ms): qemu-system-x8/21238 ioctl(fd: 27</dev/vhost-net>, cmd: VHOST_SET_VRING_BASE, arg: 0x7fff053dff00) = 0
  4701.615 ( 0.002 ms): qemu-system-x8/21238 ioctl(fd: 27</dev/vhost-net>, cmd: VHOST_SET_VRING_ADDR, arg: 0x7fff053dfe70) = 0
  4701.619 ( 0.008 ms): qemu-system-x8/21238 ioctl(fd: 27</dev/vhost-net>, cmd: VHOST_SET_VRING_KICK, arg: 0x7fff053dfef0) = 0
  4701.634 ( 0.004 ms): qemu-system-x8/21238 ioctl(fd: 27</dev/vhost-net>, cmd: VHOST_SET_VRING_NUM, arg: 0x7fff053dff00) = 0
  4701.640 ( 0.002 ms): qemu-system-x8/21238 ioctl(fd: 27</dev/vhost-net>, cmd: VHOST_SET_VRING_BASE, arg: 0x7fff053dff00) = 0
  4701.644 ( 0.002 ms): qemu-system-x8/21238 ioctl(fd: 27</dev/vhost-net>, cmd: VHOST_SET_VRING_ADDR, arg: 0x7fff053dfe70) = 0
  4701.648 ( 0.009 ms): qemu-system-x8/21238 ioctl(fd: 27</dev/vhost-net>, cmd: VHOST_SET_VRING_KICK, arg: 0x7fff053dfef0) = 0
  4701.665 ( 0.005 ms): qemu-system-x8/21238 ioctl(fd: 27</dev/vhost-net>, cmd: VHOST_NET_SET_BACKEND, arg: 0x7fff053dff80) = 0
  4701.672 ( 0.004 ms): qemu-system-x8/21238 ioctl(fd: 27</dev/vhost-net>, cmd: VHOST_NET_SET_BACKEND, arg: 0x7fff053dff80) = 0
^C

 '-e ioctl' uses tracepoint filters, in time this will be replaces by
eBPF filters hooked at the syscall tracepoints and that "grep VHOST"
will also be done with eBPF, right at the kernel, to reduce overhead.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-2gthnhpliunvakywjterrzz3@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>