Arnaldo Carvalho de Melo e652ab64e5 tools arch x86: Sync the msr-index.h copy with the kernel sources
To pick up the changes in:

  89aa94b4a2 ("x86/msr: Add AMD CPPC MSR definitions")

Addressing these tools/perf build warnings:

    diff -u tools/arch/x86/include/asm/msr-index.h arch/x86/include/asm/msr-index.h
    Warning: Kernel ABI header at 'tools/arch/x86/include/asm/msr-index.h' differs from latest version at 'arch/x86/include/asm/msr-index.h'

That makes the beautification scripts to pick some new entries:

  $ tools/perf/trace/beauty/tracepoints/x86_msr.sh > before
  $ cp arch/x86/include/asm/msr-index.h tools/arch/x86/include/asm/msr-index.h
  $ tools/perf/trace/beauty/tracepoints/x86_msr.sh > after
  $ diff -u before after
  --- before	2022-01-13 10:59:51.743416890 -0300
  +++ after	2022-01-13 11:00:00.776644178 -0300
  @@ -303,6 +303,11 @@
 	  [0xc0010299 - x86_AMD_V_KVM_MSRs_offset] = "AMD_RAPL_POWER_UNIT",
 	  [0xc001029a - x86_AMD_V_KVM_MSRs_offset] = "AMD_CORE_ENERGY_STATUS",
 	  [0xc001029b - x86_AMD_V_KVM_MSRs_offset] = "AMD_PKG_ENERGY_STATUS",
  +       [0xc00102b0 - x86_AMD_V_KVM_MSRs_offset] = "AMD_CPPC_CAP1",
  +       [0xc00102b1 - x86_AMD_V_KVM_MSRs_offset] = "AMD_CPPC_ENABLE",
  +       [0xc00102b2 - x86_AMD_V_KVM_MSRs_offset] = "AMD_CPPC_CAP2",
  +       [0xc00102b3 - x86_AMD_V_KVM_MSRs_offset] = "AMD_CPPC_REQ",
  +       [0xc00102b4 - x86_AMD_V_KVM_MSRs_offset] = "AMD_CPPC_STATUS",
 	  [0xc00102f0 - x86_AMD_V_KVM_MSRs_offset] = "AMD_PPIN_CTL",
 	  [0xc00102f1 - x86_AMD_V_KVM_MSRs_offset] = "AMD_PPIN",
   };
  $

And this gets rebuilt:

  CC       /tmp/build/perf/trace/beauty/tracepoints/x86_msr.o
  INSTALL  trace_plugins
  LD       /tmp/build/perf/trace/beauty/tracepoints/perf-in.o
  LD       /tmp/build/perf/trace/beauty/perf-in.o
  LD       /tmp/build/perf/perf-in.o
  LINK     /tmp/build/perf/perf

Now one can trace systemwide asking to see backtraces to where those
MSRs are being read/written with:

  # perf trace -e msr:*_msr/max-stack=32/ --filter="msr>=AMD_CPPC_CAP1 && msr<=AMD_CPPC_STATUS"
  ^C#

If we use -v (verbose mode) we can see what it does behind the scenes:

  # perf trace -v -e msr:*_msr/max-stack=32/ --filter="msr>=AMD_CPPC_CAP1 && msr<=AMD_CPPC_STATUS"
  <SNIP>
  New filter for msr:read_msr: (msr>=0xc00102b0 && msr<=0xc00102b4) && (common_pid != 2612102 && common_pid != 3841)
  New filter for msr:write_msr: (msr>=0xc00102b0 && msr<=0xc00102b4) && (common_pid != 2612102 && common_pid != 3841)
  <SNIP>
  ^C#

Example with a frequent msr:

  # perf trace -v -e msr:*_msr/max-stack=32/ --filter="msr==IA32_SPEC_CTRL" --max-events 2
  Using CPUID AuthenticAMD-25-21-0
  0x48
  New filter for msr:read_msr: (msr==0x48) && (common_pid != 2612129 && common_pid != 3841)
  0x48
  New filter for msr:write_msr: (msr==0x48) && (common_pid != 2612129 && common_pid != 3841)
  mmap size 528384B
  Looking at the vmlinux_path (8 entries long)
  symsrc__init: build id mismatch for vmlinux.
  Using /proc/kcore for kernel data
  Using /proc/kallsyms for symbols
       0.000 Timer/2525383 msr:write_msr(msr: IA32_SPEC_CTRL, val: 6)
                                         do_trace_write_msr ([kernel.kallsyms])
                                         do_trace_write_msr ([kernel.kallsyms])
                                         __switch_to_xtra ([kernel.kallsyms])
                                         __switch_to ([kernel.kallsyms])
                                         __schedule ([kernel.kallsyms])
                                         schedule ([kernel.kallsyms])
                                         futex_wait_queue_me ([kernel.kallsyms])
                                         futex_wait ([kernel.kallsyms])
                                         do_futex ([kernel.kallsyms])
                                         __x64_sys_futex ([kernel.kallsyms])
                                         do_syscall_64 ([kernel.kallsyms])
                                         entry_SYSCALL_64_after_hwframe ([kernel.kallsyms])
                                         __futex_abstimed_wait_common64 (/usr/lib64/libpthread-2.33.so)
       0.030 :0/0 msr:write_msr(msr: IA32_SPEC_CTRL, val: 2)
                                         do_trace_write_msr ([kernel.kallsyms])
                                         do_trace_write_msr ([kernel.kallsyms])
                                         __switch_to_xtra ([kernel.kallsyms])
                                         __switch_to ([kernel.kallsyms])
                                         __schedule ([kernel.kallsyms])
                                         schedule_idle ([kernel.kallsyms])
                                         do_idle ([kernel.kallsyms])
                                         cpu_startup_entry ([kernel.kallsyms])
                                         secondary_startup_64_no_verify ([kernel.kallsyms])
  #

Acked-by: Huang Rui <ray.huang@amd.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/all/YeA2PAvHV+uHRhLj@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2022-01-14 11:34:32 -03:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
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