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80a5ce116f
It might be possible that different CPUs have different CPU metrics on a
platform. In this case, writing the GLOBAL_CTRL_EN_PERF_METRICS bit to
the GLOBAL_CTRL register of a CPU, which doesn't support the TopDown
perf metrics feature, causes MSR access error.
Current TopDown perf metrics feature is enumerated using the boot CPU's
PERF_CAPABILITIES MSR. The MSR only indicates the boot CPU supports this
feature.
Check the PERF_CAPABILITIES MSR for each CPU. If any CPU doesn't support
the perf metrics feature, disable the feature globally.
Fixes: 59a854e2f3 ("perf/x86/intel: Support TopDown metrics on Ice Lake")
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20201001211711.25708-1-kan.liang@linux.intel.com
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.