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41f4767000
While restricting access,
a7e1f67ed2 ("x86/msr: Filter MSR writes")
also added warning and started tainting the kernel.
But the warning message never mentioned tainting. Moreover, this uses the
"CPU_OUT_OF_SPEC" flag which is not clearly related to MSRs: that flag is
overloaded by several, fairly different situations, including some much
scarier ones.
So, without an expert around (thank you Dave Hansen), it would have been
practically impossible to root cause the tainting from just the log file at
hand. So it would be prudent to explicitly mention in the logs when the
tainting happens so that debugging crashes can be made easier.
Fix this by simply appending the CPU_OUT_OF_SPEC flag to the warning message.
This readability issue happened when staring at logs involving the Intel
Memory Latency Checker (among many other things going on in that log). The MLC
disables hardware prefetch.
[ bp: Massage and extend commit message. ]
Signed-off-by: Marc Herbert <marc.herbert@linux.intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20251101-tainted-msr-v1-1-e00658ba04d4@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 reStructuredText 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.