Chang S. Bae d31d50b35d x86/microcode/intel: Remove unnecessary cache writeback and invalidation
commit 9a819753b0209c6edebdea447a1aa53e8c697653 upstream

Currently, an unconditional cache flush is performed during every
microcode update. Although the original changelog did not mention
a specific erratum, this measure was primarily intended to address
a specific microcode bug, the load of which has already been blocked by
is_blacklisted(). Therefore, this cache flush is no longer necessary.

Additionally, the side effects of doing this have been overlooked. It
increases CPU rendezvous time during late loading, where the cache flush
takes between 1x to 3.5x longer than the actual microcode update.

Remove native_wbinvd() and update the erratum name to align with the
latest errata documentation, document ID 334163 Version 022US.

  [ bp: Zap the flaky documentation URL. ]

Fixes: 91df9fdf51 ("x86/microcode/intel: Writeback and invalidate caches before updating microcode")
Reported-by: Yan Hua Wu <yanhua1.wu@intel.com>
Reported-by: William Xie <william.xie@intel.com>
Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Ashok Raj <ashok.raj@intel.com>
Tested-by: Yan Hua Wu <yanhua1.wu@intel.com>
Link: https://lore.kernel.org/r/20241001161042.465584-2-chang.seok.bae@intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-03-07 16:45:55 +01:00
2022-09-28 09:02:20 +02:00
2025-02-27 04:10:54 -08:00

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.
Description
No description provided
Readme 7.9 GiB
Languages
C 97.7%
Assembly 1.6%
Makefile 0.3%
Perl 0.1%