linux-kernel - [PATCH v1 00/12] x86/mce: Correct the noinstr annotation

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Message-Id: <20211208111343.8130-1-bp@alien8.de>
Date:   Wed,  8 Dec 2021 12:13:31 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     Tony Luck <tony.luck@...el.com>
Cc:     X86 ML <x86@...nel.org>, LKML <linux-kernel@...r.kernel.org>
Subject: [PATCH v1 00/12] x86/mce: Correct the noinstr annotation

From: Borislav Petkov <bp@...e.de>

Hi folks,

here's v1 with the instrumentation "sandwiching" documented, as
requested by peterz.

Tony, I'd appreciate making sure nothing in them breaks your injection
workflows before I queue them. And it shouldn't but... :-)

Thx.

Changelog:
==========

here's a first preliminary (it is based on some random 5.16-rc0 commit
and is tested only in qemu) of the series which correct all the noinstr
annotation of the #MC handler.

Since it calls a bunch of external facilities, the strategy is to mark
mce-specific functions called by the #MC handler as noinstr and when
they "call out" so to speak, to do a begin/end sandwich around that
call.

Please have a look and let me know if it looks ok-ish.

Further testing will happen after -rc1 releases, thus the "v0" version
here.

Thx.

Borislav Petkov (12):
  x86/mce: Do not use memset to clear the banks bitmaps
  x86/mce: Remove function-local cpus variables
  x86/mce: Use mce_rdmsrl() in severity checking code
  x86/mce: Remove noinstr annotation from mce_setup()
  x86/mce: Allow instrumentation during task work queueing
  x86/mce: Prevent severity computation from being instrumented
  x86/mce: Mark mce_panic() noinstr
  x86/mce: Mark mce_end() noinstr
  x86/mce: Mark mce_read_aux() noinstr
  x86/mce: Move the tainting outside of the noinstr region
  x86/mce: Mark mce_timed_out() noinstr
  x86/mce: Mark mce_start() noinstr

 arch/x86/kernel/cpu/mce/core.c     | 128 +++++++++++++++++++++--------
 arch/x86/kernel/cpu/mce/internal.h |   2 +
 arch/x86/kernel/cpu/mce/severity.c |  38 +++++----
 3 files changed, 119 insertions(+), 49 deletions(-)

-- 
2.29.2