[<prev] [next>] [thread-next>] [day] [month] [year] [list]
Message-Id: <20230113172920.113612-1-ashok.raj@intel.com>
Date: Fri, 13 Jan 2023 09:29:15 -0800
From: Ashok Raj <ashok.raj@...el.com>
To: Borislav Petkov <bp@...en8.de>,
Thomas Gleixner <tglx@...utronix.de>
Cc: Ashok Raj <ashok.raj@...el.com>,
LKML <linux-kernel@...r.kernel.org>, x86 <x86@...nel.org>,
Ingo Molnar <mingo@...nel.org>,
Tony Luck <tony.luck@...el.com>,
Dave Hansen <dave.hansen@...el.com>,
Alison Schofield <alison.schofield@...el.com>,
Reinette Chatre <reinette.chatre@...el.com>,
Tom Lendacky <thomas.lendacky@....com>,
Stefan Talpalaru <stefantalpalaru@...oo.com>,
David Woodhouse <dwmw2@...radead.org>,
Benjamin Herrenschmidt <benh@...nel.crashing.org>,
Jonathan Corbet <corbet@....net>,
"Rafael J . Wysocki" <rafael@...nel.org>,
Peter Zilstra <peterz@...radead.org>,
Andy Lutomirski <luto@...nel.org>,
Andrew Cooper <Andrew.Cooper3@...rix.com>
Subject: [PATCH v1 Part2 0/5] Declare safe late loadable microcode
Hi Boris & Thomas,
Attached is a series that adds support for microcode to declare a minimum
revision number that is safe for late loading.
Late loading was disabled[1] in 5.19 due to lack of an ability to declare
when a microcode is safe for late loading.
This series is inspired by recommendations from Thomas [2].
This series is part2 and applies on top of that cleanup series part1[3].
- Move where the warning and tainting is done to the same function. It
helps when later patches enable late loading, to issue the warning only
when the vendor doesn't support a mechanism for declaring a microcode
for safe late loading.
- Add meta-data for Intel microcode to specify a minimum revision that the
CPU must be on before attempting to load this microcode.
- Extend this as a generic mechanism to allow the common infrastructure to
permit late loading.
- Some CPUs required a wbinvd() to be issued before attempting to load a
microcode. These were later addressed via microcode patches. Now there
exists a mechanism to declare a minimum revision, those flushes aren't
required any longer.
- Provide a mechanism to override minrev as a way to bypass during the
transition. It is recommended to always use early loading, especially if
one is moving to a newer kernel. This is a chicken bit option :) and
completely optional.
[1] https://lore.kernel.org/lkml/20220524185324.28395-3-bp@alien8.de/
[2] https://lore.kernel.org/linux-kernel/alpine.DEB.2.21.1909062237580.1902@nanos.tec.linutronix.de/
[3] https://lore.kernel.org/lkml/20230109153555.4986-1-ashok.raj@intel.com/
Cheers,
Ashok
Cc: LKML <linux-kernel@...r.kernel.org>
Cc: x86 <x86@...nel.org>
Cc: Ingo Molnar <mingo@...nel.org>
Cc: Tony Luck <tony.luck@...el.com>
Cc: Dave Hansen <dave.hansen@...el.com>
Cc: Alison Schofield <alison.schofield@...el.com>
Cc: Reinette Chatre <reinette.chatre@...el.com>
Cc: Thomas Gleixner (Intel) <tglx@...utronix.de>
Cc: Tom Lendacky <thomas.lendacky@....com>
Cc: Stefan Talpalaru <stefantalpalaru@...oo.com>
Cc: David Woodhouse <dwmw2@...radead.org>
Cc: Benjamin Herrenschmidt <benh@...nel.crashing.org>
Cc: Jonathan Corbet <corbet@....net>
Cc: Rafael J. Wysocki <rafael@...nel.org>
Cc: Peter Zilstra (Intel) <peterz@...radead.org>
Cc: Andy Lutomirski <luto@...nel.org>
Cc: Andrew Cooper <Andrew.Cooper3@...rix.com>
Ashok Raj (5):
x86/microcode: Move late load warning to the same function that taints
kernel
x86/microcode/intel: Add minimum required revision to microcode header
x86/microcode: Add a generic mechanism to declare support for minrev
x86/microcode/intel: Drop wbinvd() from microcode loading
x86/microcode: Provide an option to override minrev enforcement
arch/x86/include/asm/microcode.h | 4 ++
arch/x86/include/asm/microcode_intel.h | 3 +-
arch/x86/kernel/cpu/microcode/core.c | 36 ++++++++++++++---
arch/x86/kernel/cpu/microcode/intel.c | 55 ++++++++++++++++++++------
arch/x86/Kconfig | 7 ++--
5 files changed, 83 insertions(+), 22 deletions(-)
--
2.34.1
Powered by blists - more mailing lists