Messages in this thread | | | From | Ashok Raj <> | Subject | [Patch v3 Part2 0/9] x86/microcode: Declare microcode safe for late loading | Date | Mon, 30 Jan 2023 13:39:46 -0800 |
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Hi Boris,
Here is v3 of part2. v1 Part2 is here[1] These address feedback from Thomas here [2] posted as "Part2 v2[cleanup]"
Thanks Thomas for the feedback, and Tony for fixes to my commit logs adding more clarity!
This series should apply on top of tip/x86/microcode.
Please help with review and apply.
Patch 1-4: Cleanup patches that were in response to comments from Thomas[2].
Patch 5: Preparatory patch to keep warning and taint in same function. Patch 6: Add minimum revision ID for Intel microcode Patch 7: Add a generic mechanism to declare safe late loading. Patch 8: Drop the unneeded wbinvd() after the minimum rev update Patch 9: Optional - Allows testing with override minrev.
Tests Done:
1. For values other than 1 to reload file, will not report an error. For e.g.
echo 2 > reload bash: echo: write error: Invalid argument
2. In cases where there is no file OR no new update found, echo 1 will not report an error
echo 1 > reload
3. When trying to load a file with minrev=0, there will be a log in dmesg and will also return -EINVAL in response to the write to "reload".
[105682.501898] microcode: Late loading denied: Microcode header does not specify a required min version
root@araj-ucode:/sys/devices/system/cpu/microcode# cat /proc/sys/kernel/tainted 0
4. Offline a primary CPU and attempt to load, must not taint the kernel.
# echo 0 > cpu2/online
[ 378.725868] smpboot: CPU 2 is now offline
#echo 1 > /sys/devices/system/cpu/microcode/reload
[ 388.024968] microcode: Not all CPUs online, aborting microcode update.
#cat /proc/sys/kernel/tainted 0 # echo 1 cpu2/online
[ 398.664452] smpboot: Booting Node 0 Processor 2 APIC 0x4
5. When using the optional patch 9 to override minrev, kernel will be tainted.
root@araj-ucode:/sys/devices/system/cpu/microcode# cat /proc/sys/kernel/tainted 0 echo Y > /sys/kernel/debug/microcode/override_minrev echo 1 > /sys/devices/system/cpu/microcode/reload
[ 491.489986] microcode: Bypassing minrev enforcement via debugfs [ 491.649550] microcode: updated to revision 0x2b000070, date = 2022-08-22 [ 493.595267] microcode: Reload succeeded, microcode revision: 0x2b000041 -> 0x2b000070 [ 493.595360] microcode: Microcode late loading tainted the kernel
root@araj-ucode:/sys/devices/system/cpu/microcode# cat /proc/sys/kernel/tainted 4
[1] https://lore.kernel.org/lkml/20230113172920.113612-1-ashok.raj@intel.com/ [2] https://lore.kernel.org/lkml/87y1pygiyf.ffs@tglx/
Cheers, Ashok
Ashok Raj (9): x86/microcode: Taint kernel only if microcode loading was successful x86/microcode: Report invalid writes to reload sysfs file x86/microcode/intel: Fix collect_cpu_info() to reflect current microcode x86/microcode: Do not call apply_microcode() on sibling threads 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 | 71 +++++++++++++++++++------- arch/x86/kernel/cpu/microcode/intel.c | 71 +++++++++++++++++++++----- arch/x86/Kconfig | 7 +-- 5 files changed, 119 insertions(+), 37 deletions(-)
base-commit: a9a5cac225b0830d1879640e25231a37e537f0da -- 2.37.2
Cc: LKML <linux-kernel@vger.kernel.org> Cc: x86 <x86@kernel.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Tony Luck <tony.luck@intel.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Alison Schofield <alison.schofield@intel.com> Cc: Reinette Chatre <reinette.chatre@intel.com> Cc: Thomas Gleixner (Intel) <tglx@linutronix.de> Cc: Tom Lendacky <thomas.lendacky@amd.com> Cc: Stefan Talpalaru <stefantalpalaru@yahoo.com> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Rafael J. Wysocki <rafael@kernel.org> Cc: Peter Zilstra (Intel) <peterz@infradead.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Andrew Cooper <Andrew.Cooper3@citrix.com> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Martin Pohlack <mpohlack@amazon.de>
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