[PATCH 00/13] Make microcode loading more robust

[Ashok Raj]

This series adds more robustness to microcode loading.

- Adds proper quiesce to sibling threads in an NMI handler.
- Fixes some nasty early loading bugs that are there for a long time.
- Adds a minimum revision ID to Intel patch meta-data, requested by Thomas.
- Turns microcode late loading back on by default.
- Adds some debugfs support to provide ability to test the microcode flows
  without the need for a new microcode.

This series has too many changes from previous post, but for anecdotal
references. 

https://lore.kernel.org/lkml/20220817051127.3323755-1-ashok.raj@xxxxxxxxx/

Here is a summary of those patches.

patch1: Allow printing the old and new rev during an early update
patch2: Fix a potential bug during CPU hot-add flow for microcode update.
patch3: Fixes a nasty early loading bug that locks up with endless retries.
patch4: Add a helper to perform self NMI
patch5: Drop siblings in NMI while primary thread updates the microcode.
patch6: Rename refresh_fw to late_loading, in preparation for min-rev patches.
patch7: Move late loading warning to the same function as where taint happens.
patch8: Adds support for microcode meta-data to declare a minimum version 
patch9: Add a generic way to declare support for min-rev across vendors.
patch10: Drop wbinvd(), its not required after patch7.
patch11: Print microcode updated messages only when its successfully loaded
patch12: Issue a warning if MCE arrives while a microcode update is in progress.
patch13: Debug patch: To permit testing repeated loading of microcode.

Ashok Raj (12):
  x86/microcode/intel: Print old and new rev after early microcode
    update
  x86/microcode: Do not load from filesystem for CPU hot add
  x86/microcode/intel: Fix a hang if early loading microcode fails
  x86/microcode: Place siblings in NMI loop while update in progress
  x86/microcode: Rename refresh_fw to late_loading
  x86/microcode: Move late-load warning to earlier where kernel taint
    happens
  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: Display revisions only when update is successful
  x86/mce: Warn of a microcode update is in progress when MCE arrives
  x86/microcode/intel: Add ability to update microcode even if rev is
    unchanged

Jacob Pan (1):
  x86/x2apic: Support x2apic self IPI with NMI_VECTOR

 arch/x86/include/asm/microcode.h       |  39 ++++++-
 arch/x86/include/asm/microcode_intel.h |   4 +-
 arch/x86/kernel/apic/x2apic_phys.c     |   6 +-
 arch/x86/kernel/cpu/mce/core.c         |   5 +
 arch/x86/kernel/cpu/microcode/amd.c    |   6 +-
 arch/x86/kernel/cpu/microcode/core.c   | 156 ++++++++++++++++++++++---
 arch/x86/kernel/cpu/microcode/intel.c  |  85 +++++++++-----
 arch/x86/kernel/cpu/microcode/nmi.c    |  72 ++++++++++++
 arch/x86/kernel/nmi.c                  |   7 ++
 arch/x86/Kconfig                       |   7 +-
 arch/x86/kernel/cpu/microcode/Makefile |   1 +
 11 files changed, 332 insertions(+), 56 deletions(-)
 create mode 100644 arch/x86/kernel/cpu/microcode/nmi.c

-- 
2.34.1