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* [PATCH 0/6] x86/cpu: Take Intel platform into account for old microcode checks
@ 2026-01-19 19:50 Dave Hansen
  2026-01-19 19:50 ` [PATCH 1/6] x86/cpu: Break Vendor/Family/Model macros into separate header Dave Hansen
                   ` (7 more replies)
  0 siblings, 8 replies; 37+ messages in thread
From: Dave Hansen @ 2026-01-19 19:50 UTC (permalink / raw)
  To: linux-kernel
  Cc: sohil.mehta, Dave Hansen, Borislav Petkov, H. Peter Anvin,
	Ingo Molnar, Jon Kohler, Pawan Gupta, Peter Zijlstra (Intel),
	Thomas Gleixner, Tony Luck, x86

There was a report[1] that CPUs running updated microcode were being
reported as running old microcode. The reason is that the old
microcode list neglects to take the platform ID into account.

The platform ID is an Intel-only construct that allows CPUs that
otherwise have the same model/family/stepping to take different
microcode revisions. The microcode loader itself already checks this.
Only the recent "old_microcode" checker failed here.

Treat the platform ID as a peer of model/family/stepping. Store it
in 'struct cpuinfo_x86', enable matching on it with with 'struct
x86_cpu_id', and flesh out the 'old_microcode' list with it.

This fixes the report of an inaccurate, false positive in the
'old_microcode' vulnerability file.

1. https://lore.kernel.org/all/38660F8F-499E-48CD-B58B-4822228A5941@nutanix.com/

Cc: Thomas Gleixner <tglx@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org>
Cc: x86@kernel.org
Cc: Jon Kohler <jon@nutanix.com>

^ permalink raw reply	[flat|nested] 37+ messages in thread
* [PATCH 0/6] [v2] x86/cpu: Take Intel platform into account for old microcode checks
@ 2026-02-06 23:14 Dave Hansen
  2026-02-06 23:14 ` [PATCH 6/6] x86/microcode: Add platform mask to Intel microcode "old" list Dave Hansen
  0 siblings, 1 reply; 37+ messages in thread
From: Dave Hansen @ 2026-02-06 23:14 UTC (permalink / raw)
  To: linux-kernel
  Cc: sohil.mehta, zhao1.liu, Dave Hansen, Borislav Petkov,
	H. Peter Anvin, Ingo Molnar, Jon Kohler, Pawan Gupta,
	Peter Zijlstra (Intel), Thomas Gleixner, Tony Luck, x86

Changes from v1:
 * Fix non-x86 PECI compile issues by lifting some x86 macros
   into an arch-independent header.
 * Make intel_get_platform_id() match its name and return an ID,
   not a mask.
 * Sort #includes
 * Move ->x86_platform_id comment

The platform ID vs. platform mask confusion meant that v1
worked by total accident. If you tested v1, I'd really
appreciate you retest this as well.

--

There was a report[1] that CPUs running updated microcode were being
reported as running old microcode. The reason is that the old
microcode list neglects to take the platform ID into account.

The platform ID is an Intel-only construct that allows CPUs that
otherwise have the same model/family/stepping to take different
microcode revisions. The microcode loader itself already checks this.
Only the recent "old_microcode" checker failed here.

Treat the platform ID as a peer of model/family/stepping. Store it
in 'struct cpuinfo_x86', enable matching on it with with 'struct
x86_cpu_id', and flesh out the 'old_microcode' list with it.

This fixes the report of an inaccurate, false positive in the
'old_microcode' vulnerability file.

1. https://lore.kernel.org/all/38660F8F-499E-48CD-B58B-4822228A5941@nutanix.com/

Cc: Thomas Gleixner <tglx@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org>
Cc: x86@kernel.org
Cc: Jon Kohler <jon@nutanix.com>

^ permalink raw reply	[flat|nested] 37+ messages in thread

end of thread, other threads:[~2026-02-10 23:40 UTC | newest]

Thread overview: 37+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2026-01-19 19:50 [PATCH 0/6] x86/cpu: Take Intel platform into account for old microcode checks Dave Hansen
2026-01-19 19:50 ` [PATCH 1/6] x86/cpu: Break Vendor/Family/Model macros into separate header Dave Hansen
2026-01-20  8:24   ` Andy Shevchenko
2026-01-20 15:03     ` Dave Hansen
2026-01-20 16:22       ` Andy Shevchenko
2026-01-20 16:34         ` Dave Hansen
2026-01-20 20:54           ` Andy Shevchenko
2026-01-20 16:48     ` Luck, Tony
2026-01-20 20:50       ` Shevchenko, Andriy
2026-01-19 19:50 ` [PATCH 2/6] x86/cpu: Add missing #include Dave Hansen
2026-01-20  0:26   ` Dave Hansen
2026-01-20  8:19     ` Andy Shevchenko
2026-01-20 15:35       ` Dave Hansen
2026-01-19 19:50 ` [PATCH 3/6] x86/microcode: Refactor platform ID enumeration into a helper Dave Hansen
2026-01-20  3:07   ` Chao Gao
2026-01-20 16:06     ` Dave Hansen
2026-01-20 20:59       ` Andy Shevchenko
2026-01-22 19:26   ` Sohil Mehta
2026-01-19 19:50 ` [PATCH 4/6] x86/cpu: Add platform ID to CPU info structure Dave Hansen
2026-01-20  3:14   ` Chao Gao
2026-01-20 15:22     ` Dave Hansen
2026-01-21  2:03       ` Chao Gao
2026-01-20  8:27   ` Andy Shevchenko
2026-01-20 15:06     ` Dave Hansen
2026-01-20 20:44       ` Andy Shevchenko
2026-01-20 20:48         ` Dave Hansen
2026-01-19 19:50 ` [PATCH 5/6] x86/cpu: Add platform ID to CPU matching structure Dave Hansen
2026-01-20  8:30   ` Andy Shevchenko
2026-01-20 15:09     ` Dave Hansen
2026-01-19 19:51 ` [PATCH 6/6] x86/microcode: Add platform mask to Intel microcode "old" list Dave Hansen
2026-01-20 14:33   ` Zhao Liu
2026-01-20 15:10     ` Dave Hansen
2026-01-29 21:23   ` Sohil Mehta
2026-01-20 18:18 ` [PATCH 0/6] x86/cpu: Take Intel platform into account for old microcode checks Dave Hansen
2026-01-22 13:56 ` Ricardo Neri
  -- strict thread matches above, loose matches on Subject: below --
2026-02-06 23:14 [PATCH 0/6] [v2] " Dave Hansen
2026-02-06 23:14 ` [PATCH 6/6] x86/microcode: Add platform mask to Intel microcode "old" list Dave Hansen
2026-02-10 23:39   ` Sohil Mehta

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