The following commit has been merged into the x86/microcode branch of tip: Commit-ID: 07cc5639f14dcc3763a926dbe7cc38ac2694de0c Gitweb: https://git.kernel.org/tip/07cc5639f14dcc3763a926dbe7cc38ac2694de0c Author: Borislav Petkov (AMD) <bp@xxxxxxxxx> AuthorDate: Sat, 15 Apr 2023 16:23:29 +02:00 Committer: Borislav Petkov (AMD) <bp@xxxxxxxxx> CommitterDate: Mon, 17 Apr 2023 15:38:33 +02:00 x86/microcode/AMD: Document which patches are not released for late loading PeterZ wanted this spelled out explicitly. Add it to the documentation so that everyone's on the same page wrt to which microcode patches are not allowed to be late loaded. Suggested-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> Signed-off-by: Borislav Petkov (AMD) <bp@xxxxxxxxx> Link: https://lore.kernel.org/r/20230415142821.24725-1-bp@xxxxxxxxx --- Documentation/x86/microcode.rst | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/Documentation/x86/microcode.rst b/Documentation/x86/microcode.rst index 15b52e2..d5ef918 100644 --- a/Documentation/x86/microcode.rst +++ b/Documentation/x86/microcode.rst @@ -218,6 +218,10 @@ a fault happens, the whole core will see it either before the microcode patch has been applied or after. In either case, T0 and T1 will have the same microcode revision and nothing intermediate. +In addition, microcode patches which modify software-visible features +like CPUID bits, MSRs, chicken bits, etc are not released for late +loading. + Builtin microcode =================
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