x86/microcode/AMD: Handle the case of no BIOS microcode
authorBorislav Petkov (AMD) <bp@alien8.de>
Wed, 20 Aug 2025 09:58:57 +0000 (11:58 +0200)
committerBorislav Petkov (AMD) <bp@alien8.de>
Wed, 27 Aug 2025 08:24:10 +0000 (10:24 +0200)
commitfcf8239ad6a5de54fa7ce18e464c6b5951b982cb
treefe648b78f5f88f97b71bf9fb4e6cd2154aa4827f
parent24963ae1b0b6596dc36e352c18593800056251d8
x86/microcode/AMD: Handle the case of no BIOS microcode

Machines can be shipped without any microcode in the BIOS. Which means,
the microcode patch revision is 0.

Handle that gracefully.

Fixes: 94838d230a6c ("x86/microcode/AMD: Use the family,model,stepping encoded in the patch ID")
Reported-by: Vítek Vávra <vit.vavra.kh@gmail.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Cc: <stable@kernel.org>
arch/x86/kernel/cpu/microcode/amd.c