From 2467f4f8cb7cb2878088265858bf13fa3b2e95f6 Mon Sep 17 00:00:00 2001 From: "Borislav Petkov (AMD)" Date: Fri, 1 Dec 2023 19:37:27 +0100 Subject: [PATCH] x86/CPU/AMD: Check vendor in the AMD microcode callback commit 9b8493dc43044376716d789d07699f17d538a7c4 upstream. Commit in Fixes added an AMD-specific microcode callback. However, it didn't check the CPU vendor the kernel runs on explicitly. The only reason the Zenbleed check in it didn't run on other x86 vendors hardware was pure coincidental luck: if (!cpu_has_amd_erratum(c, amd_zenbleed)) return; gives true on other vendors because they don't have those families and models. However, with the removal of the cpu_has_amd_erratum() in 05f5f73936fa ("x86/CPU/AMD: Drop now unused CPU erratum checking function") that coincidental condition is gone, leading to the zenbleed check getting executed on other vendors too. Add the explicit vendor check for the whole callback as it should've been done in the first place. Fixes: 522b1d69219d ("x86/cpu/amd: Add a Zenbleed fix") Cc: Signed-off-by: Borislav Petkov (AMD) Link: https://lore.kernel.org/r/20231201184226.16749-1-bp@alien8.de Signed-off-by: Greg Kroah-Hartman --- arch/x86/kernel/cpu/amd.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c index b66960358381b..c1d09c8844d67 100644 --- a/arch/x86/kernel/cpu/amd.c +++ b/arch/x86/kernel/cpu/amd.c @@ -1291,6 +1291,9 @@ static void zenbleed_check_cpu(void *unused) void amd_check_microcode(void) { + if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD) + return; + on_each_cpu(zenbleed_check_cpu, NULL, 1); } -- 2.47.3