On Sun, Mar 12, 2023 at 08:47:36PM -0000, tip-bot2 for Borislav Petkov (AMD) wrote:
> The following commit has been merged into the x86/microcode branch of tip:
>
> Commit-ID: 09b951476df9eadf15f2acba7568fa35e4b2313b
> Gitweb: https://git.kernel.org/tip/09b951476df9eadf15f2acba7568fa35e4b2313b
> Author: Borislav Petkov (AMD) <bp@xxxxxxxxx>
> AuthorDate: Fri, 03 Mar 2023 12:46:49 +01:00
> Committer: Borislav Petkov (AMD) <bp@xxxxxxxxx>
> CommitterDate: Sun, 12 Mar 2023 21:32:51 +01:00
>
> x86/microcode: Do not taint when late loading on AMD
>
> Describe why the concurrency issues which late loading poses are not
> affecting AMD hardware, after discussing it with hw folks. Thus, do not
> taint when late loading on it.
>
> Signed-off-by: Borislav Petkov (AMD) <bp@xxxxxxxxx>
> Link: https://lore.kernel.org/r/20230303114649.18552-1-bp@xxxxxxxxx
Forgot to adjust the error message too. Updated patch coming up.
diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c
index 779f70547fb7..22cf57c899b6 100644
--- a/arch/x86/kernel/cpu/microcode/core.c
+++ b/arch/x86/kernel/cpu/microcode/core.c
@@ -440,9 +440,6 @@ static int microcode_reload_late(void)
int old = boot_cpu_data.microcode, ret;
struct cpuinfo_x86 prev_info;
- pr_err("Attempting late microcode loading - it is dangerous and taints the kernel.\n");
- pr_err("You should switch to early loading, if possible.\n");
-
atomic_set(&late_cpus_in, 0);
atomic_set(&late_cpus_out, 0);
@@ -498,8 +495,11 @@ static ssize_t reload_store(struct device *dev,
if (ret == 0)
ret = size;
- if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD)
+ if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD) {
+ pr_err("Late microcode loading is dangerous and taints the kernel.\n");
+ pr_err("You should switch to early loading if possible.\n");
add_taint(TAINT_CPU_OUT_OF_SPEC, LOCKDEP_STILL_OK);
+ }
return ret;
}
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
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