From: Borislav Petkov <bp@alien8.de>
To: linux-kernel@vger.kernel.org
Cc: linux-tip-commits@vger.kernel.org, x86@kernel.org
Subject: Re: [tip: x86/microcode] x86/microcode: Do not taint when late loading on AMD
Date: Tue, 11 Apr 2023 14:48:32 +0200 [thread overview]
Message-ID: <20230411124832.GAZDVXIFR3BiExtXba@fat_crate.local> (raw)
In-Reply-To: <167865405614.5837.13144930108431641081.tip-bot2@tip-bot2>
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@alien8.de>
> AuthorDate: Fri, 03 Mar 2023 12:46:49 +01:00
> Committer: Borislav Petkov (AMD) <bp@alien8.de>
> 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@alien8.de>
> Link: https://lore.kernel.org/r/20230303114649.18552-1-bp@alien8.de
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
next prev parent reply other threads:[~2023-04-11 12:48 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-03 11:46 [PATCH] " Borislav Petkov
2023-03-12 20:47 ` [tip: x86/microcode] " tip-bot2 for Borislav Petkov (AMD)
2023-04-11 12:48 ` Borislav Petkov [this message]
2023-04-11 12:50 ` [PATCH -v2] " Borislav Petkov
2023-04-14 10:38 ` [tip: x86/microcode] " tip-bot2 for Borislav Petkov (AMD)
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20230411124832.GAZDVXIFR3BiExtXba@fat_crate.local \
--to=bp@alien8.de \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-tip-commits@vger.kernel.org \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox
Powered by JetHome