linux-kernel - RE: [PATCH v3 3/6] x86/microcode: Display revisions only when update is successful

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <SJ1PR11MB6083BD0E0191061B72A47982FCFB9@SJ1PR11MB6083.namprd11.prod.outlook.com>
Date:   Fri, 6 Jan 2023 21:35:41 +0000
From:   "Luck, Tony" <tony.luck@...el.com>
To:     Borislav Petkov <bp@...en8.de>, "Raj, Ashok" <ashok.raj@...el.com>
CC:     Thomas Gleixner <tglx@...utronix.de>, X86-kernel <x86@...nel.org>,
        "LKML Mailing List" <linux-kernel@...r.kernel.org>,
        "Hansen, Dave" <dave.hansen@...el.com>,
        "Schofield, Alison" <alison.schofield@...el.com>,
        "Chatre, Reinette" <reinette.chatre@...el.com>,
        Tom Lendacky <thomas.lendacky@....com>
Subject: RE: [PATCH v3 3/6] x86/microcode: Display revisions only when update
 is successful

> We issue that line unconditionally to give feedback to the user that the attempt
> was actually tried. Otherwise, you don't get any feedback and you wonder whether
> it is doing anything.
>
> The prev and next revision:
>
>	"microcode revision: 0x%x -> 0x%x\n",
>
> will tell you whether something got loaded or not.

Seems like a very subtle indication of a possibly important failure.

E.g. There is some security update with new microcode to mitigate.

User downloads the new microcode. Runs:

# echo 1 > /sys/devices/system/cpu/microcode/reload

	[This fails for some reason]

Looks at console

# dmesg | tail -1
microcode revision: 0x40001a -> 0x4001a

User doesn't notice that the version didn't change and thinks
that all is well.

Is there an earlier message that says something like this?

microcode: initiating update to version 0x5003f

-Tony