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From: Borislav Petkov <bp@alien8.de>
To: Tavis Ormandy <taviso@gmail.com>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>,
	linux-kernel@vger.kernel.org, x86@kernel.org
Subject: Re: x86: AMD Zen2 ymm registers rolling back
Date: Wed, 22 Feb 2023 23:25:02 +0100	[thread overview]
Message-ID: <Y/aWPuo2MNrl7RXB@zn.tnic> (raw)
In-Reply-To: <Y/aIjUr78yd9U+wl@thinkstation.cmpxchg8b.net>

On Wed, Feb 22, 2023 at 01:26:37PM -0800, Tavis Ormandy wrote:
> Thanks - confirmed, it *doesn't* repro with 0x8301055, but does repro
> with 0x830104d.

Good.

> Annoyingly, I thought I was using the most recent microcode, but it seems
> like there is some bug and debian wasn't applying it at boot.

Well, actually, microcode loading is so simple - you don't absolutely
need to rely on the distros to do it for ya.

You simply get it from

git://git.kernel.org/pub/scm/linux/kernel/git/firmware/linux-firmware.git

and copy all the bin files from amd-ucode/ into /lib/firmware/amd-ucode/

Technically, you'd need only the one for your family but the tools can
deal with multiple files in there.

And then you're all set - dracut or whatever creates your initrd will
add it. You can even add it by hand, see

Documentation/x86/microcode.rst

> That seems like a scary errata :-/

Yeah, modern x86 hardware is crazy complex. And we've had worse. :-\

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette

  parent reply	other threads:[~2023-02-22 22:25 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-02-22  6:40 x86: AMD Zen2 ymm registers rolling back Tavis Ormandy
2023-02-22  8:33 ` Borislav Petkov
2023-02-22  9:14   ` Borislav Petkov
2023-02-22  9:38     ` Andrew Cooper
2023-02-22 10:09       ` Borislav Petkov
2023-02-22 21:26         ` Tavis Ormandy
2023-02-22 22:17           ` Andrew Cooper
2023-02-22 22:26             ` Borislav Petkov
2023-02-22 22:25           ` Borislav Petkov [this message]
2023-02-28 18:47         ` Alexander Monakov
2023-02-28 19:20           ` Borislav Petkov
2023-02-28 19:24             ` Alexander Monakov
2023-02-28 19:25               ` Borislav Petkov
2023-02-28 19:29                 ` Alexander Monakov
2023-02-28 19:38                   ` Andrew Cooper
2023-02-28 21:45                     ` Alexander Monakov
2023-02-28 20:56                   ` Borislav Petkov
2023-02-28 21:16                     ` Alexander Monakov
2023-03-01  0:23                       ` Andrew Cooper
2023-03-01  8:54                         ` Borislav Petkov
2023-03-07 16:45                           ` Tavis Ormandy
2023-03-07 17:46 ` [PATCH] x86/amd: Work around Erratum 1386 - XSAVES malfunction on context switch Andrew Cooper
2023-03-07 17:50   ` Borislav Petkov
2023-03-07 18:22     ` Andrew Cooper
2023-03-07 18:56       ` Borislav Petkov
2023-03-07 20:01         ` Andrew Cooper
2023-03-07 20:09           ` Borislav Petkov
2023-03-14 16:01           ` Dave Hansen
2023-03-08 16:23   ` [tip: x86/urgent] x86/CPU/AMD: Disable XSAVES on AMD family 0x17 tip-bot2 for Andrew Cooper

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