linux-kernel - Re: x86: AMD Zen2 ymm registers rolling back

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Date:   Wed, 1 Mar 2023 00:45:08 +0300 (MSK)
From:   Alexander Monakov <amonakov@...ras.ru>
To:     Andrew Cooper <andrew.cooper3@...rix.com>
cc:     Borislav Petkov <bp@...en8.de>, Tavis Ormandy <taviso@...il.com>,
        linux-kernel@...r.kernel.org, x86@...nel.org
Subject: Re: x86: AMD Zen2 ymm registers rolling back


On Tue, 28 Feb 2023, Andrew Cooper wrote:

> On 28/02/2023 7:29 pm, Alexander Monakov wrote:
> > On Tue, 28 Feb 2023, Borislav Petkov wrote:
> >
> > That I can reproduce the bug even with the latest BIOS, i.e. the microcode
> > in the latest BIOS update does not have the fix, and the linux-firmware.git
> > microcode does not have a patch for this CPU family at all.
> >
> > Hence the question how to get fixed microcode for this CPU family.
> 
> I shouldn't be recommending this, but I've begged AMD many times to be
> better at publishing microcode...
> 
> https://github.com/platomav/CPUMicrocodes
> 
> and you'll need
[snip script]

Thank you, this is good to have. Unfortunately, even with microcode 0x08600109
taken from that repo the issue is reproducible (it is dated 2022-03-28, so
perhaps not really surprising).

Alexander