linux-kernel - Re: [PATCH] x86: also disable FSRM if ERMS is disabled

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Message-ID: <b0b18b83-0b6b-ea89-b701-0375b8302d1e@kernel.org>
Date:   Mon, 16 Jan 2023 06:26:50 +0100
From:   Jiri Slaby <jirislaby@...nel.org>
To:     Borislav Petkov <bp@...en8.de>
Cc:     Daniel Verkamp <dverkamp@...omium.org>, x86@...nel.org,
        linux-kernel@...r.kernel.org, Tony Luck <tony.luck@...el.com>
Subject: Re: [PATCH] x86: also disable FSRM if ERMS is disabled

On 04. 01. 23, 12:39, Borislav Petkov wrote:
> On Wed, Jan 04, 2023 at 08:43:51AM +0100, Jiri Slaby wrote:
>> Let me resurrect this thread... Our customer has an AMD CPU which has indeed
>> both capabilities under normal circumstances. But they have a cool UEFI BIOS
>> too. They say:
>>
>> """
>> In AMD platform, while disalbe ERMS(Enhanced Rep MOVSB/STOSB) in UEFI
>> (system setup -> processor -> Enhanced Rep MOVSB/STOSB), the OS can't boot
>> normally.
> 
> Any particular reason they're disabling ERMS?

Just so you know (I see you progressed with Ingo to fix this) -- despite 
I asked the very same question, I received no answer quite yet. I 
suppose it will sound like usual "because we can".

> What do they set FSRM to?

I suppose they keep it "enabled".

thanks,
-- 
js
suse labs