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Date:   Wed, 9 Aug 2023 12:04:16 +0300
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Subject: Re: [RFC][PATCH 00/17] Fix up the recent SRSO patches
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To:     Peter Zijlstra <peterz@infradead.org>, x86@kernel.org
Cc:     linux-kernel@vger.kernel.org, David.Kaplan@amd.com,
        Andrew.Cooper3@citrix.com, jpoimboe@kernel.org,
        gregkh@linuxfoundation.org
References: <20230809071218.000335006@infradead.org>
From:   Nikolay Borisov <nik.borisov@suse.com>
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On 9.08.23 г. 10:12 ч., Peter Zijlstra wrote:
> Since I wasn't invited to the party (even though I did retbleed), I get to
> clean things up afterwards :/
> 
> Anyway, this here overhauls the SRSO patches in a big way.
> 
> I claim that AMD retbleed (also called Speculative-Type-Confusion -- not to be
> confused with Intel retbleed, which is an entirely different bug) is
> fundamentally the same as this SRSO -- which is also caused by STC. And the
> mitigations are so similar they should all be controlled from a single spot and
> not conflated like they are now.
> 
> As such, at the end of the ride the new kernel command line and srso sysfs
> files are no more and all we're left with is a few extra retbleed options.
> 
> Aside of that; this deals with a few implementation issues -- but not all known
> issues. Josh and Andrew are telling me there's a problem when running inside
> virt due to how this checks the microcode. I'm hoping either of those two gents
> will add a patch to address this.

The microcode issue should have been fixed as Boris added a safe_wrmsr 
call which checks for the presence of SBPB bit on zen3/4.


> 
> 
>