linux-kernel - Re: [PATCH v3 3/4] x86/alternative: Rewrite optimize

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Message-ID: <Y+QNlx3VmeStqz+X@hirez.programming.kicks-ass.net>
Date:   Wed, 8 Feb 2023 22:01:11 +0100
From:   Peter Zijlstra <peterz@...radead.org>
To:     Andrew.Cooper3@...rix.com
Cc:     x86@...nel.org, linux-kernel@...r.kernel.org, mhiramat@...nel.org,
        kirill.shutemov@...ux.intel.com, jpoimboe@...hat.com
Subject: Re: [PATCH v3 3/4] x86/alternative: Rewrite optimize_nops() some

On Wed, Feb 08, 2023 at 09:44:04PM +0100, Peter Zijlstra wrote:

> Works as advertised. Next up are 8 12 byte nopes and 8 13 byte nops,
> after that we're left with:

Yeah, we can ignore those, those are the retpoline thunks being patched.
They should be totally unused. These NOPs are after an indirect jmp and
as such pure speculation food.

Arguably I should just merge that patch that turns them into UD2 --
funneling and all that.

But there was some i386 issues... oh well.