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Date:   Tue, 27 Sep 2022 13:36:08 -0700
From:   Kees Cook <keescook@chromium.org>
To:     Nick Desaulniers <ndesaulniers@google.com>
Cc:     Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        Dave Hansen <dave.hansen@linux.intel.com>, x86@kernel.org,
        "H . Peter Anvin" <hpa@zytor.com>,
        Peter Zijlstra <peterz@infradead.org>,
        linux-kernel@vger.kernel.org,
        Linus Torvalds <torvalds@linux-foundation.org>,
        llvm@lists.linux.dev, Andy Lutomirski <luto@kernel.org>
Subject: Re: [PATCH v2] x86, mem: move memmove to out of line assembler
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On Tue, Sep 27, 2022 at 01:01:35PM -0700, Nick Desaulniers wrote:
> > Found it (need to use %di instead of %dx). With this changed, the kunit
> > test passes again:
> >
> 
> That was stupid of me, I updated the scratch register operand in the
> instruction 2 before the one at issue and forgot to update the operand
> for the register in question, breaking the swap.

No worries! It meant I got to do a very careful review of the port. :)

> Off thread, can you show me how to run the kunit tests, please?

It's literally just what I put in the original email. KUnit is super
easy to use. In the root of the kernel source tree, just run:

	./tools/testing/kunit/kunit.py run --arch=i386 memcpy

Without --arch, it'll default to um.

-- 
Kees Cook