linux-kernel - Re: sev_es_trampoline_start undefined symbol referenced errors during kunit run

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Message-ID: <CABVgOS=LyuJEXDHzRaqsBK9HJEqquvfYQS9uVDM=uF75LwQrLA@mail.gmail.com>
Date: Tue, 15 Apr 2025 16:54:44 +0800
From: David Gow <davidgow@...gle.com>
To: Borislav Petkov <bp@...en8.de>
Cc: Shuah Khan <skhan@...uxfoundation.org>, thomas.lendacky@....com, 
	"x86@...nel.org" <x86@...nel.org>, Brendan Higgins <brendan.higgins@...ux.dev>, linux-kernel@...r.kernel.org, 
	Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>
Subject: Re: sev_es_trampoline_start undefined symbol referenced errors during
 kunit run

On Tue, 15 Apr 2025 at 07:01, Borislav Petkov <bp@...en8.de> wrote:
>
> On Mon, Apr 14, 2025 at 04:28:44PM -0600, Shuah Khan wrote:

... snip ...

>
> The real problem looks like that pasyms.h thing which gets included at the end
> of realmode.lds and which contains that symbol.

I had a look at this a few months ago, and came to the same
conclusion: that realmode.lds is where the issue is coming from. My
suspicion was that realmode.lds was being generated when the kernel
was built in-tree (with CONFIG_AMD_MEM_ENCRYPT), but somehow was not
being deleted when the source tree was being cleaned before an
out-of-tree build was being done (without CONFIG_AMD_MEM_ENCRYPT).

But, alas, I was never able to find a way to reproduce this to test it
out: realmode.lds seems to be properly deleted by make clean / make
mrproper here.

(My personal strategy is to always do out-of-tree builds, which may be
why I don't tend to randomly come across this. Equally, it may be
worth trying `--build_dir .` as an argument to kunit.py to force an
in-tree build if you're already doing in-tree builds often.)

Cheers,
-- David

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