Re: sev_es_trampoline_start undefined symbol referenced errors during kunit run

[Shuah Khan]

On 4/15/25 16:29, Shuah Khan wrote:
> On 4/15/25 16:17, Borislav Petkov wrote:
> > On Tue, Apr 15, 2025 at 01:06:49PM -0600, Shuah Khan wrote:
> > > Does your arch/x86/realmode/rm/pasyms.h has reference to sev_es_trampoline_start?
> > >
> > > The one in my tree has it.
> > >
> > > arch/x86/realmode/rm/pasyms.h:pa_sev_es_trampoline_start = sev_es_trampoline_start
> >
> >
> > # ./tools/testing/kunit/kunit.py run --arch x86_64
> > ...
> >
> > [00:15:36] Elapsed time: 58.840s total, 2.096s configuring, 53.170s building, 3.487s running
> >
> > # cat arch/x86/realmode/rm/pasyms.h
> > cat: arch/x86/realmode/rm/pasyms.h: No such file or directory
> >
> > Could explain why I don't see the issue...
>
> I see arch/x86/realmode/rm/pasyms.h on my system. It is a generated
> file from arch/x86/realmode/rm Makefile
>
> Here is the target information.
>
> REALMODE_OBJS = $(addprefix $(obj)/,$(realmode-y))
>
> sed-pasyms := -n -r -e 's/^([0-9a-fA-F]+) [ABCDGRSTVW] (.+)$$/pa_\2 = \2;/p'
>
> quiet_cmd_pasyms = PASYMS  $@
>        cmd_pasyms = $(NM) $(real-prereqs) | sed $(sed-pasyms) | sort | uniq > $@
>
> targets += pasyms.h
> $(obj)/pasyms.h: $(REALMODE_OBJS) FORCE
>          $(call if_changed,pasyms)
>
> The key is how and why this file gets generated and why the reference
>
> pa_sev_es_trampoline_start = sev_es_trampoline_start
>
> is added unconditionally even when  CONFIG_AMD_MEM_ENCRYPT is not
> enabled. I think the logic should be fixed to take AMD_MEM_ENCRYPT
> enabled or disabled into account when this pasyms.h file is generated.

Okay - I think the logic to extract symbols to include in pasyms.h
will have to take AMD_MEM_ENCRYPT enabled vs. disabled into account.

running git grep sev_es_trampoline_start in arch/x86/realmode/rm shows:

header.S:       .long   pa_sev_es_trampoline_start
trampoline_64.S:SYM_CODE_START(sev_es_trampoline_start)
trampoline_64.S:SYM_CODE_END(sev_es_trampoline_start)

All of the above are under ifdef AMD_MEM_ENCRYPT conditional.
Even if pasyms.h is generated sev_es_trampoline_start should not
be included in pasyms.h if AMD_MEM_ENCRYPT is disabled.

thanks,
-- Shuah