Re: [PATCH 7/9] x86/sev-es: Include XSS value in GHCB CPUID request

From: Borislav Petkov
Date: Tue Oct 17 2023 - 14:49:58 EST


On Tue, Oct 17, 2023 at 01:12:30PM -0500, John Allen wrote:
> I looked into using __rdmsr in an earlier revision of the patch, but
> found that it causes a build warning:
>
> ld: warning: orphan section `__ex_table' from `arch/x86/boot/compressed/sev.o' being placed in section `__ex_table'
>
> This is due to the __ex_table section not being used during
> decompression boot. Do you know of a way around this?

Yeah, arch/x86/boot/msr.h.

We did those a while ago. I guess they could be moved to
asm/shared/msr.h and renamed to something that is not a
"boot_" prefix.

Something like

rdmsr_without_any_exception_handling_and_other_gunk_don_t_you_even_think_of_adding()

...

But srsly:

raw_rdmsr()
raw_wrmsr()

should be good, as tglx suggests offlist.

You can do that in one patch and prepend your set with it.

Thx.

--
Regards/Gruss,
Boris.

https://people.kernel.org/tglx/notes-about-netiquette