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

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20231017184932.GBZS7XPESSMgPoCysY@fat_crate.local>
Date:   Tue, 17 Oct 2023 20:49:32 +0200
From:   Borislav Petkov <bp@...en8.de>
To:     John Allen <john.allen@....com>
Cc:     kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
        pbonzini@...hat.com, weijiang.yang@...el.com,
        rick.p.edgecombe@...el.com, seanjc@...gle.com, x86@...nel.org,
        thomas.lendacky@....com
Subject: Re: [PATCH 7/9] x86/sev-es: Include XSS value in GHCB CPUID request

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