Re: [PATCH v3 0/2] x86: enforce and cleanup RIP-relative accesses in early boot code

[Jacob Xu]

On Wed, Jan 31, 2024 at 6:01 AM Borislav Petkov <bp@xxxxxxxxx> wrote:
>
> On Tue, Jan 30, 2024 at 10:08:43PM +0000, Kevin Loughlin wrote:
> > Instead, this patchset continues the approach of fixing the immediate
> > problem of SEV-SNP boots crashing when built by clang, providing a
> > backport-friendly set of changes needed to successfully boot SEV-SNP
> > hosts and guests.
>
> What use cases are those exactly? How do I reproduce them here?
>

We're interested in fixing SEV-SNP guest boots which are currently
broken when using a guest kernel compiled with clang. It seems like
every other user of SEV/SNP linux kernel code uses GCC to compile the
kernel so they've avoided this issue.

> SNP is not upstream yet and the SEV* code has been out there for a while
> now without a single such report so this must be something new happening
> due to <raisins>...?

E.g. Google COS uses clang to compile the kernel and we've made do
with an internal fix for a while. We've unfortunately just been rather
slow to report upstream.


>
> Thx.
>
> --
> Regards/Gruss,
>     Boris.
>
> https://people.kernel.org/tglx/notes-about-netiquette