Re: [PATCH v3 02/14] x86/sev: Make the VMPL0 checking function more generic

[Borislav Petkov]

On Wed, Apr 17, 2024 at 03:35:53PM -0500, Tom Lendacky wrote:
> Well, it doesn't really modify any permissions that matter. It tries to
> change the permission of a lesser privileged VMPL level.

Potato potato. :-P

> Since the kernel only runs at a single VMPL it would never be
> effected. The operation performed here is to update VMPL1 permission
> levels (which can only be done successfully at VMPL0) and return the
> result of the operation.  A success implies running at VMPL0 and
> failure implies not running at VMPL0.

Yap.

The point is, it is calling RMPADJUST. And it does modify RMP
permissions of a guest page.

Thus, if you prefer, you can go all out and call the helper

	rmp_adjust_permissions(unsigned int tgt_vmpl, void *pa)

and make it generic from the get-go.

And then have the macro wrap around it in order to explain that
particular use with the macro name.

If it is still not clear what I mean, lemme know and I'll do a diff
ontop.

Thx.

-- 
Regards/Gruss,
    Boris.

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