Re: [PATCH 1/2] x86/amd_node: Remove smn_exclusive

[Jason Andryuk]

On 2026-08-12 15:28, Borislav Petkov wrote:
> On Mon, Aug 10, 2026 at 10:07:47AM -0400, Yazen Ghannam wrote:
> > 'smn_exclusive' wasn't originally intended to be used for bounds
> > checking the array. But the original use is no longer needed, so it can
> > be removed.
>
> Why is it no longer needed? Apparently I didn't get that memo yet...
>
> 83518453074d ("x86/amd_node: Add SMN offsets to exclusive region access") is
> talking about the potential concurrent access. Why is that ok now all of
> a sudden?
83518453074d set smn_exclusive after successfully calling 
pci_request_config_region_exclusive().  smn_exclusive gated access in 
__amd_smn_rw().

Things moved around, and now pci_request_config_region_exclusive() is 
called earlier.  At the end of amd_smn_init(), either amd_roots == NULL 
and smn_exclusive == false or amd_roots != NULL and smn_exclusive == 
true.  smn_exclusive is redundant, and amd_roots can just be used directly.

Regards,
Jason