Re: [PATCH v3 2/6] x86/amd_nb: Restrict NB framework init to AMD vendor

[Yazen Ghannam]

On Thu, Jul 09, 2026 at 03:55:45PM +0800, Lin Wang wrote:
> Drop the X86_VENDOR_HYGON branch from init_amd_nbs() and
> early_is_amd_nb().  Both functions are entry points to the AMD NB
> framework, which uses the legacy fixed-slot PCI enumeration model
> (slot 0x18+i for node i) and the AMD-only amd_nb_misc_ids[] device-ID
> table.
> 
> On Hygon Family 0x18, these paths do not find usable AMD NB entries:
> amd_cache_northbridges() probes the AMD fixed slots, while
> early_is_amd_nb() matches only AMD IDs from amd_nb_misc_ids[].
> 
> Restrict these AMD framework entry points to AMD vendor.  Hygon DF
> enumeration is added separately in arch/x86/kernel/hygon_node.c.
> 
> No user-visible functional regression on Hygon Fam18h.
> 
> amd_get_mmconfig_range() is intentionally left unchanged: it reads
> the MSR_FAM10H_MMIO_CONF_BASE shared CPU MSR and serves
> arch/x86/pci/amd_bus.c and drivers/pnp/quirks.c on Hygon platforms.
> 
> Signed-off-by: Lin Wang <wanglin@xxxxxxxxxxxxxx>

Reviewed-by: Yazen Ghannam <yazen.ghannam@xxxxxxx>

Thanks,
Yazen