Re: [PATCH 2/2] x86/Kconfig: Introduce CONFIG_{AMD,INTEL} and conditionalise ucode

[Jan Beulich <jbeulich@xxxxxxxx>]

On 25.10.2023 20:06, Andrew Cooper wrote:
> We eventually want to be able to build a stripped down Xen for a single
> platform.  Make a start with CONFIG_{AMD,INTEL} (hidden behind EXPERT, but
> available to randconfig), and adjust the microcode logic.

Linux uses different names for the Kconfig symbols. While I'm unconvinced
of the SUP part, I wonder whether we wouldn't better use CPU in the names.
One immediate question here is how the IOMMU interaction is intended to
end up: Do we want to permit either vendor's CPUs with the other vendor's
IOMMUs to be usable?

> --- /dev/null
> +++ b/xen/arch/x86/Kconfig.cpu
> @@ -0,0 +1,22 @@
> +menu "Supported processor vendors"
> +     visible if EXPERT
> +
> +config AMD
> +     bool "AMD"
> +        default y
> +        help
> +          Detection, tunings and quirks for AMD processors.
> +
> +       May be turned off in builds targetting other vendors.  Otherwise,
> +       must be enabled for Xen to work suitably on AMD processors.
> +
> +config INTEL
> +     bool "Intel"
> +        default y
> +        help
> +          Detection, tunings and quirks for Intel processors.
> +
> +       May be turned off in builds targetting other vendors.  Otherwise,
> +       must be enabled for Xen to work suitably on Intel processors.
> +
> +endmenu

Nit: Throughout this hunk there's an inconsistency with indentation
(hard tabs not used in some places where they ought to be).

Also, depending on the verdict on the aspect mentioned at the top,
"processors" may want replacing by "systems" or "platforms" or some
such if we mean these to cover more than just the CPUs.

Jan