Re: [RFC 1/7] x86/iommu: make AMD-Vi and Intel VT-d support configurable

[Xenia Ragiadakou <burzalodowa@xxxxxxxxx>]

On 12/20/22 19:01, Jan Beulich wrote:
> On 19.12.2022 07:34, Xenia Ragiadakou wrote:
> > Currently, for x86 platforms, Xen does not provide to the users any
> > configuration control over the IOMMU support and can only be built with
> > both AMD and Intel IOMMU drivers enabled.
> > However, there are use cases, e.g in safety-critical systems, that require
> > Xen to be able to be configured to exclude unused code. A smaller tailored
> > configuration would help Xen to meet faster certification requirements for
> > individual platforms.
> >
> > Introduce two new Kconfig options, AMD_IOMMU and INTEL_VTD, to allow code
> > specific to each IOMMU technology to be separated and, when not required,
> > stripped. AMD_IOMMU enables IOMMU support for platforms that implement the
> > AMD I/O Virtualization Technology. INTEL_VTD enables IOMMU support for
> > platforms that implement the Intel Virtualization Technology for Directed I/O.
> >
> > Since no functional change is intended regarding the default configuration
> > of an x86 system, both options depend on x86 and default to 'y'.
> But do things also build successfully when one or both options are disabled?
> I have to say that I would be quite surprised if that worked without further
> adjustments. In which case initially these options want to be prompt-less,
> with the prompts only added once 'n' also works.
Without applying the whole series, disabling any of them or both won't 
work. Ok.
> Jan
--
Xenia