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

[Xenia Ragiadakou <burzalodowa@xxxxxxxxx>]

On 12/21/22 09:51, Jan Beulich wrote:
> On 19.12.2022 07:34, Xenia Ragiadakou wrote:
> > --- a/xen/drivers/passthrough/Kconfig
> > +++ b/xen/drivers/passthrough/Kconfig
> > @@ -37,6 +37,22 @@ config IPMMU_VMSA
> >   
> >   endif
> >   
> > +config AMD_IOMMU
> > +       bool "AMD IOMMU"
> > +       depends on X86
> > +       default y
> > +       ---help---
> > +         Enables I/O virtualization on platforms that implement the
> > +         AMD I/O Virtualization Technology (IOMMU).
> > +
> > +config INTEL_VTD
> > +       bool "Intel VT-d"
> > +       depends on X86
> > +       default y
> > +       ---help---
> > +         Enables I/O virtualization on platforms that implement the
> > +         Intel Virtualization Technology for Directed I/O (Intel VT-d).
> One more thing Andrew and I have been talking about: As he has mentioned
> elsewhere, IOMMU support is needed to boot systems with more than 254
> CPUs (depending on APIC ID layout the boundary may actually be lower).
> Hence it needs to at least be considered to make the prompts here (to
> be precise: in the much later patch adding the prompts) dependent on
> EXPERT, to prevent people from unknowingly building a non-functioning
> (on some systems) hypervisor.
I will mention it in help as Andrew suggested and I will make it visible 
only if EXPERT.
> Jan
--
Xenia