Re: [RFC 01/10] x86: introduce AMD-V and Intel VT-x Kconfig options

[Xenia Ragiadakou <burzalodowa@xxxxxxxxx>]

On 2/13/23 17:11, Jan Beulich wrote:
> On 13.02.2023 15:57, Xenia Ragiadakou wrote:
> > --- a/xen/arch/x86/Kconfig
> > +++ b/xen/arch/x86/Kconfig
> > @@ -117,6 +117,12 @@ config HVM
> >   
> >   	  If unsure, say Y.
> >   
> > +config AMD_SVM
> > +       def_bool y if HVM
> > +
> > +config INTEL_VMX
> > +       def_bool y if HVM
> I'm not convinced we want vendor names here - I'd prefer to go with
> just SVM and VMX.
Ok, personally I have not strong preferences.

> > --- a/xen/arch/x86/cpu/Makefile
> > +++ b/xen/arch/x86/cpu/Makefile
> > @@ -10,4 +10,6 @@ obj-y += intel.o
> >   obj-y += intel_cacheinfo.o
> >   obj-y += mwait-idle.o
> >   obj-y += shanghai.o
> > -obj-y += vpmu.o vpmu_amd.o vpmu_intel.o
> > +obj-y += vpmu.o
> > +obj-$(CONFIG_AMD_SVM) += vpmu_amd.o
> > +obj-$(CONFIG_INTEL_VMX) += vpmu_intel.o
> This code was moved from hvm/ to cpu/ for the specific reason of also
> being used by PV guests. (Sadly the comments at the top weren't
> corrected at that time.)
Hmm, the init functions are prefixed with svm/vmx.
Does vpmu depend on svm/vmx support?

> > --- a/xen/drivers/passthrough/Kconfig
> > +++ b/xen/drivers/passthrough/Kconfig
> > @@ -51,7 +51,7 @@ config AMD_IOMMU
> >   
> >   config INTEL_IOMMU
> >         bool "Intel VT-d" if EXPERT
> > -       depends on X86
> > +       depends on X86 && INTEL_VMX
> >         default y
> >         help
> >           Enables I/O virtualization on platforms that implement the
> This is odd in three ways: For one PV domains (i.e. incl Dom0) also use
> the IOMMU. And then earlier on there was a change of yours specifically
> relaxing the connection between I/O and CPU virtualization. Plus
> finally you make no similar change for AMD.
I am planning to relax it as it is relevant only to posted interrupts 
(that's why there is no such a dependency for AMD).
> Jan
--
Xenia