Re: [PATCH v2] x86/hvm: add HVM-specific Kconfig

[Denis Mukhin <dmkhn@xxxxxxxxx>]

On Friday, March 14th, 2025 at 1:20 PM, Andrew Cooper 
<andrew.cooper3@xxxxxxxxxx> wrote:

> 
> 
> On 13/03/2025 2:39 am, dmkhn@xxxxxxxxx wrote:
> 
> > diff --git a/xen/arch/x86/hvm/Kconfig b/xen/arch/x86/hvm/Kconfig
> > new file mode 100644
> > index 0000000000..2ca664f36f
> > --- /dev/null
> > +++ b/xen/arch/x86/hvm/Kconfig
> > @@ -0,0 +1,76 @@
> > +menuconfig HVM
> > + bool "HVM support"
> > + depends on !PV_SHIM_EXCLUSIVE
> > + default !PV_SHIM
> > + select COMPAT
> > + select IOREQ_SERVER
> > + select MEM_ACCESS_ALWAYS_ON
> > + help
> > + Interfaces to support HVM domains. HVM domains require hardware
> > + virtualisation extensions (e.g. Intel VT-x, AMD SVM), but can boot
> > + guests which have no specific Xen knowledge.
> > +
> > + This option is needed if you want to run HVM or PVH domains.
> > +
> > + If unsure, say Y.
> > +
> > +if HVM
> > +
> > +menu "Hardware Support for Virtualization"
> > +
> > +config AMD_SVM
> > + bool "AMD-V" if AMD && EXPERT
> > + default y
> > + help
> > + Enables virtual machine extensions on platforms that implement the
> > + AMD Virtualization Technology (AMD-V).
> > + If your system includes a processor with AMD-V support, say Y.
> > + If in doubt, say Y.
> > +
> > +config INTEL_VMX
> > + bool "Intel VT-x" if INTEL && EXPERT
> > + default y
> > + select ARCH_VCPU_IOREQ_COMPLETION
> > + help
> > + Enables virtual machine extensions on platforms that implement the
> > + Intel Virtualization Technology (Intel VT-x).
> > + If your system includes a processor with Intel VT-x support, say Y.
> > + If in doubt, say Y.
> > +
> > +endmenu
> 
> 
> Looking at the end result, I'd suggest dropping the menu around SVM and VMX.
> 
> It would be nice to group them under a name called Vendor Support, but I
> don't think the Kconfig language can express this, and the full menu
> becomes empty if both AMD and INTEL are deselected.
> 
> Having them simply at the top of the HVM menu seems like the less bad
> option.
> 
> There is a bunch of cleanup which should be done, but explicitly not in
> this patch which is simply restructuring. I'll do a patch in due course.

Addressed:
  https://lore.kernel.org/xen-devel/20250315011945.2927542-1-dmukhin@xxxxxxxx

Thanks!

> 
> ~Andrew