Re: [XEN PATCH v1 01/15] x86: introduce AMD-V and Intel VT-x Kconfig options

[Jan Beulich <jbeulich@xxxxxxxx>]

On 16.04.2024 08:20, Sergiy Kibrik wrote:
> From: Xenia Ragiadakou <burzalodowa@xxxxxxxxx>
> 
> Introduce two new Kconfig options, SVM and VMX, to allow code
> specific to each virtualization technology to be separated and, when not
> required, stripped.
> CONFIG_SVM will be used to enable virtual machine extensions on platforms that
> implement the AMD Virtualization Technology (AMD-V).
> CONFIG_VMX will be used to enable virtual machine extensions on platforms that
> implement the Intel Virtualization Technology (Intel VT-x).
> 
> Both features depend on HVM support.
> 
> Since, at this point, disabling any of them would cause Xen to not compile,
> the options are enabled by default if HVM and are not selectable by the user.
> 
> No functional change intended.
> 
> Signed-off-by: Xenia Ragiadakou <burzalodowa@xxxxxxxxx>
> Signed-off-by: Sergiy Kibrik <Sergiy_Kibrik@xxxxxxxx>

In the subject tag you say v1, but I think this is a re-post? In which
case and with it having been a long time since then it would be even
more so important that a proper revision log is present in each individual
patch.

> --- a/xen/arch/x86/Kconfig
> +++ b/xen/arch/x86/Kconfig
> @@ -120,6 +120,12 @@ config HVM
>  
>         If unsure, say Y.
>  
> +config SVM
> +     def_bool y if HVM
> +
> +config VMX
> +     def_bool y if HVM

It was probably me to have requested this form, but meanwhile I've learned
(on the Linux side) that newer kconfig is capable to dealing with

config SVM
        def_bool HVM

config VMX
        def_bool HVM

quite fine (i.e. no longer leaving around useless "# CONFIG_... is not set"
when (in this case) HVM=n. Please double check with the kconfig we use
whether that's the case there, too, and simplify if so.

> --- a/xen/arch/x86/mm/Makefile
> +++ b/xen/arch/x86/mm/Makefile
> @@ -10,6 +10,7 @@ obj-$(CONFIG_MEM_SHARING) += mem_sharing.o
>  obj-$(CONFIG_HVM) += nested.o
>  obj-$(CONFIG_HVM) += p2m.o
>  obj-y += p2m-basic.o
> -obj-$(CONFIG_HVM) += p2m-ept.o p2m-pod.o p2m-pt.o
> +obj-$(CONFIG_HVM) += p2m-pod.o p2m-pt.o
> +obj-$(CONFIG_VMX) += p2m-ept.o

Please can these be kept in alphabetical order?

Jan