Re: [PATCH v2 1/4] xen: kconfig: rename MEM_ACCESS -> VM_EVENT

[Jan Beulich <jbeulich@suse.com>]

On 21.01.2025 11:19, Sergiy Kibrik wrote:
> Use more generic CONFIG_VM_EVENT name throughout Xen code instead of
> CONFIG_MEM_ACCESS. This reflects the fact that vm_event is a higher level
> feature, with mem_access & monitor depending on it.
> 
> Suggested-by: Jan Beulich <jbeulich@suse.com>

I don't think this is applicable; my suggestion went in a different direction.

> Suggested-by: Tamas K Lengyel <tamas@tklengyel.com>
> Signed-off-by: Sergiy Kibrik <Sergiy_Kibrik@epam.com>

Before considering to ack this, I'd like you, Tamas, to confirm this is really
what you had thought of. In particular ...

> --- a/xen/arch/arm/Makefile
> +++ b/xen/arch/arm/Makefile
> @@ -37,7 +37,7 @@ obj-y += irq.o
>  obj-y += kernel.init.o
>  obj-$(CONFIG_LIVEPATCH) += livepatch.o
>  obj-$(CONFIG_LLC_COLORING) += llc-coloring.o
> -obj-$(CONFIG_MEM_ACCESS) += mem_access.o
> +obj-$(CONFIG_VM_EVENT) += mem_access.o

... changes like this one look somewhat odd to me.

> --- a/xen/common/Kconfig
> +++ b/xen/common/Kconfig
> @@ -92,7 +92,7 @@ config HAS_VMAP
>  config MEM_ACCESS_ALWAYS_ON
>  	bool
>  
> -config MEM_ACCESS
> +config VM_EVENT
>  	def_bool MEM_ACCESS_ALWAYS_ON
>  	prompt "Memory Access and VM events" if !MEM_ACCESS_ALWAYS_ON
>  	depends on HVM

What about MEM_ACCESS_ALWAYS_ON (visible in patch context)? Shouldn't that
become VM_EVENT_ALWAYS_ON then, too?

Further, what about MEM_PAGING and MEM_SHARING? Shouldn't those, at least
documentation purposes, then also gain a dependency on VM_EVENT?

Jan