Re: [PATCH v3 2/8] xen/common: dom0less: make some parts of Arm's CONFIG_DOM0LESS common

["Orzel, Michal" <michal.orzel@xxxxxxx>]

On 05/05/2025 09:35, Oleksii Kurochko wrote:
> 
> On 5/2/25 7:55 PM, Stefano Stabellini wrote:
>> On Fri, 2 May 2025, Oleksii Kurochko wrote:
>>> Move some parts of Arm's Dom0Less code to be reused by other architectures.
>>> At the moment, RISC-V is going to reuse these parts.
>>>
>>> Move dom0less-build.h from the Arm-specific directory to asm-generic
>>> as these header is expected to be the same across acrhictectures with
>>> some updates: add the following declaration of construct_domU(),
>>> and arch_create_domUs() as there are some parts which are still
>>> architecture-specific.
>>>
>>> Introduce HAS_DOM0LESS to provide ability to enable generic Dom0less
>>> code for an architecture.
>>>
>>> Relocate the CONFIG_DOM0LESS configuration to the common with adding
>>> "depends on HAS_DOM0LESS" to not break builds for architectures which
>>> don't support CONFIG_DOM0LESS config, especically it would be useful
>>> to not provide stubs for  construct_domU(), arch_create_domUs()
>>> in case of *-randconfig which may set CONFIG_DOM0LESS=y.
>>>
>>> Move is_dom0less_mode() function to the common code, as it depends on
>>> boot modules that are already part of the common code.
>>>
>>> Move create_domUs() function to the common code with some updates:
>>> - Add arch_create_domUs() to cover parsing of arch-specific features,
>>>   for example, SVE (Scalar Vector Extension ) exists only in Arm.
>>>
>>> Signed-off-by: Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>
>>> ---
>>> It was suggested to change dom0less to predefined domus or similar
>>> (https://lore.kernel.org/xen-devel/cd2a3644-
>>> c9c6-4e77-9491-2988703906c0@xxxxxxxxx/T/
>>> #m1d5e81e5f1faca98a3c51efe4f35af25010edbf0):
>>>
>>> I decided to go with dom0less name for now as it will require a lot of 
>>> places to change,
>>> including CI's test, and IMO we could do in a separate patch.
>>> If it is necessry to do now, I'll be happy to do that in next version of 
>>> the current
>>> patch series.
>> I think it is fine to use dom0less for now, it will make the code easier
>> to review and it is not necessary to change the name at this point.
>>
>> The patch looks good to me, except for a couple of minor suggestions I
>> have below. I could make them on commit. With those:
>>
>> Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>
> 
> Thanks.
> 
> I will apply the suggestions below (unless they have already been committed 
> by the time I start preparing the new version of the patch series).

NIT: please trim down your replies (unless you want to show the bigger context,
which is not necessary here)

I only skimmed through the patch and noticed you did not add EMACS comment in
dom0less-build.c. Please do.

~Michal