Re: [PATCH V3 04/23] xen/ioreq: Make x86's IOREQ feature common

[Oleksandr <olekstysh@gmail.com>]

On 08.12.20 11:21, Jan Beulich wrote:

Hi Jan

> On 07.12.2020 20:43, Oleksandr wrote:
>> On 07.12.20 13:41, Jan Beulich wrote:
>>> On 30.11.2020 11:31, Oleksandr Tyshchenko wrote:
>>>> @@ -38,42 +37,6 @@ int arch_ioreq_server_get_type_addr(const struct domain *d,
>>>>                                        uint64_t *addr);
>>>>    void arch_ioreq_domain_init(struct domain *d);
>>> As already mentioned in an earlier reply: What about these? They
>>> shouldn't get declared once per arch. If anything, ones that
>>> want to be inline functions can / should remain in the per-arch
>>> header.
>> Don't entirely get a suggestion. Is the suggestion to make "simple" ones
>> inline? Why not, there are a few ones which probably want to be inline,
>> such as the following for example:
>> - arch_ioreq_domain_init
>> - arch_ioreq_server_destroy
>> - arch_ioreq_server_destroy_all
>> - arch_ioreq_server_map_mem_type (probably)


First of all, thank you for the clarification, now your point is clear 
to me.


> Before being able to make a suggestion, I need to have my question
> answered: Why do the arch_*() declarations live in the arch header?
> They represent a common interface (between common and arch code)
> and hence should be declared in exactly one place.

I got it, I had a wrong assumption that arch hooks declarations should 
live in arch code.


> It is only at
> the point where you/we _consider_ making some of them inline that
> moving those (back) to the arch header may make sense. Albeit even
> then I'd prefer if only the ones get moved which are expected to
> be inline for all arch-es. Others would better have the arch header
> indicate to the common one that no declaration is needed (such that
> the declaration still remains common for all arch-es using out-of-
> line functions).
I got it as well.

Well, I think, in order to address your comments two options are available:
1. All arch hooks are out-of-line: мove all arch hook declarations to 
the common header here and modify
"[PATCH V3 14/23] arm/ioreq: Introduce arch specific bits for IOREQ/DM 
features" to make all Arm variants
out-of-line (I made them inline since all of them are just stubs).
2. Some of arch hooks are inline: consider which want to be inline (for 
both arch-es) and place them into arch headers, other ones
should remain in the common header.

My question is which option is more suitable?


-- 
Regards,

Oleksandr Tyshchenko