Hi Jan,
> On 15 Oct 2021, at 14:00, Jan Beulich <jbeul...@suse.com> wrote:
>
> On 15.10.2021 14:28, Bertrand Marquis wrote:
>>> On 15 Oct 2021, at 13:18, Jan Beulich <jbeul...@suse.com> wrote:
>>> On 15.10.2021 14:13, Bertrand Marquis wrote:
>>>>> On 15 Oct 2021, at 12:35, Roger Pau Monné <roger....@citrix.com> wrote:
>>>>> On Fri, Oct 15, 2021 at 12:18:59PM +0200, Jan Beulich wrote:
>>>>>> On 15.10.2021 12:14, Ian Jackson wrote:
>>>>>>> Bertrand Marquis writes ("Re: [PATCH v6 2/3] xen/arm: Enable the
>>>>>>> existing x86 virtual PCI support for ARM."):
>>>>>>>>> On 15 Oct 2021, at 09:00, Jan Beulich <jbeul...@suse.com> wrote:
>>>>>>>>> The latter is fine to be put here (i.e. FTAOD I'm fine with it
>>>>>>>>> staying here). For the former I even question its original placement
>>>>>>>>> in asm-x86/pci.h: It's not generally correct as per the PCI spec, as
>>>>>>>>> the bus portion of the address can be anywhere from 1 to 8 bits. And
>>>>>>>>> in fact there is a reason why this macro was/is used in only a
>>>>>>>>> single place, but not e.g. in x86'es handling of physical MCFG. It
>>>>>>>>> is merely an implementation choice in vPCI that the entire segment 0
>>>>>>>>> has a linear address range covering all 256 buses. Hence I think
>>>>>>>>> this wants to move to xen/vpci.h and then perhaps also be named
>>>>>>>>> VPCI_ECAM_BDF().
>>>>>>>>
>>>>>>>> On previous version it was request to renamed this to ECAM and agreed
>>>>>>>> to put is here. Now you want me to rename it to VPCI and move it again.
>>>>>>>> I would like to have a confirmation that this is ok and the final move
>>>>>>>> if possible.
>>>>>>>>
>>>>>>>> @Roger can you confirm this is what is wanted ?
>>>>>>>
>>>>>>> I think Roger is not available today I'm afraid.
>>>>>>>
>>>>>>> Bertrand, can you give me a link to the comment from Roger ?
>>>>>>> Assuming that it says what I think it will say:
>>>>>>>
>>>>>>> I think the best thing to do will be to leave the name as it was in
>>>>>>> the most recent version of your series. I don't think it makes sense
>>>>>>> to block this patch over a naming disagreement. And it would be best
>>>>>>> to minimise unnecessary churn.
>>>>>>>
>>>>>>> I would be happy to release-ack a name change (perhaps proposed bo Jan
>>>>>>> or Roger) supposing that that is the ultimate maintainer consensus.
>>>>>>>
>>>>>>> Jan, would that approach be OK with you ?
>>>>>>
>>>>>> Well, yes, if a subsequent name change is okay, then I could live with
>>>>>> that. I'd still find it odd to rename a function immediately after it
>>>>>> already got renamed. As expressed elsewhere, I suspect in his request
>>>>>> Roger did not pay attention to a use of the function in non-ECAM code.
>>>>>
>>>>> Using MMCFG_BDF was original requested by Julien, not myself I think:
>>>>>
>>>>> https://lore.kernel.org/xen-devel/a868e1e7-8400-45df-6eaa-69f1e2c99...@xen.org/
>>>>>
>>>>> I'm slightly loss in so many messages. On x86 we subtract the MCFG
>>>>> start address from the passed one before getting the BDF, and then we
>>>>> add the startting bus address passed in the ACPI table. This is so far
>>>>> not need on Arm AFAICT because of the fixed nature of the selected
>>>>> virtual ECAM region.
>>>>
>>>> At the end my patch will add in xen/pci.h:
>>>> #define ECAM_BDF(addr) (((addr) & 0x0ffff000) >> 12)
>>>
>>> Since you still make this proposal, once again: I'm not going to
>>> accept such a macro in this header, whatever the name. Its prior
>>> placement was wrong as well. Only ...
>>>
>>>> #define ECAM_REG_OFFSET(addr) ((addr) & 0x00000fff)
>>>
>>> ... this one is fine to live here (and presumably it could gain uses
>>> elsewhere).
>>
>> So you would agree if they are both moved to vpci.h with a VPCI_ prefix ?
>
> I wouldn't object, but as said several times before I see no reason
> to also move and rename ECAM_REG_OFFSET(). If you moved it and if
> later we find a use for it outside of vPCI, we'd need to rename and
> move it again.
I will move BDF to vpci.h and had VPCI prefix and keep REG_OFFSET as
it is and where it is then.
Cheers
Bertrand
>
> Jan
>
