Re: [Xen-devel] [PATCH v2 01/20] xen: Add Xen specific page definition

From: Julien Grall
Date: Fri Jul 24 2015 - 05:52:55 EST


On 24/07/15 10:48, David Vrabel wrote:
> On 24/07/15 10:39, Julien Grall wrote:
>> Hi David,
>>
>> On 24/07/15 10:28, David Vrabel wrote:
>>> On 09/07/15 21:42, Julien Grall wrote:
>>>> The Xen hypercall interface is always using 4K page granularity on ARM
>>>> and x86 architecture.
>>>>
>>>> With the incoming support of 64K page granularity for ARM64 guest, it
>>>> won't be possible to re-use the Linux page definition in Xen drivers.
>>>>
>>>> Introduce Xen page definition helpers based on the Linux page
>>>> definition. They have exactly the same name but prefixed with
>>>> XEN_/xen_ prefix.
>>>>
>>>> Also modify page_to_pfn to use new Xen page definition.
>>>>
>>>> Signed-off-by: Julien Grall <julien.grall@xxxxxxxxxx>
>>>> Cc: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
>>>> Cc: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
>>>> Cc: David Vrabel <david.vrabel@xxxxxxxxxx>
>>>> ---
>>>> I'm wondering if we should drop page_to_pfn has the macro will likely
>>>> misuse when Linux is using 64KB page granularity.
>>>
>>> I think we want xen_gfn_to_page() and xen_page_to_gfn() and Xen
>>> front/back drivers never deal with PFNs only GFNs.
>>
>> What is xen_gfn_to_page and xen_page_to_gfn? Neither Linux, nor my
>> series have them.
>
> I suggesting that you introduce these.

It's still not clear to me what you are suggesting here... Do you
suggest to rename xen_pfn_to_page and xen_page_to_pfn by xen_gfn_to_page
and xen_page_to_gfn?

Regards,

--
Julien Grall
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