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

From: David Vrabel
Date: Fri Jul 24 2015 - 05:48:18 EST


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.

David
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