Re: Design doc of adding ACPI support for arm64 on Xen - version 2

[Boris Ostrovsky <boris.ostrovsky@oracle.com>]

On 08/11/2015 11:35 AM, Ian Campbell wrote:
> On Tue, 2015-08-11 at 11:29 -0400, Boris Ostrovsky wrote:
>> On 08/11/2015 10:21 AM, Ian Campbell wrote:
>>> On Tue, 2015-08-11 at 15:19 +0100, Ian Campbell wrote:
>>>> On Fri, 2015-08-07 at 10:11 +0800, Shannon Zhao wrote:
>>>>> This document is going to explain the design details of Xen booting
>>>>> with
>>>>> ACPI on ARM. Maybe parts of it may not be appropriate. Any comments
>>>>> are
>>>>> welcome.
>>>> Some small subsets of this seem like they might overlap with what
>>>> will be
>>>> required for PVH on x86 (a new x86 guest mode not dissimilar to the
>>>> sole
>>>> ARM guest mode). If so then it would be preferable IMHO if PVH x86
>>>> could
>>>> use the same interfaces.
>>>>
>>>> I've trimmed the quotes to just those bits and CCd some of the PVH
>>>> people
>>>> (Boris and Roger[0]) in case they have any thoughts.
>>>>
>>>> Actually, having done the trimming there is only one such bit:
>>>>
>>>> [...]
>>>>> 4. Map MMIO regions
>>>>> -------------------
>>>>> Register a bus_notifier for platform and amba bus in Linux.
>>> Previously PCI was included in this scheme, which is why I thought of
>>> PVH,
>>> having missed that PCI wasn't mentioned here now.
>>>
>>> Is it handled some other way now or is that just an accidental
>>> omission?
>> PCI already has a bus notifier which is probably why it's not explicitly
>> called out here.
> Right, but I was more specifically thinking of the bit which followed
> regarding the use of the notifier to map the MMIO, which is the more
> important bit.

This notifier calls PHYSDEVOP_pci_device_add and as far as I can tell 
MMIO is mapped there (for IOMMU, which IIUIC is the main issue here).

-boris

>
>>>>>    Add a new
>>>>> XENMAPSPACE "XENMAPSPACE_dev_mmio". Within the register, check if
>>>>> the
>>>>> device is newly added, then call hypercall XENMEM_add_to_physmap to
>>>>> map
>>>>> the mmio regions.
>>>> Ian.
>>>>
>>>> [0] Roger is away for a week or so, but I'm expect feedback to be of
>>>> the
>>>> "we could use one extra field" type rather than "this needs to be
>>>> done
>>>> some
>>>> totally different way for x86/PVH" (in which case we wouldn't want to
>>>> share
>>>> the interface anyway I suppose) so need to block on awaiting that
>>>> feedback.
>>
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