Re: [Xen-devel] [early RFC] ARM PCI Passthrough design document

[Manish Jaggi <mjaggi@xxxxxxxxxxxxxxxxxx>]

On 01/24/2017 11:13 PM, Julien Grall wrote:
> 
> 
> On 19/01/17 05:09, Manish Jaggi wrote:
>> Hi Julien,
> 
> Hello Manish,
[snip]

>> I think, PCI passthrough and DOM0 w/ACPI enumerating devices on PCI are 
>> separate features.
>> Without Xen mapping PCI config space region in stage2 of dom0, ACPI dom0 
>> wont boot.
>> Currently for dt xen does that.
>>
>> So can we have 2 design documents
>> a) PCI passthrough
>> b) ACPI dom0/domU support in Xen and Linux
>> - this may include:
>> b.1 Passing IORT to Dom0 without smmu
>> b.2 Hypercall to map PCI config space in dom0
>> b.3 <more>
>>
>> What do you think?
> 
> I don't think ACPI should be treated in a separate design document.
As PCI passthrough support will take time to mature, why should we hold the 
ACPI design ?
If I can boot dom0/domU with ACPI as it works with dt today, it would be a good 
milestone.
Later when PCI passthrough design gets mature and implemented the support can 
be extended.
> The support of ACPI may affect some of the decisions (such as hypercall) and 
> we have to know them now.
> 
Still it can be an independent with only dependent features implemented or 
placeholders can be addded
> Regarding the ECAM region not mapped. This is not related to PCI passthrough 
> but how MMIO are mapped with ACPI. This is a separate subject already in 
> discussion (see [1]).
> 
What about IORT generation for Dom0 without smmu ?
I believe, It is not dependent on [1]
> Cheers,
> 
> [1] https://lists.xenproject.org/archives/html/xen-devel/2017-01/msg01607.html
> 

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