Re: [Xen-users] Grant iomem access and map IRQs to a domU guest in Xen for ARM targets

[Arianna Avanzini <avanzini.arianna@xxxxxxxxx>]

On 06/16/2014 11:52 PM, Kapania, Ashish wrote:
>> -----Original Message-----
>> From: Dario Faggioli [mailto:dario.faggioli@xxxxxxxxxx]
>> Sent: Thursday, June 12, 2014 12:26 AM
>> To: Kapania, Ashish
>> Cc: Ian Campbell; xen-users@xxxxxxxxxxxxx; Arianna Avanzini
>> Subject: Re: [Xen-users] Grant iomem access and map IRQs to a domU
>> guest in Xen for ARM targets
>>
>> On mer, 2014-06-11 at 22:00 +0000, Kapania, Ashish wrote:
>>
>>> We are not tied to a particular Xen version just yet. I am working
>>> with the master branch (from a few weeks ago) i.e. xen4.5 dev branch
>> I
>>> believe.
>>>
>> That's what I was assuming, basing also on what you said yourself, but
>> I wasn't sure... Great! :-)
>>
>>> I can try applying Arianna's patches.
>>>
>> Awesome. Let the list know how it goes.
>>
> 
> I tried Arianna's patches over the weekend. After applying the patches, I
> am able to use "iomem" field in xl.cfg to allow domU access to the
> specified memory ranges. So, the patches work for me.
> 

Hello,

Thank you for writing back with feedback.

> While trying the changes, I found that I need to have the device memory
> ranges declared in dom0's device tree in order to be able to map them to
> domU using "iomem". Otherwise, they are not in dom0's iomem_caps and I get
> an error. Just wanted to confirm that this is by design ?
> 

Yes, with this patchset the I/O-memory ranges you want to make available to a
domU must be described in the dom0's device tree. This limitation of the current
implementation has been pointed out by Julien Grall in his comments to the v6
patchset ([1]).

As far as I remember, he is currently working on a follow-up to this series that
will allow to use the iomem option even on memory ranges that are not described
in the device tree ([2]). I believe that he will include it in his upcoming
patch series for device passthrough.

(I'm adding Julien Grall as Cc so that he can correct me if needed)

Thank you,
Arianna

[1] http://markmail.org/message/vpfgajirmcxp66fj
[2] http://markmail.org/message/hai4bip5oeh2e3kv


> Best,
> Ashish
> 


-- 
/*
 * Arianna Avanzini
 * avanzini.arianna@xxxxxxxxx
 * 73628@xxxxxxxxxxxxxxxxxxx
 */

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