Re: [Xen-devel] [RFC PATCH v3 08/18] xen/arm: vITS: Add virtual ITS driver

[Vijay Kilari <vijay.kilari@xxxxxxxxx>]

Hi Julien,

On Tue, Jun 23, 2015 at 10:09 PM, Julien Grall <julien.grall@xxxxxxxxxx> wrote:
> Hi Vijay,
>
>>
>> +struct vits_device {
>> +    uint32_t vdevid;
>> +    uint32_t pdevid;
>> +    struct its_device *its_dev;
>> +    struct rb_node node;
>> +};
>
> We spoke about a specific structure in the design [2] but you introduced
> a new one. Why?

Section 6 of DraftG specifies to manage separate tree for device assignment.
This helps to manage RB-tree per domain to hold list of devices
assigned to this domain index with vdevid.

This helps to check if device is assigned to this domain before processing
any ITS command with that vdevid.

>
> Having everything in the its_device would help to catch a device
> attached to 2 different domains...

One option is to introduce a new variable inside its_device to know
to which domain the device is currently assigned.

>
> Also, the field pdevid is not vits specific but its.
pdevid can be removed as its_device structure already has it

Regards
Vijay

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