Re: [Xen-devel] [PATCH 02/11] xen/arm: vpl011: Add new hvm params in Xen for ring buffer/event setup

[Bhupinder Thakur <bhupinder.thakur@xxxxxxxxxx>]

Hi,

Kindly let me know if my understanding is correct.

Using a domctl API will allow us to keep the vUART configuration
flexible. Currently, we can operate on one ring-buf PFN and an event
channel port only for a single vUART but if we use DOMCTL interface,
then we can effectively get/set multiple event channel ports/multiple
PFNs from/to Xen in a single domctl call.

I am not clear who will be the caller of this domctl API. Is it
xenconsoled or the toolstack? Currently, xenconsoled reads the
ring-buf PFN and event channel from the xenstore, which is populated
by the toolstack.

Regards,
Bhupinder

On 8 March 2017 at 23:52, Stefano Stabellini <sstabellini@xxxxxxxxxx> wrote:
> On Wed, 8 Mar 2017, Jan Beulich wrote:
>> >>> On 08.03.17 at 15:45, <julien.grall@xxxxxxx> wrote:
>> > I was looking at the backend code and see it is using DOMCTL command. I
>> > guess it is considered that the console backend will be tied to a
>> > specific Xen version. Am I correct?
>>
>> I don't think I'm qualified to talk about the console backend
>> implementation (and possible quirks it has). Generally I'd expect
>> backends not to use domctl-s, as that would tie them to the tool
>> stack domain.
>>
>> > so maybe we can introduce new domctl command for handling vUART. This
>> > would avoid us to commit on an ABI and allow us to extend it if
>> > necessary in the future to support multiple UARTs.
>>
>> Well, without having the context of who it would be to use such a
>> domctl (and for what purpose) I don#t think I can comment here.
>
> I guess the assumption was that xenconsoled was part of the Xen tools.
> Indeed, it is part of the tools and is installed as such.
>
> I don't have an opinion on this. If introducing a new DOMCTL makes the
> code nicer in xen and xenconsoled, taking away some edges, like the
> changes to evtchn_send, then we should probably just do it.

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
https://lists.xen.org/xen-devel