Re: [Xen-devel] [PATCH v4.1 4/6] xen/x86: Allow stubdom access to irq created for msi.

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 08.03.19 at 17:49, <marmarek@xxxxxxxxxxxxxxxxxxxxxx> wrote:
> On Fri, Mar 08, 2019 at 11:26:28AM +0100, Roger Pau Monné wrote:
>> On Thu, Mar 07, 2019 at 11:28:25PM +0100, Marek Marczykowski-Górecki wrote:
>> > Can one HVM domain have multiple stubdomains? If so, it should a be
>> > list, not a single field.
>> 
>> Yes, I think that's a supported setup. You can register multiple ioreq
>> servers handling accesses for a single domain, and there's no
>> restriction that forces running all those ioreq servers in the same
>> control domain.
> 
> I was looking at it, and adding a list of struct domain pointers would
> be easy, but would require breaking circular dependency during teardown
> (in domain_kill). And will add yet another struct list_head into
> struct domain. On the other hand, having list of domain ids would
> require a wrapper structure or such - I don't see any API in Xen for
> storing list of just ints (domid_t specifically). Using an array for
> something that should really be a list looks clumsy - all the searching
> for first available space, ignoring empty slots etc. Maybe rangeset
> could be used for that?

For one rangesets are meant primarily for things which come in
(consecutive) groups, which doesn't seem like a god fit here. And
then its overhead is even higher (especially for the common case
of just a single stubdom) compared to the simplest dynamic form
of allocating and maintaining an array of suitable size (in which
case you'd probably not even need to skip empty slots or serach
for available space).

Jan


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/xen-devel