Re: [Xen-devel] [PATCH 2/4] sysctl/libxl: Add interface for returning IO topology data

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 08.12.14 at 15:56, <boris.ostrovsky@xxxxxxxxxx> wrote:

>>>> Additionally please add IN and OUT annotations. When I first saw
>>>> this I assumed they would all be OUT (in which case the long running
>>>> loop problem mentioned in the reply to one of the other patches
>>>> wouldn't have been there), matching their CPU counterpart...
>>> I don't follow this. Are you saying that if ti->max_devs in patch 3/4 is
>>> an IN (which it is) then we don't have to guard for long-running loops?
>> If they were all OUT then there wouldn't be a way for the entire
>> operation to be fooled into going over more devices than there are
>> in the system.
> 
> Assuming I add continuations to the loop, too many devices wouldn't be a 
> problem for the hypervisor, would it? If an unreasonable number is 
> provided then eventually copy_from_guest() will fault.

Continuations would address the concern, but it doesn't seem like
their use is really warranted here.

Jan


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