Re: [v7][RFC][PATCH 06/13] hvmloader/ram: check if guest memory is out of reserved device memory maps

["Chen, Tiejun" <tiejun.chen@intel.com>]

On 2014/11/3 20:34, Jan Beulich wrote:
>>>> On 03.11.14 at 12:58, <tiejun.chen@intel.com> wrote:
>> Firstly we have a rule that we just allow all devices associated one
>> RMRR to be assign same VM, right? So I mean while we create VM, we
>> always call current hypercall but inside hypercall, Xen can know which
>> devices will be assigned to this VM.
>
> I.e. the hypercall (at least optionally) becomes per-domain rather
> than global. And you imply that device assignment happens
> before memory getting populated (which likely can be arranged

I tried to find a clue about this point but unfortunately I can't trace 
when we assign device exactly. But in theory, based on your hint I 
prefer the device assignment should follow memory getting populated. 
Because when we add a device, we need to create iommu map so this means 
at this moment the guest should already finish populating memory, right?

Thanks
Tiejun

> for in the tool stack if that's not already the case, but which isn't
> currently mandated by the hypervisor).
>
> Jan
>
>> So Xen still lookup that RMRR list
>> but now Xen would check if these RMRR belongs to that device we want to
>> assign this domain. If yes, we just let that callback go through these
>> RMRR info from that list but exclude other unrelated RMRR. If not, we
>> don't go through any RMRR info so that 'nr_entries' is also zero.
>>
>> Thanks
>> Tiejun
>
>
>