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 2014/11/11 18:07, Jan Beulich wrote:
>>>> On 11.11.14 at 10:42, <tiejun.chen@intel.com> wrote:
>> On 2014/11/11 17:06, Jan Beulich wrote:
>>> Part of which would involve re-considering whether device
>>> assignment shouldn't be done before memory population in the
>>> tool stack.
>>>
>>
>> Yes, after we introduce this new domctl, we just make sure this domctl
>> should be called before memory population no matter when we do assign a
>> device as passthrough.
>
> You didn't think through the implications then: If device assignment
> happens early enough, there's no need to report SBDF tuples via a

In the present the device assignment is always after memory population. 
And I also mentioned previously I double checked this sequence with printk.

> new domctl (or only if we want to still allow for post-boot assignment
> of affected devices without using the global enforcement flag, in
> which case assigning devices early at boot time is pointless).

The global enforcement flag is mainly used to provide such an approach 
the user know exactly he/she may need a hotplug later, we'd better check 
to reserve all RMRR ranges in advance.

So I guess you mean we need to separate this interface from our original 
device assignment like this,

#1 pci_force as a global variable would control whether we force to 
check/reserve __all__ RMRR ranges.

#2 flags field in each specific device of new domctl would control 
whether this device need to check/reserve its own RMRR range. But its 
not dependent on current device assignment domctl, so the user can use 
them to control which devices need to work as hotplug later, separately. 
This means we should introduce new parameters just like current 'pci' 
construction, right? Or extend current device assignment to be 
compatible with this case, for instance, new field to indicate if we 
really want to do device assignment in boot time.

Thanks
Tiejun