[RFC PATCH v4 01/13] iommu: Introduce dirty log tracking framework

[Lu Baolu]

On 5/11/21 3:40 PM, Keqian Zhu wrote:
>> For upper layers, before starting page tracking, they check the
>> dirty_page_trackable attribution of the domain and start it only it's
>> capable. Once the page tracking is switched on the vendor iommu driver
>> (or iommu core) should block further device attach/detach operations
>> until page tracking is stopped.
> But when a domain becomes capable after detaching a device, the upper layer
> still needs to query it and enable dirty log for it...
> 
> To make things coordinated, maybe the upper layer can register a notifier,
> when the domain's capability change, the upper layer do not need to query, instead
> they just need to realize a callback, and do their specific policy in the callback.
> What do you think?
> 

That might be an option. But why not checking domain's attribution every
time a new tracking period is about to start?

Best regards,
baolu