Hi keqian,
On 5/12/21 4:44 PM, Keqian Zhu wrote:
On 2021/5/12 11:20, Lu Baolu wrote:
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?
Hi Baolu,
I'll add an attribution in iommu_domain, and the vendor iommu driver will update
the attribution when attach/detach devices.
The attribute should be protected by a lock, so the upper layer shouldn't access
the attribute directly. Then the iommu_domain_support_dirty_log() still should
be
retained. Does this design looks good to you?
Yes, that's what I was thinking of. But I am not sure whether it worth
of a lock here. It seems not to be a valid behavior for upper layer to
attach or detach any device while doing the dirty page tracking.
Best regards,
baolu
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