Re: [RFC v2 1/1] memory: Delete assertion in memory_region_unregister_iommu_notifier

On 2020/7/3 下午9:03, Peter Xu wrote: > On Fri, Jul 03, 2020 at 03:24:19PM +0800, Jason Wang wrote: > > On 2020/7/2 下午11:45, Peter Xu wrote: > > > On Thu, Jul 02, 2020 at 11:01:54AM +0800, Jason Wang wrote: > > > > So I think we agree that a new notifier is needed? > > > Good to me, or a new flag should be easier (IOMMU_NOTIFIER_DEV_IOTLB)? > > > > That should work but I wonder something as following is better. > > > > Instead of introducing new flags, how about carry the type of event in the > > notifier then the device (vhost) can choose the message it want to process > > like: > > > > static vhost_iommu_event(IOMMUNotifier *n, IOMMUTLBEvent *event) > > > > { > > > > switch (event->type) { > > > > case IOMMU_MAP: > > case IOMMU_UNMAP: > > case IOMMU_DEV_IOTLB_UNMAP: > > ... > > > > } > Looks ok to me, though imo we should still keep the registration information, > so VT-d knows which notifiers is interested in which events. E.g., we can > still do something like vtd_as_has_map_notifier(). Is this for a better performance? I wonder whether it's worth since we can't not have both vhost and vtd to be registered into the same as.

So it should be functional equivalent to vtd_as_has_notifier().