Re: [RFC v2 1/1] memory: Delete assertion in memory_region_unregister_iommu_notifier
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().
So these are probably two different things: the new IOMMU_NOTIFIER_DEV_IOTLB
flag is one as discussed; the other one is whether we would like to introduce
IOMMUTLBEvent to include the type, so that we can avoid introduce two notifiers
for one device majorly to identify dev-iotlb from unmaps.
Thanks,
--
Peter Xu