Re: [Qemu-devel] [RFC PATCH 12/20] Memory: Add func to fire pasidt_bind notifier

[Liu, Yi L]

On Wed, Apr 26, 2017 at 03:50:16PM +0200, Paolo Bonzini wrote:
> 
> 
> On 26/04/2017 12:06, Liu, Yi L wrote:
> > +void memory_region_notify_iommu_svm_bind(MemoryRegion *mr,
> > +                                         void *data)
> > +{
> > +    IOMMUNotifier *iommu_notifier;
> > +    IOMMUNotifierFlag request_flags;
> > +
> > +    assert(memory_region_is_iommu(mr));
> > +
> > +    /*TODO: support other bind requests with smaller gran,
> > +     * e.g. bind signle pasid entry
> > +     */
> > +    request_flags = IOMMU_NOTIFIER_SVM_PASIDT_BIND;
> > +
> > +    QLIST_FOREACH(iommu_notifier, &mr->iommu_notify, node) {
> > +        if (iommu_notifier->notifier_flags & request_flags) {
> > +            iommu_notifier->notify(iommu_notifier, data);
> > +            break;
> > +        }
> > +    }
> 
> Peter,
> 
> should this reuse ->notify, or should it be different function pointer
> in IOMMUNotifier?

Hi Paolo,

Thx for your review.

I think it should be “->notify” here. In this patchset, the new notifier
is registered with the existing notifier registration API. So the all the
notifiers are in the mr->iommu_notify list. And notifiers are labeled
by notify flag, so it is able to differentiate the IOMMUNotifier nodes.
When the flag meets, trigger it by “->notify”. The diagram below shows
my understanding , wish it helps to make me understood.

VFIOContainer
       |
       giommu_list(VFIOGuestIOMMU)
                \
                 VFIOGuestIOMMU1 ->   VFIOGuestIOMMU2 -> VFIOGuestIOMMU3 ...
                    |                     |                 |
mr->iommu_notify: IOMMUNotifier   ->    IOMMUNotifier  ->  IOMMUNotifier
                  (Flag:MAP/UNMAP)     (Flag:SVM bind)  (Flag:tlb invalidate)


Actually, compared with the MAP/UNMAP notifier, the newly added notifier has
no start/end check, and there may be other types of bind notfier flag in
future, so I added a separate fire func for SVM bind notifier.

Thanks,
Yi L

> Paolo
>