On Mon, Dec 19, 2016 at 11:53:32AM +0000, Liu, Yi L wrote: [...]
> > > Regards to the s->notifiers_list, I didn't see the init op to it. Does it > > > happen > > > in another patch? If so, it may be better to move it in this patch since > > > this > > > patch introduces both the definition and usage of notifiers_list. > > > > > > If it is already clarified, then ignore it. > > > > I think it was missing. It IMHO accidentally worked since QLIST_INIT() > > just set the head to NULL and that's what we did when we create the > > IntelIOMMUState object. > > > > And what's worse - I found this approach may not work if we do > > QLIST_INSERT() in the changed() hook, since if we have more than one > > assigned devices we will only register the first one not the rest. A > > better approach may be traversing the vt-d buses via > > IntelIOMMUState.vtd_as_by_busptr. > > > Peter, > > In Oct, I also mailed Aviv about using IntelIOMMUState.vtd_as_by_busptr > when trying to connect the vfio notifiers(map/unmap) and vIOMMU. > However, I reconsidered it later. If I remember correctly, > IntelIOMMUState.vtd_as_by_busptr not only includes vtd_as for assigned > devices, > but also includes virtual devices. When iotlb invalidation comes to vIOMMU, > there > is no indication for which device in iotlb_inv_desc. So still need to have a > list to record > vtd_as which needs to be looped. So I keep silent on it after that thought. > > Now, you mentioned it may not work in multi-assigned scenario. Maybe it's > time to reconsider it again. Hmm, first parameter of vtd_iommu_notify_flag_changed() is memory region, and that's per-device. So current approach should work even with multiple devices. Looks like I made a mistake, sorry. :) Thanks, -- peterx
