On Thu, 7 Apr 2016 14:28:59 +0200 Eric Auger <eric.au...@linaro.org> wrote:
> Hi Alex, > On 04/07/2016 01:15 AM, Alex Williamson wrote: > > On Mon, 4 Apr 2016 08:06:55 +0000 > > Eric Auger <eric.au...@linaro.org> wrote: > > > >> This series introduces the dma-reserved-iommu api used to: > >> - create/destroy an iova domain dedicated to reserved iova bindings > >> - map/unmap physical addresses onto reserved IOVAs. > >> - unmap and destroy all IOVA reserved bindings > > > > Why are we making the decision to have an unbalanced map vs unmap, we > > can create individual mappings, but only unmap the whole thing and > > start over? That's a strange interface. Thanks, > The "individual" balanced unmap also exists (iommu_put_reserved_iova) > and this is the "normal" path. This happens on msi_domain_deactivate > (and possibly on msi_domain_set_affinity). > > I added iommu_unmap_reserved to handle the case where the userspace > registers a reserved iova domain and fails to unregister it. In that > case one need to handle the cleanup on kernel-side and I chose to > implement this on vfio_iommu_type1 release. All the reserved IOMMU > bindings get destroyed on that event. > > Any advice to handle this situation? If we want to model it similar to regular iommu domains, then iommu_free_reserved_iova_domain() should release all the mappings and destroy the iova domain. Additionally, since the reserved iova domain is just a construct on top of an iommu domain, it should be sufficient to call iommu_domain_free() to also remove the reserved iova domain if one exists. Thanks, Alex
