On Thu, 28 Feb 2019 15:09:50 +0100 Joerg Roedel <j...@8bytes.org> wrote:
> Hi Jacob, > > On Wed, Feb 27, 2019 at 01:41:29PM -0800, Jacob Pan wrote: > > On Tue, 26 Feb 2019 12:17:43 +0100 > > Joerg Roedel <j...@8bytes.org> wrote: > > > Just trying to understand how to use this API. > > So if we bind the same mm to two different devices, we should get > > two different iommu_sva handle, right? > > I think intel-svm still needs a flag argument for supervisor pasid > > etc. Other than that, I think both interface should work for vt-d. > > I second Jean's question here, is supervisor pasid still needed with > scalable mode? What is the use-case and which mm_struct will be used > for supervisor accesses? > I will delegate this to Ashok. > > Another question is that for nested SVA, we will need to bind guest > > mm. Do you think we should try to reuse this or have it separate? I > > am working on a separate API for now. > > I think a separate API makes more sense. It could be somehow fit into > this as well, but having it separate is cleaner. And we already have > separate API for aux-domains, so this would be just another extension > of the IOMMU-API for using PASIDs. > Agreed. > > > > int iommu_sva_get_pasid(struct iommu_sva *handle); > > If multiple bind to the same mm gets multiple handles, this API > > should retrieve the same pasid for different handle? > > It can return the same handle if we store the pasid in the mm_struct, > for example ... > > Just curious why making the handle private instead of returning the > > pasid value in the handle? > > ... which is also the reason why I prefer the accessor function, it > allows to have the pasid not in the iommu_sva handle, but to retrieve > it from somewhere else (like the mm_struct). make sense, more flexible storage and controlled access too. thanks for explaining. Jacob
