> From: Jason Gunthorpe <jgg@xxxxxxxxxx> > Sent: Wednesday, September 22, 2021 2:15 AM > > On Sun, Sep 19, 2021 at 02:38:44PM +0800, Liu Yi L wrote: > > [HACK. will fix in v2] > > > > There are two options to impelement vfio type1v2 mapping semantics in > > /dev/iommu. > > > > One is to duplicate the related code from vfio as the starting point, > > and then merge with vfio type1 at a later time. However > vfio_iommu_type1.c > > has over 3000LOC with ~80% related to dma management logic, including: > > I can't really see a way forward like this. I think some scheme to > move the vfio datastructure is going to be necessary. > > > - the dma map/unmap metadata management > > - page pinning, and related accounting > > - iova range reporting > > - dirty bitmap retrieving > > - dynamic vaddr update, etc. > > All of this needs to be part of the iommufd anyhow.. yes > > > The alternative is to consolidate type1v2 logic in /dev/iommu immediately, > > which requires converting vfio_iommu_type1 to be a shim driver. > > Another choice is the the datastructure coulde move and the two > drivers could share its code and continue to exist more independently > where to put the shared code? btw this is one major open that I plan to discuss in LPC. 😊
