On Fri, Oct 13, 2023 at 06:10:04PM +0100, Joao Martins wrote: > On 13/10/2023 17:00, Joao Martins wrote: > > On 13/10/2023 16:48, Jason Gunthorpe wrote: > >> On Sat, Sep 23, 2023 at 02:24:54AM +0100, Joao Martins wrote: > >>> Both VFIO and IOMMUFD will need iova bitmap for storing dirties and walking > >>> the user bitmaps, so move to the common dependency into IOMMU core. IOMMUFD > >>> can't exactly host it given that VFIO dirty tracking can be used without > >>> IOMMUFD. > >> > >> Hum, this seems strange. Why not just make those VFIO drivers depends > >> on iommufd? That seems harmless to me. > >> > > > > IF you and Alex are OK with it then I can move to IOMMUFD. > > > >> However, I think the real issue is that iommu drivers need to use this > >> API too for their part? > >> > > > > Exactly. > > > > My other concern into moving to IOMMUFD instead of core was VFIO_IOMMU_TYPE1, > and if we always make it depend on IOMMUFD then we can't have what is today > something supported because of VFIO_IOMMU_TYPE1 stuff with migration drivers > (i.e. vfio-iommu-type1 with the live migration stuff). I plan to remove the live migration stuff from vfio-iommu-type1, it is all dead code now. > But if it's exists an IOMMUFD_DRIVER kconfig, then VFIO_CONTAINER can instead > select the IOMMUFD_DRIVER alone so long as CONFIG_IOMMUFD isn't required? I am > essentially talking about: Not VFIO_CONTAINER, the dirty tracking code is in vfio_main: vfio_main.c:#include <linux/iova_bitmap.h> vfio_main.c:static int vfio_device_log_read_and_clear(struct iova_bitmap *iter, vfio_main.c: struct iova_bitmap *iter; vfio_main.c: iter = iova_bitmap_alloc(report.iova, report.length, vfio_main.c: ret = iova_bitmap_for_each(iter, device, vfio_main.c: iova_bitmap_free(iter); And in various vfio device drivers. So the various drivers can select IOMMUFD_DRIVER And the core code should just gain a if (!IS_SUPPORTED(CONFIG_IOMMUFD_DRIVER)) return -EOPNOTSUPP On the two functions grep found above so the compiler eliminates all the symbols. No kconfig needed. Jason
