On 13/10/2023 21:41, Alex Williamson wrote: > On Fri, 13 Oct 2023 18:23:09 +0100 > Joao Martins <joao.m.martins@xxxxxxxxxx> wrote: > >> On 13/10/2023 18:16, Jason Gunthorpe wrote: >>> 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: >>>> 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 >>> >> >> It isn't so much that type1 requires IOMMUFD, but more that it is used together >> with the core code that allows the vfio drivers to do migration. So the concern >> is if we make VFIO core depend on IOMMU that we prevent >> VFIO_CONTAINER/VFIO_GROUP to not be selected. My kconfig read was that we either >> select VFIO_GROUP or VFIO_DEVICE_CDEV but not both > > That's not true. We can have both. In fact we rely on having both to > support a smooth transition to the cdev interface. Thanks, On a triple look, mixed defaults[0] vs manual config: having IOMMUFD=y|m today it won't select VFIO_CONTAINER, nobody stops one from actually selecting it both. Unless I missed something [0] Ref: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/tree/drivers/vfio/Kconfig menuconfig VFIO [...] select VFIO_GROUP if SPAPR_TCE_IOMMU || IOMMUFD=n select VFIO_DEVICE_CDEV if !VFIO_GROUP select VFIO_CONTAINER if IOMMUFD=n [...] if VFIO config VFIO_DEVICE_CDEV [...] depends on IOMMUFD && !SPAPR_TCE_IOMMU default !VFIO_GROUP [...] config VFIO_GROUP default y [...] config VFIO_CONTAINER [...] select VFIO_IOMMU_TYPE1 if MMU && (X86 || S390 || ARM || ARM64) depends on VFIO_GROUP default y
