Add struct iova_allocator, which gives tests a convenient way to generate legally-accessible IOVAs to map. This allocator traverses the sorted available IOVA ranges linearly, requires power-of-two size allocations, and does not support freeing iova allocations. The assumption is that tests are not IOVA space-bounded, and will not need to recycle IOVAs.
This is based on Alex Williamson's patch series for adding an IOVA allocator [1].
[1] https://lore.kernel.org/all/20251108212954.26477-1-alex@shazbot.org/
Reviewed-by: David Matlack dmatlack@google.com Tested-by: David Matlack dmatlack@google.com Signed-off-by: Alex Mastro amastro@fb.com --- .../testing/selftests/vfio/lib/include/vfio_util.h | 11 ++++ tools/testing/selftests/vfio/lib/vfio_pci_device.c | 74 +++++++++++++++++++++- 2 files changed, 84 insertions(+), 1 deletion(-)
diff --git a/tools/testing/selftests/vfio/lib/include/vfio_util.h b/tools/testing/selftests/vfio/lib/include/vfio_util.h index ef8f06ef0c13..69ec0c856481 100644 --- a/tools/testing/selftests/vfio/lib/include/vfio_util.h +++ b/tools/testing/selftests/vfio/lib/include/vfio_util.h @@ -188,6 +188,13 @@ struct vfio_pci_device { struct vfio_pci_driver driver; };
+struct iova_allocator { + struct iommu_iova_range *ranges; + u32 nranges; + u32 range_idx; + u64 range_offset; +}; + /* * Return the BDF string of the device that the test should use. * @@ -212,6 +219,10 @@ void vfio_pci_device_reset(struct vfio_pci_device *device); struct iommu_iova_range *vfio_pci_iova_ranges(struct vfio_pci_device *device, u32 *nranges);
+struct iova_allocator *iova_allocator_init(struct vfio_pci_device *device); +void iova_allocator_cleanup(struct iova_allocator *allocator); +iova_t iova_allocator_alloc(struct iova_allocator *allocator, size_t size); + int __vfio_pci_dma_map(struct vfio_pci_device *device, struct vfio_dma_region *region); int __vfio_pci_dma_unmap(struct vfio_pci_device *device, diff --git a/tools/testing/selftests/vfio/lib/vfio_pci_device.c b/tools/testing/selftests/vfio/lib/vfio_pci_device.c index 11749348f53f..b479a359da12 100644 --- a/tools/testing/selftests/vfio/lib/vfio_pci_device.c +++ b/tools/testing/selftests/vfio/lib/vfio_pci_device.c @@ -12,11 +12,12 @@ #include <sys/mman.h>
#include <uapi/linux/types.h> +#include <linux/iommufd.h> #include <linux/limits.h> #include <linux/mman.h> +#include <linux/overflow.h> #include <linux/types.h> #include <linux/vfio.h> -#include <linux/iommufd.h>
#include "../../../kselftest.h" #include <vfio_util.h> @@ -201,6 +202,77 @@ struct iommu_iova_range *vfio_pci_iova_ranges(struct vfio_pci_device *device, return ranges; }
+struct iova_allocator *iova_allocator_init(struct vfio_pci_device *device) +{ + struct iova_allocator *allocator; + struct iommu_iova_range *ranges; + u32 nranges; + + ranges = vfio_pci_iova_ranges(device, &nranges); + VFIO_ASSERT_NOT_NULL(ranges); + + allocator = malloc(sizeof(*allocator)); + VFIO_ASSERT_NOT_NULL(allocator); + + *allocator = (struct iova_allocator){ + .ranges = ranges, + .nranges = nranges, + .range_idx = 0, + .range_offset = 0, + }; + + return allocator; +} + +void iova_allocator_cleanup(struct iova_allocator *allocator) +{ + free(allocator->ranges); + free(allocator); +} + +iova_t iova_allocator_alloc(struct iova_allocator *allocator, size_t size) +{ + VFIO_ASSERT_GT(size, 0, "Invalid size arg, zero\n"); + VFIO_ASSERT_EQ(size & (size - 1), 0, "Invalid size arg, non-power-of-2\n"); + + for (;;) { + struct iommu_iova_range *range; + iova_t iova, last; + + VFIO_ASSERT_LT(allocator->range_idx, allocator->nranges, + "IOVA allocator out of space\n"); + + range = &allocator->ranges[allocator->range_idx]; + iova = range->start + allocator->range_offset; + + /* Check for sufficient space at the current offset */ + if (check_add_overflow(iova, size - 1, &last) || + last > range->last) + goto next_range; + + /* Align iova to size */ + iova = last & ~(size - 1); + + /* Check for sufficient space at the aligned iova */ + if (check_add_overflow(iova, size - 1, &last) || + last > range->last) + goto next_range; + + if (last == range->last) { + allocator->range_idx++; + allocator->range_offset = 0; + } else { + allocator->range_offset = last - range->start + 1; + } + + return iova; + +next_range: + allocator->range_idx++; + allocator->range_offset = 0; + } +} + iova_t __to_iova(struct vfio_pci_device *device, void *vaddr) { struct vfio_dma_region *region;