On Mon, 10 Nov 2025 13:10:43 -0800 Alex Mastro <[email protected]> wrote:
> Add struct iova_allocator, which gives tests a convenient way to generate > legally-accessible IOVAs to map. > > This is based on Alex Williamson's patch series for adding an IOVA > allocator [1]. > > [1] https://lore.kernel.org/all/[email protected]/ > > Signed-off-by: Alex Mastro <[email protected]> > --- > .../testing/selftests/vfio/lib/include/vfio_util.h | 14 +++++ > tools/testing/selftests/vfio/lib/vfio_pci_device.c | 65 > +++++++++++++++++++++- > 2 files changed, 78 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 fb5efec52316..bb1e7d39dfb9 100644 > --- a/tools/testing/selftests/vfio/lib/include/vfio_util.h > +++ b/tools/testing/selftests/vfio/lib/include/vfio_util.h > @@ -13,6 +13,8 @@ > > #include "../../../kselftest.h" > > +#define ALIGN(x, a) (((x) + (a - 1)) & (~((a) - 1))) > + > #define VFIO_LOG_AND_EXIT(...) do { \ > fprintf(stderr, " " __VA_ARGS__); \ > fprintf(stderr, "\n"); \ > @@ -188,6 +190,13 @@ struct vfio_pci_device { > struct vfio_pci_driver driver; > }; > > +struct iova_allocator { > + struct iommu_iova_range *ranges; > + size_t nranges; > + size_t range_idx; > + iova_t iova_next; > +}; > + > /* > * Return the BDF string of the device that the test should use. > * > @@ -212,6 +221,11 @@ void vfio_pci_device_reset(struct vfio_pci_device > *device); > struct iommu_iova_range *vfio_pci_iova_ranges(struct vfio_pci_device *device, > size_t *nranges); > > +int iova_allocator_init(struct vfio_pci_device *device, > + struct iova_allocator *allocator); > +void iova_allocator_deinit(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 6bedbe65f0a1..a634feb1d378 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> > @@ -190,6 +191,68 @@ struct iommu_iova_range *vfio_pci_iova_ranges(struct > vfio_pci_device *device, > return ranges; > } > > +int iova_allocator_init(struct vfio_pci_device *device, > + struct iova_allocator *allocator) > +{ > + struct iommu_iova_range *ranges; > + size_t nranges; > + > + memset(allocator, 0, sizeof(*allocator)); > + > + ranges = vfio_pci_iova_ranges(device, &nranges); > + if (!ranges) > + return -ENOENT; > + > + *allocator = (struct iova_allocator){ > + .ranges = ranges, > + .nranges = nranges, > + .range_idx = 0, > + .iova_next = 0, iova_next needs to be initialized from ranges[0].start. Thanks, Alex > + }; > + > + return 0; > +} > + > +void iova_allocator_deinit(struct iova_allocator *allocator) > +{ > + free(allocator->ranges); > +} > + > +iova_t iova_allocator_alloc(struct iova_allocator *allocator, size_t size) > +{ > + int idx = allocator->range_idx; > + struct iommu_iova_range *range = &allocator->ranges[idx]; > + > + VFIO_ASSERT_LT(idx, allocator->nranges, "IOVA allocator out of > space\n"); > + 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 (;;) { > + iova_t iova, last; > + > + iova = ALIGN(allocator->iova_next, size); > + > + if (iova < allocator->iova_next || iova > range->last || > + check_add_overflow(iova, size - 1, &last) || > + last > range->last) { > + allocator->range_idx = ++idx; > + VFIO_ASSERT_LT(idx, allocator->nranges, > + "Out of ranges for allocation\n"); > + allocator->iova_next = (++range)->start; > + continue; > + } > + > + if (check_add_overflow(last, (iova_t)1, &allocator->iova_next) > || > + allocator->iova_next > range->last) { > + allocator->range_idx = ++idx; > + if (idx < allocator->nranges) > + allocator->iova_next = (++range)->start; > + } > + > + return iova; > + } > +} > + > iova_t __to_iova(struct vfio_pci_device *device, void *vaddr) > { > struct vfio_dma_region *region; >
