On Mon, 10 Nov 2025 13:10:41 -0800 Alex Mastro <[email protected]> wrote:
> VFIO selftests need to map IOVAs from legally accessible ranges, which > could vary between hardware. Tests in vfio_dma_mapping_test.c are making > excessively strong assumptions about which IOVAs can be mapped. > > Add vfio_iommu_iova_ranges(), which queries IOVA ranges from the > IOMMUFD or VFIO container associated with the device. The queried ranges > are normalized to IOMMUFD's iommu_iova_range representation so that > handling of IOVA ranges up the stack can be implementation-agnostic. > iommu_iova_range and vfio_iova_range are equivalent, so bias to using the > new interface's struct. > > Query IOMMUFD's ranges with IOMMU_IOAS_IOVA_RANGES. > Query VFIO container's ranges with VFIO_IOMMU_GET_INFO and > VFIO_IOMMU_TYPE1_INFO_CAP_IOVA_RANGE. > > The underlying vfio_iommu_type1_info buffer-related functionality has > been kept generic so the same helpers can be used to query other > capability chain information, if needed. > > Signed-off-by: Alex Mastro <[email protected]> > --- > .../testing/selftests/vfio/lib/include/vfio_util.h | 8 +- > tools/testing/selftests/vfio/lib/vfio_pci_device.c | 161 > +++++++++++++++++++++ > 2 files changed, 168 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 240409bf5f8a..fb5efec52316 100644 > --- a/tools/testing/selftests/vfio/lib/include/vfio_util.h > +++ b/tools/testing/selftests/vfio/lib/include/vfio_util.h > @@ -4,9 +4,12 @@ > > #include <fcntl.h> > #include <string.h> > -#include <linux/vfio.h> > + > +#include <uapi/linux/types.h> > +#include <linux/iommufd.h> > #include <linux/list.h> > #include <linux/pci_regs.h> > +#include <linux/vfio.h> > > #include "../../../kselftest.h" > > @@ -206,6 +209,9 @@ struct vfio_pci_device *vfio_pci_device_init(const char > *bdf, const char *iommu_ > void vfio_pci_device_cleanup(struct vfio_pci_device *device); > 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 __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 a381fd253aa7..6bedbe65f0a1 100644 > --- a/tools/testing/selftests/vfio/lib/vfio_pci_device.c > +++ b/tools/testing/selftests/vfio/lib/vfio_pci_device.c > @@ -29,6 +29,167 @@ > VFIO_ASSERT_EQ(__ret, 0, "ioctl(%s, %s, %s) returned %d\n", #_fd, #_op, > #_arg, __ret); \ > } while (0) > > +static struct vfio_info_cap_header *next_cap_hdr(void *buf, size_t bufsz, > + size_t *cap_offset) > +{ > + struct vfio_info_cap_header *hdr; > + > + if (!*cap_offset) > + return NULL; > + > + /* Cap offset must be in bounds */ > + VFIO_ASSERT_LT(*cap_offset, bufsz); > + /* There must be enough remaining space to contain the header */ > + VFIO_ASSERT_GE(bufsz - *cap_offset, sizeof(*hdr)); > + > + hdr = (struct vfio_info_cap_header *)((u8 *)buf + *cap_offset); > + > + /* If there is a next, offset must increase by at least the header size > */ > + if (hdr->next) { > + VFIO_ASSERT_GT(hdr->next, *cap_offset); > + VFIO_ASSERT_GE(hdr->next - *cap_offset, sizeof(*hdr)); > + } > + > + *cap_offset = hdr->next; > + > + return hdr; > +} > + > +static struct vfio_info_cap_header *vfio_iommu_info_cap_hdr(struct > vfio_iommu_type1_info *buf, > + u16 cap_id) > +{ > + struct vfio_info_cap_header *hdr; > + size_t cap_offset = buf->cap_offset; > + > + if (!(buf->flags & VFIO_IOMMU_INFO_CAPS)) > + return NULL; > + > + if (cap_offset) > + VFIO_ASSERT_GE(cap_offset, sizeof(struct > vfio_iommu_type1_info)); > + > + while ((hdr = next_cap_hdr(buf, buf->argsz, &cap_offset))) { > + if (hdr->id == cap_id) > + return hdr; > + } > + > + return NULL; > +} > + > +/* Return buffer including capability chain, if present. Free with free() */ > +static struct vfio_iommu_type1_info *vfio_iommu_info_buf(struct > vfio_pci_device *device) > +{ > + struct vfio_iommu_type1_info *buf; > + > + buf = malloc(sizeof(*buf)); > + VFIO_ASSERT_NOT_NULL(buf); > + > + *buf = (struct vfio_iommu_type1_info) { > + .argsz = sizeof(*buf), > + }; > + > + ioctl_assert(device->container_fd, VFIO_IOMMU_GET_INFO, buf); > + > + buf = realloc(buf, buf->argsz); > + VFIO_ASSERT_NOT_NULL(buf); > + > + ioctl_assert(device->container_fd, VFIO_IOMMU_GET_INFO, buf); > + > + return buf; > +} > + > +/* > + * Return iova ranges for the device's container. Normalize vfio_iommu_type1 > to > + * report iommufd's iommu_iova_range. Free with free(). > + */ > +static struct iommu_iova_range *vfio_iommu_iova_ranges(struct > vfio_pci_device *device, > + size_t *nranges) > +{ > + struct vfio_iommu_type1_info_cap_iova_range *cap_range; > + struct vfio_iommu_type1_info *buf; > + struct vfio_info_cap_header *hdr; > + struct iommu_iova_range *ranges = NULL; > + > + buf = vfio_iommu_info_buf(device); > + VFIO_ASSERT_NOT_NULL(buf); > + > + hdr = vfio_iommu_info_cap_hdr(buf, > VFIO_IOMMU_TYPE1_INFO_CAP_IOVA_RANGE); > + if (!hdr) > + goto free_buf; > + > + cap_range = container_of(hdr, struct > vfio_iommu_type1_info_cap_iova_range, header); > + if (!cap_range->nr_iovas) > + goto free_buf; > + > + ranges = malloc(cap_range->nr_iovas * sizeof(*ranges)); Natural calloc() use case. > + VFIO_ASSERT_NOT_NULL(ranges); > + > + for (u32 i = 0; i < cap_range->nr_iovas; i++) { > + ranges[i] = (struct iommu_iova_range){ > + .start = cap_range->iova_ranges[i].start, > + .last = cap_range->iova_ranges[i].end, > + }; > + } > + > + *nranges = cap_range->nr_iovas; > + > +free_buf: > + free(buf); > + return ranges; > +} > + > +/* Return iova ranges of the device's IOAS. Free with free() */ > +struct iommu_iova_range *iommufd_iova_ranges(struct vfio_pci_device *device, > + size_t *nranges) > +{ > + struct iommu_iova_range *ranges; > + int ret; > + > + struct iommu_ioas_iova_ranges query = { > + .size = sizeof(query), > + .ioas_id = device->ioas_id, > + }; > + > + ret = ioctl(device->iommufd, IOMMU_IOAS_IOVA_RANGES, &query); > + VFIO_ASSERT_EQ(ret, -1); > + VFIO_ASSERT_EQ(errno, EMSGSIZE); > + VFIO_ASSERT_GT(query.num_iovas, 0); > + > + ranges = malloc(query.num_iovas * sizeof(*ranges)); Same. > + VFIO_ASSERT_NOT_NULL(ranges); > + > + query.allowed_iovas = (uintptr_t)ranges; > + > + ioctl_assert(device->iommufd, IOMMU_IOAS_IOVA_RANGES, &query); > + *nranges = query.num_iovas; > + > + return ranges; > +} > + > +struct iommu_iova_range *vfio_pci_iova_ranges(struct vfio_pci_device *device, > + size_t *nranges) > +{ > + struct iommu_iova_range *ranges; > + > + if (device->iommufd) > + ranges = iommufd_iova_ranges(device, nranges); > + else > + ranges = vfio_iommu_iova_ranges(device, nranges); > + > + if (!ranges) > + return NULL; > + > + /* ranges should be valid, ascending, and non-overlapping */ I don't recall that ranges are required to be in any particular order. Thanks, Alex > + VFIO_ASSERT_GT(*nranges, 0); > + VFIO_ASSERT_LT(ranges[0].start, ranges[0].last); > + > + for (size_t i = 1; i < *nranges; i++) { > + VFIO_ASSERT_LT(ranges[i].start, ranges[i].last); > + VFIO_ASSERT_LT(ranges[i - 1].last, ranges[i].start); > + } > + > + return ranges; > +} > + > iova_t __to_iova(struct vfio_pci_device *device, void *vaddr) > { > struct vfio_dma_region *region; >
