vfio: selftests: add iova range query helpers

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.

Reviewed-by: David Matlack <dmatlack@google.com>
Tested-by: David Matlack <dmatlack@google.com>
Signed-off-by: Alex Mastro <amastro@fb.com>
Link: https://lore.kernel.org/r/20251111-iova-ranges-v3-1-7960244642c5@fb.com
Signed-off-by: Alex Williamson <alex@shazbot.org>

diff --git a/tools/testing/selftests/vfio/lib/include/vfio_util.h b/tools/testing/selftests/vfio/lib/include/vfio_util.h
index 240409bf5f8ad6201cd0505059bdaf701cf5813a..ef8f06ef0c1390ab0a886706009a281a48b64ef7 100644 (file)
--- 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,
+                                             u32 *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 a381fd253aa7ece000aeda1a26afd3caadb2ddf7..11749348f53fa6cded326932d1cfaf4a93dea997 100644 (file)
--- a/tools/testing/selftests/vfio/lib/vfio_pci_device.c
+++ b/tools/testing/selftests/vfio/lib/vfio_pci_device.c
@@ -29,6 +29,178 @@
        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, u32 bufsz,
+                                                u32 *cap_offset)
+{
+       struct vfio_info_cap_header *hdr;
+
+       if (!*cap_offset)
+               return NULL;
+
+       VFIO_ASSERT_LT(*cap_offset, bufsz);
+       VFIO_ASSERT_GE(bufsz - *cap_offset, sizeof(*hdr));
+
+       hdr = (struct vfio_info_cap_header *)((u8 *)buf + *cap_offset);
+       *cap_offset = hdr->next;
+
+       return hdr;
+}
+
+static struct vfio_info_cap_header *vfio_iommu_info_cap_hdr(struct vfio_iommu_type1_info *info,
+                                                           u16 cap_id)
+{
+       struct vfio_info_cap_header *hdr;
+       u32 cap_offset = info->cap_offset;
+       u32 max_depth;
+       u32 depth = 0;
+
+       if (!(info->flags & VFIO_IOMMU_INFO_CAPS))
+               return NULL;
+
+       if (cap_offset)
+               VFIO_ASSERT_GE(cap_offset, sizeof(*info));
+
+       max_depth = (info->argsz - sizeof(*info)) / sizeof(*hdr);
+
+       while ((hdr = next_cap_hdr(info, info->argsz, &cap_offset))) {
+               depth++;
+               VFIO_ASSERT_LE(depth, max_depth, "Capability chain contains a cycle\n");
+
+               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_get_info(struct vfio_pci_device *device)
+{
+       struct vfio_iommu_type1_info *info;
+
+       info = malloc(sizeof(*info));
+       VFIO_ASSERT_NOT_NULL(info);
+
+       *info = (struct vfio_iommu_type1_info) {
+               .argsz = sizeof(*info),
+       };
+
+       ioctl_assert(device->container_fd, VFIO_IOMMU_GET_INFO, info);
+       VFIO_ASSERT_GE(info->argsz, sizeof(*info));
+
+       info = realloc(info, info->argsz);
+       VFIO_ASSERT_NOT_NULL(info);
+
+       ioctl_assert(device->container_fd, VFIO_IOMMU_GET_INFO, info);
+       VFIO_ASSERT_GE(info->argsz, sizeof(*info));
+
+       return info;
+}
+
+/*
+ * 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,
+                                                      u32 *nranges)
+{
+       struct vfio_iommu_type1_info_cap_iova_range *cap_range;
+       struct vfio_iommu_type1_info *info;
+       struct vfio_info_cap_header *hdr;
+       struct iommu_iova_range *ranges = NULL;
+
+       info = vfio_iommu_get_info(device);
+       hdr = vfio_iommu_info_cap_hdr(info, VFIO_IOMMU_TYPE1_INFO_CAP_IOVA_RANGE);
+       VFIO_ASSERT_NOT_NULL(hdr);
+
+       cap_range = container_of(hdr, struct vfio_iommu_type1_info_cap_iova_range, header);
+       VFIO_ASSERT_GT(cap_range->nr_iovas, 0);
+
+       ranges = calloc(cap_range->nr_iovas, sizeof(*ranges));
+       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(info);
+       return ranges;
+}
+
+/* Return iova ranges of the device's IOAS. Free with free() */
+static struct iommu_iova_range *iommufd_iova_ranges(struct vfio_pci_device *device,
+                                                   u32 *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 = calloc(query.num_iovas, sizeof(*ranges));
+       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;
+}
+
+static int iova_range_comp(const void *a, const void *b)
+{
+       const struct iommu_iova_range *ra = a, *rb = b;
+
+       if (ra->start < rb->start)
+               return -1;
+
+       if (ra->start > rb->start)
+               return 1;
+
+       return 0;
+}
+
+/* Return sorted IOVA ranges of the device. Free with free(). */
+struct iommu_iova_range *vfio_pci_iova_ranges(struct vfio_pci_device *device,
+                                             u32 *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;
+
+       VFIO_ASSERT_GT(*nranges, 0);
+
+       /* Sort and check that ranges are sane and non-overlapping */
+       qsort(ranges, *nranges, sizeof(*ranges), iova_range_comp);
+       VFIO_ASSERT_LT(ranges[0].start, ranges[0].last);
+
+       for (u32 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;