On Mon, Nov 10, 2025 at 10:03:54PM +0000, David Matlack wrote:
On 2025-11-10 01:10 PM, Alex Mastro wrote:
+/*
- 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;
nit: Maybe name this variable `info` here and in vfio_iommu_info_buf() and vfio_iommu_info_cap_hdr()? It is not an opaque buffer.
- struct vfio_info_cap_header *hdr;
- struct iommu_iova_range *ranges = NULL;
- buf = vfio_iommu_info_buf(device);
nit: How about naming this vfio_iommu_get_info() since it actually fetches the info from VFIO? (It doesn't just allocate a buffer.)
- VFIO_ASSERT_NOT_NULL(buf);
This assert is unnecessary.
- hdr = vfio_iommu_info_cap_hdr(buf, VFIO_IOMMU_TYPE1_INFO_CAP_IOVA_RANGE);
- if (!hdr)
goto free_buf;Is this to account for running on old versions of VFIO? Or are there some scenarios when VFIO can't report the list of IOVA ranges?
I wanted to avoid being overly assertive in this low-level helper function, mostly out of ignorance about where/in which system states this capability may not be reported.
- 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));
- 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));
- 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)nit: Both iommufd and VFIO represent the number of IOVA ranges as a u32. Perhaps we should do the same in VFIO selftests?
Thanks David. All suggestions SGTM -- will roll into v2.