vfio: selftests: replace iova=vaddr with allocated iovas

vfio_dma_mapping_test and vfio_pci_driver_test currently use iova=vaddr
as part of DMA mapping operations. However, not all IOMMUs support the
same virtual address width as the processor. For instance, older Intel
consumer platforms only support 39-bits of IOMMU address space. On such
platforms, using the virtual address as the IOVA fails.

Make the tests more robust by using iova_allocator to vend IOVAs, which
queries legally accessible IOVAs from the underlying IOMMUFD or VFIO
container.

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-v3-4-7960244642c5@fb.com
Signed-off-by: Alex Williamson <alex@shazbot.org>

2 files changed, 12 insertions, 5 deletions

diff --git a/tools/testing/selftests/vfio/vfio_dma_mapping_test.c b/tools/testing/selftests/vfio/vfio_dma_mapping_test.c
index e1374aab96bd..102603d4407d 100644
--- a/tools/testing/selftests/vfio/vfio_dma_mapping_test.c
+++ b/tools/testing/selftests/vfio/vfio_dma_mapping_test.c
@@ -95,6 +95,7 @@ static int iommu_mapping_get(const char *bdf, u64 iova,
 
 FIXTURE(vfio_dma_mapping_test) {
 	struct vfio_pci_device *device;
+	struct iova_allocator *iova_allocator;
 };
 
 FIXTURE_VARIANT(vfio_dma_mapping_test) {
@@ -119,10 +120,12 @@ FIXTURE_VARIANT_ADD_ALL_IOMMU_MODES(anonymous_hugetlb_1gb, SZ_1G, MAP_HUGETLB |
 FIXTURE_SETUP(vfio_dma_mapping_test)
 {
 	self->device = vfio_pci_device_init(device_bdf, variant->iommu_mode);
+	self->iova_allocator = iova_allocator_init(self->device);
 }
 
 FIXTURE_TEARDOWN(vfio_dma_mapping_test)
 {
+	iova_allocator_cleanup(self->iova_allocator);
 	vfio_pci_device_cleanup(self->device);
 }
 
@@ -144,7 +147,7 @@ TEST_F(vfio_dma_mapping_test, dma_map_unmap)
 	else
 		ASSERT_NE(region.vaddr, MAP_FAILED);
 
-	region.iova = (u64)region.vaddr;
+	region.iova = iova_allocator_alloc(self->iova_allocator, size);
 	region.size = size;
 
 	vfio_pci_dma_map(self->device, &region);
diff --git a/tools/testing/selftests/vfio/vfio_pci_driver_test.c b/tools/testing/selftests/vfio/vfio_pci_driver_test.c
index 2dbd70b7db62..f69eec8b928d 100644
--- a/tools/testing/selftests/vfio/vfio_pci_driver_test.c
+++ b/tools/testing/selftests/vfio/vfio_pci_driver_test.c
@@ -19,6 +19,7 @@ static const char *device_bdf;
 } while (0)
 
 static void region_setup(struct vfio_pci_device *device,
+			 struct iova_allocator *iova_allocator,
 			 struct vfio_dma_region *region, u64 size)
 {
 	const int flags = MAP_SHARED | MAP_ANONYMOUS;
@@ -29,7 +30,7 @@ static void region_setup(struct vfio_pci_device *device,
 	VFIO_ASSERT_NE(vaddr, MAP_FAILED);
 
 	region->vaddr = vaddr;
-	region->iova = (u64)vaddr;
+	region->iova = iova_allocator_alloc(iova_allocator, size);
 	region->size = size;
 
 	vfio_pci_dma_map(device, region);
@@ -44,6 +45,7 @@ static void region_teardown(struct vfio_pci_device *device,
 
 FIXTURE(vfio_pci_driver_test) {
 	struct vfio_pci_device *device;
+	struct iova_allocator *iova_allocator;
 	struct vfio_dma_region memcpy_region;
 	void *vaddr;
 	int msi_fd;
@@ -72,14 +74,15 @@ FIXTURE_SETUP(vfio_pci_driver_test)
 	struct vfio_pci_driver *driver;
 
 	self->device = vfio_pci_device_init(device_bdf, variant->iommu_mode);
+	self->iova_allocator = iova_allocator_init(self->device);
 
 	driver = &self->device->driver;
 
-	region_setup(self->device, &self->memcpy_region, SZ_1G);
-	region_setup(self->device, &driver->region, SZ_2M);
+	region_setup(self->device, self->iova_allocator, &self->memcpy_region, SZ_1G);
+	region_setup(self->device, self->iova_allocator, &driver->region, SZ_2M);
 
 	/* Any IOVA that doesn't overlap memcpy_region and driver->region. */
-	self->unmapped_iova = 8UL * SZ_1G;
+	self->unmapped_iova = iova_allocator_alloc(self->iova_allocator, SZ_1G);
 
 	vfio_pci_driver_init(self->device);
 	self->msi_fd = self->device->msi_eventfds[driver->msi];
@@ -108,6 +111,7 @@ FIXTURE_TEARDOWN(vfio_pci_driver_test)
 	region_teardown(self->device, &self->memcpy_region);
 	region_teardown(self->device, &driver->region);
 
+	iova_allocator_cleanup(self->iova_allocator);
 	vfio_pci_device_cleanup(self->device);
 }