vfio: selftests: add end of address space DMA map/unmap tests

Add tests which validate dma map/unmap at the end of address space. Add
negative test cases for checking that overflowing ioctl args fail with
the expected errno.

Reviewed-by: David Matlack <dmatlack@google.com>
Signed-off-by: Alex Mastro <amastro@fb.com>
Link: https://lore.kernel.org/r/20251028-fix-unmap-v6-5-2542b96bcc8e@fb.com
Signed-off-by: Alex Williamson <alex@shazbot.org>

diff --git a/tools/testing/selftests/vfio/vfio_dma_mapping_test.c b/tools/testing/selftests/vfio/vfio_dma_mapping_test.c
index a38966e8e5a609158984b0f2f899a1d0d77b40b5..4f1ea79a200c688dea9823b8c5037571de4572a9 100644 (file)
--- a/tools/testing/selftests/vfio/vfio_dma_mapping_test.c
+++ b/tools/testing/selftests/vfio/vfio_dma_mapping_test.c
@@ -112,6 +112,8 @@ FIXTURE_VARIANT_ADD_ALL_IOMMU_MODES(anonymous, 0, 0);
 FIXTURE_VARIANT_ADD_ALL_IOMMU_MODES(anonymous_hugetlb_2mb, SZ_2M, MAP_HUGETLB | MAP_HUGE_2MB);
 FIXTURE_VARIANT_ADD_ALL_IOMMU_MODES(anonymous_hugetlb_1gb, SZ_1G, MAP_HUGETLB | MAP_HUGE_1GB);
 
+#undef FIXTURE_VARIANT_ADD_IOMMU_MODE
+
 FIXTURE_SETUP(vfio_dma_mapping_test)
 {
        self->device = vfio_pci_device_init(device_bdf, variant->iommu_mode);
@@ -195,6 +197,94 @@ unmap:
        ASSERT_TRUE(!munmap(region.vaddr, size));
 }
 
+FIXTURE(vfio_dma_map_limit_test) {
+       struct vfio_pci_device *device;
+       struct vfio_dma_region region;
+       size_t mmap_size;
+};
+
+FIXTURE_VARIANT(vfio_dma_map_limit_test) {
+       const char *iommu_mode;
+};
+
+#define FIXTURE_VARIANT_ADD_IOMMU_MODE(_iommu_mode)                           \
+FIXTURE_VARIANT_ADD(vfio_dma_map_limit_test, _iommu_mode) {                   \
+       .iommu_mode = #_iommu_mode,                                            \
+}
+
+FIXTURE_VARIANT_ADD_ALL_IOMMU_MODES();
+
+#undef FIXTURE_VARIANT_ADD_IOMMU_MODE
+
+FIXTURE_SETUP(vfio_dma_map_limit_test)
+{
+       struct vfio_dma_region *region = &self->region;
+       u64 region_size = getpagesize();
+
+       /*
+        * Over-allocate mmap by double the size to provide enough backing vaddr
+        * for overflow tests
+        */
+       self->mmap_size = 2 * region_size;
+
+       self->device = vfio_pci_device_init(device_bdf, variant->iommu_mode);
+       region->vaddr = mmap(NULL, self->mmap_size, PROT_READ | PROT_WRITE,
+                            MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
+       ASSERT_NE(region->vaddr, MAP_FAILED);
+
+       /* One page prior to the end of address space */
+       region->iova = ~(iova_t)0 & ~(region_size - 1);
+       region->size = region_size;
+}
+
+FIXTURE_TEARDOWN(vfio_dma_map_limit_test)
+{
+       vfio_pci_device_cleanup(self->device);
+       ASSERT_EQ(munmap(self->region.vaddr, self->mmap_size), 0);
+}
+
+TEST_F(vfio_dma_map_limit_test, unmap_range)
+{
+       struct vfio_dma_region *region = &self->region;
+       u64 unmapped;
+       int rc;
+
+       vfio_pci_dma_map(self->device, region);
+       ASSERT_EQ(region->iova, to_iova(self->device, region->vaddr));
+
+       rc = __vfio_pci_dma_unmap(self->device, region, &unmapped);
+       ASSERT_EQ(rc, 0);
+       ASSERT_EQ(unmapped, region->size);
+}
+
+TEST_F(vfio_dma_map_limit_test, unmap_all)
+{
+       struct vfio_dma_region *region = &self->region;
+       u64 unmapped;
+       int rc;
+
+       vfio_pci_dma_map(self->device, region);
+       ASSERT_EQ(region->iova, to_iova(self->device, region->vaddr));
+
+       rc = __vfio_pci_dma_unmap_all(self->device, &unmapped);
+       ASSERT_EQ(rc, 0);
+       ASSERT_EQ(unmapped, region->size);
+}
+
+TEST_F(vfio_dma_map_limit_test, overflow)
+{
+       struct vfio_dma_region *region = &self->region;
+       int rc;
+
+       region->size = self->mmap_size;
+
+       rc = __vfio_pci_dma_map(self->device, region);
+       ASSERT_EQ(rc, -EOVERFLOW);
+
+       rc = __vfio_pci_dma_unmap(self->device, region, NULL);
+       ASSERT_EQ(rc, -EOVERFLOW);
+}
+
 int main(int argc, char *argv[])
 {
        device_bdf = vfio_selftests_get_bdf(&argc, argv);