vfio: selftests: Eliminate INVALID_IOVA

Eliminate INVALID_IOVA as there are platforms where UINT64_MAX is a
valid iova.

Reviewed-by: Alex Mastro <amastro@fb.com>
Tested-by: Alex Mastro <amastro@fb.com>
Reviewed-by: Raghavendra Rao Ananta <rananta@google.com>
Signed-off-by: David Matlack <dmatlack@google.com>
Link: https://lore.kernel.org/r/20251126231733.3302983-18-dmatlack@google.com
Signed-off-by: Alex Williamson <alex@shazbot.org>

Author: dmatlack

tools/testing/selftests/vfio/lib/include/libvfio/iommu.h

@@ -8,7 +8,6 @@
 #include <libvfio/assert.h>
 
 typedef u64 iova_t;
-#define INVALID_IOVA UINT64_MAX
 
 struct iommu_mode {
 	const char *name;
@@ -57,7 +56,7 @@ static inline void iommu_unmap_all(struct iommu *iommu)
 	VFIO_ASSERT_EQ(__iommu_unmap_all(iommu, NULL), 0);
 }
 
-iova_t __iommu_hva2iova(struct iommu *iommu, void *vaddr);
+int __iommu_hva2iova(struct iommu *iommu, void *vaddr, iova_t *iova);
 iova_t iommu_hva2iova(struct iommu *iommu, void *vaddr);
 
 struct iommu_iova_range *iommu_iova_ranges(struct iommu *iommu, u32 *nranges);

tools/testing/selftests/vfio/lib/include/libvfio/vfio_pci_device.h

@@ -103,9 +103,9 @@ static inline void vfio_pci_msix_disable(struct vfio_pci_device *device)
 	vfio_pci_irq_disable(device, VFIO_PCI_MSIX_IRQ_INDEX);
 }
 
-static inline iova_t __to_iova(struct vfio_pci_device *device, void *vaddr)
+static inline int __to_iova(struct vfio_pci_device *device, void *vaddr, iova_t *iova)
 {
-	return __iommu_hva2iova(device->iommu, vaddr);
+	return __iommu_hva2iova(device->iommu, vaddr, iova);
 }
 
 static inline iova_t to_iova(struct vfio_pci_device *device, void *vaddr)

tools/testing/selftests/vfio/lib/iommu.c

@@ -67,7 +67,7 @@ static const struct iommu_mode *lookup_iommu_mode(const char *iommu_mode)
 	VFIO_FAIL("Unrecognized IOMMU mode: %s\n", iommu_mode);
 }
 
-iova_t __iommu_hva2iova(struct iommu *iommu, void *vaddr)
+int __iommu_hva2iova(struct iommu *iommu, void *vaddr, iova_t *iova)
 {
 	struct dma_region *region;
 
@@ -78,18 +78,22 @@ iova_t __iommu_hva2iova(struct iommu *iommu, void *vaddr)
 		if (vaddr >= region->vaddr + region->size)
 			continue;
 
-		return region->iova + (vaddr - region->vaddr);
+		if (iova)
+			*iova = region->iova + (vaddr - region->vaddr);
+
+		return 0;
 	}
 
-	return INVALID_IOVA;
+	return -ENOENT;
 }
 
 iova_t iommu_hva2iova(struct iommu *iommu, void *vaddr)
 {
 	iova_t iova;
+	int ret;
 
-	iova = __iommu_hva2iova(iommu, vaddr);
-	VFIO_ASSERT_NE(iova, INVALID_IOVA, "%p is not mapped into IOMMU\n", vaddr);
+	ret = __iommu_hva2iova(iommu, vaddr, &iova);
+	VFIO_ASSERT_EQ(ret, 0, "%p is not mapped into the iommu\n", vaddr);
 
 	return iova;
 }

tools/testing/selftests/vfio/vfio_dma_mapping_test.c

@@ -199,7 +199,7 @@ TEST_F(vfio_dma_mapping_test, dma_map_unmap)
 	ASSERT_EQ(rc, 0);
 	ASSERT_EQ(unmapped, region.size);
 	printf("Unmapped IOVA 0x%lx\n", region.iova);
-	ASSERT_EQ(INVALID_IOVA, __to_iova(self->device, region.vaddr));
+	ASSERT_NE(0, __to_iova(self->device, region.vaddr, NULL));
 	ASSERT_NE(0, iommu_mapping_get(device_bdf, region.iova, &mapping));
 
 	ASSERT_TRUE(!munmap(region.vaddr, size));