vfio: fix truncated BAR offset for 32-bit

[ upstream commit 8108393 ]

When 32-bit application is built on 64-bit system it is possible that
the offset of the resource is outside of the 32-bit value.

The problem with the unsigned long is, that it is 32-bit and not 64-bit
when using armhf compiler. Although the system is returning u64 value,
we are losing it's value if it's higher than 32-bit in the conversion
process. It can further cause mmap to fail due to offset being 0 or to
map not intended memory region.

To make it more portable, the uint64_t value is now being used for
storing offset instead of unsigned long. The size of being 32-bit seems
to be fine as the 32-bit application won't be able to access bigger
memory and it is further converted to size_t anyway. But for better
readability and to be consistent, it's type was changed to size_t as
well.

Fixes: 0205f87 ("vfio: fix overflow of BAR region offset and size")

Signed-off-by: Michal Krawczyk <mk@semihalf.com>
Acked-by: Anatoly Burakov <anatoly.burakov@intel.com>

drivers/bus/pci/linux/pci_vfio.c

@@ -451,7 +451,8 @@ pci_vfio_mmap_bar(int vfio_dev_fd, struct mapped_pci_resource *vfio_res,
 		int bar_index, int additional_flags)
 {
 	struct memreg {
-		unsigned long offset, size;
+		uint64_t offset;
+		size_t   size;
 	} memreg[2] = {};
 	void *bar_addr;
 	struct pci_msix_table *msix_table = &vfio_res->msix_table;
@@ -487,7 +488,8 @@ pci_vfio_mmap_bar(int vfio_dev_fd, struct mapped_pci_resource *vfio_res,
 		RTE_LOG(DEBUG, EAL,
 			"Trying to map BAR%d that contains the MSI-X "
 			"table. Trying offsets: "
-			"0x%04lx:0x%04lx, 0x%04lx:0x%04lx\n", bar_index,
+			"0x%04" PRIx64 ":0x%04zx, 0x%04" PRIx64 ":0x%04zx\n",
+			bar_index,
 			memreg[0].offset, memreg[0].size,
 			memreg[1].offset, memreg[1].size);
 	} else {
@@ -512,8 +514,8 @@ pci_vfio_mmap_bar(int vfio_dev_fd, struct mapped_pci_resource *vfio_res,
 		if (map_addr != MAP_FAILED
 			&& memreg[1].offset && memreg[1].size) {
 			void *second_addr = RTE_PTR_ADD(bar_addr,
-							memreg[1].offset -
-							(uintptr_t)bar->offset);
+						(uintptr_t)(memreg[1].offset -
+						bar->offset));
 			map_addr = pci_map_resource(second_addr,
 							vfio_dev_fd,
 							memreg[1].offset,