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Commit 0cfd027b authored by Eric Auger's avatar Eric Auger Committed by Alex Williamson
Browse files

vfio_pci: Enable memory accesses before calling pci_map_rom 



pci_map_rom/pci_get_rom_size() performs memory access in the ROM.
In case the Memory Space accesses were disabled, readw() is likely
to trigger a synchronous external abort on some platforms.

In case memory accesses were disabled, re-enable them before the
call and disable them back again just after.

Fixes: 89e1f7d4 ("vfio: Add PCI device driver")
Signed-off-by: default avatarEric Auger <eric.auger@redhat.com>
Suggested-by: default avatarAlex Williamson <alex.williamson@redhat.com>
Signed-off-by: default avatarAlex Williamson <alex.williamson@redhat.com>
parent 51ef3a00

drivers/vfio/pci/vfio_pci.c

+14 −5
Original line number Diff line number Diff line
@@ -759,6 +759,7 @@ static long vfio_pci_ioctl(void *device_data, 
		{

			void __iomem *io;

			size_t size;

			u16 orig_cmd;



			info.offset = VFIO_PCI_INDEX_TO_OFFSET(info.index);

			info.flags = 0;
@@ -774,15 +775,23 @@ static long vfio_pci_ioctl(void *device_data, 
					break;

			}



			/* Is it really there? */

			/*

			 * Is it really there?  Enable memory decode for

			 * implicit access in pci_map_rom().

			 */

			pci_read_config_word(pdev, PCI_COMMAND, &orig_cmd);

			pci_write_config_word(pdev, PCI_COMMAND,

					      orig_cmd | PCI_COMMAND_MEMORY);



			io = pci_map_rom(pdev, &size);

			if (!io || !size) {

			if (io) {

				info.flags = VFIO_REGION_INFO_FLAG_READ;

				pci_unmap_rom(pdev, io);

			} else {

				info.size = 0;

				break;

			}

			pci_unmap_rom(pdev, io);



			info.flags = VFIO_REGION_INFO_FLAG_READ;

			pci_write_config_word(pdev, PCI_COMMAND, orig_cmd);

			break;

		}

		case VFIO_PCI_VGA_REGION_INDEX: