From: Eric Auger eric.auger@redhat.com
[ Upstream commit 0cfd027be1d6def4a462cdc180c055143af24069 ]
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: 89e1f7d4c66d ("vfio: Add PCI device driver") Signed-off-by: Eric Auger eric.auger@redhat.com Suggested-by: Alex Williamson alex.williamson@redhat.com Signed-off-by: Alex Williamson alex.williamson@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/vfio/pci/vfio_pci.c | 19 ++++++++++++++----- 1 file changed, 14 insertions(+), 5 deletions(-)
diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c index 4b62eb3b59233..7a82735d53087 100644 --- a/drivers/vfio/pci/vfio_pci.c +++ b/drivers/vfio/pci/vfio_pci.c @@ -496,6 +496,7 @@ 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; @@ -505,15 +506,23 @@ static long vfio_pci_ioctl(void *device_data, if (!info.size) 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: