vfio/pci: Bypass IGD init in case of -ENODEV

[ Upstream commit e4eccb853664de7bcf9518fb658f35e748bf1f68 ]

Bypass the IGD initialization when -ENODEV returns,
that should be the case if opregion is not available for IGD
or within discrete graphics device's option ROM,
or host/lpc bridge is not found.

Then use of -ENODEV here means no special device resources found
which needs special care for VFIO, but we still allow other normal
device resource access.

Cc: Zhenyu Wang <zhenyuw@linux.intel.com>
Cc: Xiong Zhang <xiong.y.zhang@intel.com>
Cc: Hang Yuan <hang.yuan@linux.intel.com>
Cc: Stuart Summers <stuart.summers@intel.com>
Signed-off-by: Fred Gao <fred.gao@intel.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index 1ab1f5cda4ac27431f5a512c60598560e95137d1..bfdc010a6b043e1102ee19b7e9bfafbaf938dcb3 100644 (file)
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -385,7 +385,7 @@ static int vfio_pci_enable(struct vfio_pci_device *vdev)
            pdev->vendor == PCI_VENDOR_ID_INTEL &&
            IS_ENABLED(CONFIG_VFIO_PCI_IGD)) {
                ret = vfio_pci_igd_init(vdev);
-               if (ret) {
+               if (ret && ret != -ENODEV) {
                        pci_warn(pdev, "Failed to setup Intel IGD regions\n");
                        goto disable_exit;
                }