If set, try legacy interface first, modern one if that fails. Useful to work around device/driver bugs, and for compatibility testing.
Signed-off-by: Michael S. Tsirkin <[email protected]> Signed-off-by: Rusty Russell <[email protected]> Tested-by: Gerd Hoffmann <[email protected]> --- drivers/virtio/virtio_pci_common.c | 25 +++++++++++++++++++++---- 1 file changed, 21 insertions(+), 4 deletions(-) diff --git a/drivers/virtio/virtio_pci_common.c b/drivers/virtio/virtio_pci_common.c index 8ae34a3..e894eb2 100644 --- a/drivers/virtio/virtio_pci_common.c +++ b/drivers/virtio/virtio_pci_common.c @@ -19,6 +19,14 @@ #include "virtio_pci_common.h" +static bool force_legacy = false; + +#if IS_ENABLED(CONFIG_VIRTIO_PCI_LEGACY) +module_param(force_legacy, bool, 0444); +MODULE_PARM_DESC(force_legacy, + "Force legacy mode for transitional virtio 1 devices"); +#endif + /* wait for pending irq handlers */ void vp_synchronize_vectors(struct virtio_device *vdev) { @@ -505,11 +513,20 @@ static int virtio_pci_probe(struct pci_dev *pci_dev, if (rc) goto err_request_regions; - rc = virtio_pci_modern_probe(vp_dev); - if (rc == -ENODEV) + if (force_legacy) { rc = virtio_pci_legacy_probe(vp_dev); - if (rc) - goto err_probe; + /* Also try modern mode if we can't map BAR0 (no IO space). */ + if (rc == -ENODEV || rc == -ENOMEM) + rc = virtio_pci_modern_probe(vp_dev); + if (rc) + goto err_probe; + } else { + rc = virtio_pci_modern_probe(vp_dev); + if (rc == -ENODEV) + rc = virtio_pci_legacy_probe(vp_dev); + if (rc) + goto err_probe; + } pci_set_master(pci_dev); -- MST -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
