diff options
| author | Michael S. Tsirkin <mst@redhat.com> | 2015-01-15 17:54:13 +0200 |
|---|---|---|
| committer | Rusty Russell <rusty@rustcorp.com.au> | 2015-01-21 16:29:01 +1030 |
| commit | ac399d8f39a860655961660efa5c67e7f3c47912 (patch) | |
| tree | 564273dc5bd0732dfe868860060df59c23860468 | |
| parent | 46506da5f365efe7fe3e4c9da73ab679c0382fac (diff) | |
virtio_pci: add module param to force legacy mode
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 <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
| -rw-r--r-- | drivers/virtio/virtio_pci_common.c | 25 |
1 files changed, 21 insertions, 4 deletions
diff --git a/drivers/virtio/virtio_pci_common.c b/drivers/virtio/virtio_pci_common.c index 8ae34a34f3af..e894eb278d83 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); |