As Avi pointed out, as we continue to massage the virtio PCI ABI, we can make
things a little more friendly to users by utilizing the PCI revision field to
indicate which version of the ABI we're using. This is a hard ABI version
and incrementing it will cause the guest driver to break.
This is the necessary changes to virtio_pci to support this.
Signed-off-by: Anthony Liguori <aliguori@xxxxxxxxxx>
diff --git a/drivers/virtio/virtio_pci.c b/drivers/virtio/virtio_pci.c
index 192687e..26f787d 100644
--- a/drivers/virtio/virtio_pci.c
+++ b/drivers/virtio/virtio_pci.c
@@ -311,6 +311,12 @@ static int __devinit virtio_pci_probe(struct pci_dev *pci_dev,
if (pci_dev->device < 0x1000 || pci_dev->device > 0x103f)
return -ENODEV;
+ if (pci_dev->revision != VIRTIO_PCI_ABI_VERSION) {
+ printk(KERN_ERR "virtio_pci: expected ABI version %d, got %d\n",
+ VIRTIO_PCI_ABI_VERSION, pci_dev->revision);
+ return -ENODEV;
+ }
+
/* allocate our structure and fill it out */
vp_dev = kzalloc(sizeof(struct virtio_pci_device), GFP_KERNEL);
if (vp_dev == NULL)
diff --git a/include/linux/virtio_pci.h b/include/linux/virtio_pci.h
index 860eb37..b315165 100644
--- a/include/linux/virtio_pci.h
+++ b/include/linux/virtio_pci.h
@@ -52,4 +52,6 @@
* configuration space */
#define VIRTIO_PCI_CONFIG 20
+/* Virtio ABI version, this must match exactly */
+#define VIRTIO_PCI_ABI_VERSION 0
#endif
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