blkfront: do not create a PV cdrom device if xen_hvm_guest

It is not possible to unplug emulated cdrom devices, and PV cdroms don't
handle media insert, eject and stream, so we are better off disabling PV
cdroms when running as a Xen HVM guest.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>

diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index 6eb2989a9d0ac587fe6ab8621e00fda287e4ab22..f63ac3d1f8a411b23574fbc221f2d3edd0a12738 100644 (file)
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -738,21 +738,34 @@ static int blkfront_probe(struct xenbus_device *dev,
                }
        }
 
-       /* no unplug has been done: do not hook devices != xen vbds */
-       if (xen_hvm_domain() && (xen_platform_pci_unplug & XEN_UNPLUG_IGNORE)) {
-               int major;
-
-               if (!VDEV_IS_EXTENDED(vdevice))
-                       major = BLKIF_MAJOR(vdevice);
-               else
-                       major = XENVBD_MAJOR;
-
-               if (major != XENVBD_MAJOR) {
-                       printk(KERN_INFO
-                                       "%s: HVM does not support vbd %d as xen block device\n",
-                                       __FUNCTION__, vdevice);
+       if (xen_hvm_domain()) {
+               char *type;
+               int len;
+               /* no unplug has been done: do not hook devices != xen vbds */
+               if (xen_platform_pci_unplug & XEN_UNPLUG_IGNORE) {
+                       int major;
+
+                       if (!VDEV_IS_EXTENDED(vdevice))
+                               major = BLKIF_MAJOR(vdevice);
+                       else
+                               major = XENVBD_MAJOR;
+
+                       if (major != XENVBD_MAJOR) {
+                               printk(KERN_INFO
+                                               "%s: HVM does not support vbd %d as xen block device\n",
+                                               __FUNCTION__, vdevice);
+                               return -ENODEV;
+                       }
+               }
+               /* do not create a PV cdrom device if we are an HVM guest */
+               type = xenbus_read(XBT_NIL, dev->nodename, "device-type", &len);
+               if (IS_ERR(type))
+                       return -ENODEV;
+               if (strncmp(type, "cdrom", 5) == 0) {
+                       kfree(type);
                        return -ENODEV;
                }
+               kfree(type);
        }
        info = kzalloc(sizeof(*info), GFP_KERNEL);
        if (!info) {