diff --git a/sys/dev/xen/blkfront/blkfront.c b/sys/dev/xen/blkfront/blkfront.c index feb79a1eb86c..92b5f3542819 100644 --- a/sys/dev/xen/blkfront/blkfront.c +++ b/sys/dev/xen/blkfront/blkfront.c @@ -1381,14 +1381,42 @@ xbd_closing(device_t dev) static int xbd_probe(device_t dev) { + if (strcmp(xenbus_get_type(dev), "vbd") != 0) + return (ENXIO); - if (!strcmp(xenbus_get_type(dev), "vbd")) { - device_set_desc(dev, "Virtual Block Device"); - device_quiet(dev); - return (0); + if (xen_hvm_domain()) { + int error; + char *type; + + /* + * When running in an HVM domain, IDE disk emulation is + * disabled early in boot so that native drivers will + * not see emulated hardware. However, CDROM device + * emulation cannot be disabled. + * + * Through use of FreeBSD's vm_guest and xen_hvm_domain() + * APIs, we could modify the native CDROM driver to fail its + * probe when running under Xen. Unfortunatlely, the PV + * CDROM support in XenServer (up through at least version + * 6.2) isn't functional, so we instead rely on the emulated + * CDROM instance, and fail to attach the PV one here in + * the blkfront driver. + */ + error = xs_read(XST_NIL, xenbus_get_node(dev), + "device-type", NULL, (void **) &type); + if (error) + return (ENXIO); + + if (strncmp(type, "cdrom", 5) == 0) { + free(type, M_XENSTORE); + return (ENXIO); + } + free(type, M_XENSTORE); } - return (ENXIO); + device_set_desc(dev, "Virtual Block Device"); + device_quiet(dev); + return (0); } /*