Hi, I made the patch that corrected the following problem. It is that when I executed the "virsh detach-disk" command on Xen3.3.1, Libvirt could not detach tap device and output the following error message. # virsh detach-disk Fedora xvdd libvir: Xen Daemon error : POST operation failed: xend_post: error from xen daemon: (xend.err 'Device 51760 not connected') The cause of this problem is incompatible of Xen3.3.0 and Xen3.3.1. I think Xen specific was changed by the following patch. http://xenbits.xensource.com/xen-3.3-testing.hg?rev/e0e17216ba70 If you have any comments, please suggest me. Signed-off-by: Tomohiro Takahashi <takatom@jp.fujitsu.com> Thanks, Tomohiro Takahashi diff -uNrp libvirt.orig/src/xend_internal.c libvirt/src/xend_internal.c --- libvirt.orig/src/xend_internal.c 2009-02-14 03:23:23.000000000 +0900 +++ libvirt/src/xend_internal.c 2009-03-09 12:28:48.000000000 +0900 @@ -5566,7 +5566,11 @@ virDomainXMLDevID(virDomainPtr domain, char *xref; if (dev->type == VIR_DOMAIN_DEVICE_DISK) { - strcpy(class, "vbd"); + if (!(strcmp(dev->data.disk->driverName, "tap"))) { + strcpy(class, "tap"); + } else { + strcpy(class, "vbd"); + } if (dev->data.disk->dst == NULL) return -1; xenUnifiedLock(priv);