while trying a live migration for KVM with libvirt I call virDomainMigrate () with the following parameters virDomainMigrate (localDomain, (virConnectPtr)dconn, VIR_MIGRATE_LIVE, "vm_mig_dubi", "tcp:9.148.4.95:4444", 0 ); The connection with the target VM was established ok Still I get the following error: libvir: QEMU error : invalid argument in only tcp URIs are supported for KVM migrations looking at the code of qemu_driver.c /qemudDomainMigratePrepare2() is see the following code (for version2 case): if (!STREQLEN (uri_in, "tcp:", 6)) { qemudReportError (dconn, NULL, NULL, VIR_ERR_INVALID_ARG, "%s", _("only tcp URIs are supported for KVM migrations")); goto cleanup; } why is the strncmp using length 6 and not 4 . I think this is the reason for the failure . If I put a NULL af ter the "tcp:" then I do not fail here (strncmp stop at the first NULL) but I fail one step later pasrsing the port because the NULL terminates the string Do we need a fix here ? thanks Zvi Dubitzky Virtualization and System Architecture Email:dubi@il.ibm.com IBM Haifa Research Laboratory Phone: +972-4-8296182 Haifa, 31905, ISRAEL