other: 0.817 debug: 0.806 semantic: 0.804 permissions: 0.785 graphic: 0.765 device: 0.765 performance: 0.724 files: 0.703 PID: 0.695 socket: 0.622 network: 0.607 KVM: 0.592 vnc: 0.590 boot: 0.571 Undefined References I've been able to make qemu on ubuntu 13.04 for all last releases: 1.4.0 -> 1.5.0 Unfortunately, when I launch one of them with a Cisco ASA, it crashes inside GNS3 (latest release) for Ubuntu. The top GNS3 developer told me they experienced similar results and advised me to use qemu 1.1.0. The problem is that I cannot link that version. I always have these errors: "LINK qemu-ga qemu-timer.o: In function `dynticks_rearm_timer': /home/actionmystique/Downloads/qemu-1.1.0/qemu-timer.c:538: undefined reference to `timer_gettime' /home/actionmystique/Downloads/qemu-1.1.0/qemu-timer.c:551: undefined reference to `timer_settime' qemu-timer.o: In function `dynticks_stop_timer': /home/actionmystique/Downloads/qemu-1.1.0/qemu-timer.c:524: undefined reference to `timer_delete' qemu-timer.o: In function `dynticks_start_timer': /home/actionmystique/Downloads/qemu-1.1.0/qemu-timer.c:510: undefined reference to `timer_create' collect2: error: ld returned 1 exit status make: *** [qemu-ga] Error 1" The man pages say we need to link with '-lrt' option, but I could not find it in the Makefile. I do not know how to correct this issue. As you note, 1.1 is now pretty old; you will be much better off in the long run investigating why your guest OS doesn't work under current QEMU. This is a change in glibc. Since version 2.17, clock_gettime() and friends were moved from -lrt to the main libc, so for linking with clock_gettime(), -lrt isn't needed anymore. However, (old) qemu configure only checked clock_gettime(), and used other functions like timer_create() &Co above. There was a patch: commit 8bacde8d86a09699207d85d4bab06162aed18dc4 Author: Natanael Copa