semantic: 0.269 other: 0.201 device: 0.071 files: 0.059 debug: 0.054 permissions: 0.047 vnc: 0.045 socket: 0.043 KVM: 0.041 boot: 0.037 network: 0.036 PID: 0.036 graphic: 0.031 performance: 0.029 performance: 0.244 KVM: 0.175 files: 0.131 debug: 0.119 other: 0.076 PID: 0.053 semantic: 0.037 device: 0.034 boot: 0.030 network: 0.029 socket: 0.021 permissions: 0.020 graphic: 0.017 vnc: 0.013 GCC -O2 causes segfaults unless compiled without optimizations, no system may be ran except the default with -kvm-enabled I had to modify config-host.mak and remove -O2 from CFLAGS to be able to work without kvm. GCC 4.4.4 qemu-0.14.1 ***NOTE: this has been an issue for several versions. Sorry, that there were no reactions to this ticket when you've opened it. Since both, GCC 4.4 and QEMU 0.14 are quite outdated nowadays, and AFAIK nobody complains about this issue with newer versions anymore, I think we can close this bug nowadays. If you still have this problem with the latest version of QEMU, please feel free to open this ticket again.