In comment #2 https://bugs.launchpad.net/ubuntu/+source/qemu-kvm/+bug/795717/comments/2 gdahlman's observation: {{ As an update I can boot when the guest is restricted to a single cpu ... }}
I think means that on the VM host if /usr/bin/kvm is forced to run on only one CPU via setting its processor affinity (via /usr/bin/taskset from the util-linux package) this issue does not occur. I can and will test that too soon. If it's true it explains a bit of why Ubuntu VM guests only sometime hang. The /usr/bin/kvm process running them might only sometimes switch CPUs while the VM guest is rebooting while /usr/bin/kvm running 32-bit RHEL 5 with 2 CPUs might always switch CPUs while the VM guest is rebooting. Also of note, 64-bit RHEL 5 does not use kvm-clock as a clocksource. For example: 64-bit RHEL 5 $ sudo cat /sys/devices/system/clocksource/clocksource0/available_clocksource jiffies 32-bit RHEL 5 $ sudo cat /sys/devices/system/clocksource/clocksource0/available_clocksource acpi_pm jiffies hpet tsc pit kvm-clock Both x86 and x86_64 RHEL 6 use kvm-clock but also linux kernel 2.6.32 I think by not using kvm-clock 64-bit RHEL 5 is not 100% vulnerable the way 32-bit RHEL 5 is. -- You received this bug notification because you are a member of Ubuntu Server Team, which is subscribed to qemu-kvm in Ubuntu. https://bugs.launchpad.net/bugs/795717 Title: 32bit rhel and centos 5.(5|6) hangs on boot on natty To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/795717/+subscriptions -- Ubuntu-server-bugs mailing list Ubuntu-server-bugs@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-server-bugs
