ok getting the serial console to work was not that hard. here is the relevant serial output of the failing guest (full output is attached as file):
[ 0.010706] mce: CPU supports 10 MCE banks [ 0.011279] ACPI: Core revision 20110623 [ 0.014769] ..TIMER: vector=0x30 apic1=0 pin1=2 apic2=-1 pin2=-1 [ 0.025876] CPU0: Intel(R) Core(TM)2 Quad CPU Q9300 @ 2.50GHz stepping 07 [ 0.027998] Performance Events: [ 0.027998] general protection fault: 0000 [#1] SMP [ 0.027998] CPU 0 [ 0.027998] Modules linked in: [ 0.027998] [ 0.027998] Pid: 1, comm: swapper/0 Not tainted 3.2.12-gentoo #1 Bochs Bochs [ 0.027998] RIP: 0010:[<ffffffff81aa553f>] [<ffffffff81aa553f>] intel_pmu_init+0x283/0x85e [ 0.027998] RSP: 0018:ffff88000f8b9ea0 EFLAGS: 00000202 [ 0.027998] RAX: 0000000000000003 RBX: 0000000000000000 RCX: 0000000000000345 [ 0.027998] RDX: 0000000000000003 RSI: 0000000007280202 RDI: ffffffff81a7efa8 [ 0.027998] RBP: ffff88000f8b9eb0 R08: 0000000000000000 R09: ffffffff81a7ee70 [ 0.027998] R10: 0000000000000001 R11: 0000000000000000 R12: ffffffff81aa4955 [ 0.027998] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 [ 0.027998] FS: 0000000000000000(0000) GS:ffff88000fc00000(0000) knlGS:0000000000000000 [ 0.027998] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b [ 0.027998] CR2: 0000000000000000 CR3: 0000000001a05000 CR4: 00000000000006f0 [ 0.027998] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 0.027998] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 [ 0.027998] Process swapper/0 (pid: 1, threadinfo ffff88000f8b8000, task ffff88000f8b0000) [ 0.027998] Stack: [ 0.027998] 0000000000000000 ffffffff81b1b550 ffff88000f8b9ef0 ffffffff81aa4989 [ 0.027998] 0000000000000040 ffffffff81a800d8 ffff88000f8b9f20 ffffffff81b1b550 [ 0.027998] ffffffff81aa4955 0000000000000000 ffff88000f8b9f20 ffffffff810002ea [ 0.027998] Call Trace: [ 0.027998] [<ffffffff81aa4989>] init_hw_perf_events+0x34/0x3ef [ 0.027998] [<ffffffff81aa4955>] ? check_bugs+0x2d/0x2d [ 0.027998] [<ffffffff810002ea>] do_one_initcall+0x7a/0x12c [ 0.027998] [<ffffffff81a9eb45>] kernel_init+0x7a/0x141 [ 0.027998] [<ffffffff814963b4>] kernel_thread_helper+0x4/0x10 [ 0.027998] [<ffffffff81a9eacb>] ? start_kernel+0x339/0x339 [ 0.027998] [<ffffffff814963b0>] ? gs_change+0xb/0xb [ 0.027998] Code: 48 d3 e0 48 ff c8 41 ff ca 48 89 05 b4 99 fd ff 7e 2b 83 e2 1f b8 03 00 00 00 83 fa 02 b9 45 03 00 00 0f 4f c2 89 05 91 99 fd ff <0f> 32 48 c1 e2 20 89 c0 48 09 c2 48 89 15 ef 99 fd ff e8 cf be [ 0.027998] RIP [<ffffffff81aa553f>] intel_pmu_init+0x283/0x85e [ 0.027998] RSP <ffff88000f8b9ea0> [ 0.029015] ---[ end trace 4eaa2a86a8e2da22 ]--- [ 0.030006] swapper/0 used greatest stack depth: 5576 bytes left [ 0.031005] Kernel panic - not syncing: Attempted to kill init! [ 0.032006] Pid: 1, comm: swapper/0 Tainted: G D 3.2.12-gentoo #1 [ 0.033000] Call Trace: [ 0.034003] [<ffffffff8148d64e>] panic+0x8c/0x198 [ 0.035005] [<ffffffff8103e1f0>] do_exit+0x98/0x7d8 [ 0.036005] [<ffffffff8103c564>] ? kmsg_dump+0x46/0xd2 [ 0.037007] [<ffffffff81490078>] oops_end+0xb1/0xb9 [ 0.038001] [<ffffffff81004bd9>] die+0x55/0x60 [ 0.039005] [<ffffffff8148fd30>] do_general_protection+0x12e/0x136 [ 0.040001] [<ffffffff81aa4955>] ? check_bugs+0x2d/0x2d [ 0.041005] [<ffffffff8148f83f>] general_protection+0x1f/0x30 [ 0.042001] [<ffffffff81aa4955>] ? check_bugs+0x2d/0x2d [ 0.043004] [<ffffffff81aa553f>] ? intel_pmu_init+0x283/0x85e [ 0.044001] [<ffffffff81aa4989>] init_hw_perf_events+0x34/0x3ef [ 0.045005] [<ffffffff81aa4955>] ? check_bugs+0x2d/0x2d [ 0.046003] [<ffffffff810002ea>] do_one_initcall+0x7a/0x12c [ 0.047003] [<ffffffff81a9eb45>] kernel_init+0x7a/0x141 [ 0.048000] [<ffffffff814963b4>] kernel_thread_helper+0x4/0x10 [ 0.049000] [<ffffffff81a9eacb>] ? start_kernel+0x339/0x339 [ 0.050008] [<ffffffff814963b0>] ? gs_change+0xb/0xb -- You received this bug notification because you are a member of qemu- devel-ml, which is subscribed to QEMU. https://bugs.launchpad.net/bugs/1037675 Title: Guest Kernel Panic if using "-cpu host" in qemu-kvm 1.1.1 Status in QEMU: New Bug description: After Upgrading to qemu-kvm-1.1.1-r1 from version 1.0.1-r1 my virtual machines (running gentoo linux) panic at intel_pmu_init. (detailed information including stacktrace are in the uploaded screenshot). When i remove the "-cpu host" option, the system starts normally. the command line from whicht the system is bootet: qemu-kvm -vnc :7 -usbdevice tablet -daemonize -m 256 -drive file=/data/virtual_machines/wgs-l08.img,if=virtio -boot c -k de -net nic,model=virtio,macaddr=12:12:00:12:34:63,vlan=0 -net tap,ifname=qtap6,script=no,downscript=no,vlan=0 -smp 2 -enable-kvm -cpu host -monitor unix:/var/run/qemu- kvm/wgs-l08.monitor,server,nowait also reported on gentoo bug tracker (with some more details of the host): https://bugs.gentoo.org/show_bug.cgi?id=431640 To manage notifications about this bug go to: https://bugs.launchpad.net/qemu/+bug/1037675/+subscriptions