Hello, I start virtual machine this way:
$ qemu-img create -f qcow2 newcd-qemu.qcow2 10G $ qemu-system-i386 -enable-kvm -display vnc=localhost:0 -hda newcd-qemu.qcow2 -cdrom newcd-qemu.iso -m 256 -boot once=d While virtual machine operation I have these logs in dmesg: [Mon Oct 26 23:35:18 2015] kvm: zapping shadow pages for mmio generation wraparound [Mon Oct 26 23:35:18 2015] kvm: zapping shadow pages for mmio generation wraparound [Mon Oct 26 23:35:21 2015] kvm [15181]: vcpu0 disabled perfctr wrmsr: 0xc2 data 0xffff [Mon Oct 26 23:35:21 2015] kvm [15181]: vcpu0 unhandled rdmsr: 0x570 [Tue Oct 27 00:05:27 2015] kvm [15181]: vcpu0 disabled perfctr wrmsr: 0xc2 data 0xffff [Tue Oct 27 00:05:27 2015] kvm [15181]: vcpu0 unhandled rdmsr: 0x570 And after on the commands $ sudo modprobe nbd max_part=16 $ sudo qemu-nbd -c /dev/nbd0 newcd-qemu.qcow2 $ sudo mount /dev/nbd0p1 /mnt/ mount: special device /dev/nbd0p1 does not exist $ sudo umount /mnt/ umount: /mnt/: not mounted $ sudo qemu-nbd -d /dev/nbd0 I have these logs in dmesg: [Tue Oct 27 01:17:39 2015] nbd: registered device at major 43 [Tue Oct 27 01:17:40 2015] nbd0: p1 p2 < p5 > [Tue Oct 27 01:17:42 2015] block nbd0: NBD_DISCONNECT [Tue Oct 27 01:17:42 2015] block nbd0: Receive control failed (result -32) [Tue Oct 27 01:17:42 2015] block nbd0: queue cleared Qemu version: 1:2.4+dfsg-4 (debian testing weekly build from 19.10.2015) Note: on another computer the same commands run without errors. Ready to supplement any required tests and logs. Regards, Игорь
