device: 0.087 debug: 0.079 files: 0.077 network: 0.074 socket: 0.074 boot: 0.074 PID: 0.073 vnc: 0.072 other: 0.071 permissions: 0.071 performance: 0.067 graphic: 0.065 semantic: 0.064 KVM: 0.052 KVM: 0.748 debug: 0.059 boot: 0.034 socket: 0.026 PID: 0.026 performance: 0.025 other: 0.023 device: 0.020 semantic: 0.012 files: 0.009 permissions: 0.006 network: 0.005 graphic: 0.005 vnc: 0.002 Invalid parameter 'queues'. multi-queue vhost-user backends does not work. The command line which I use: /usr/bin/qemu-system-x86_64 -name instance-00000006 -S -machine pc-i440fx-2.4,accel=kvm,usb=off -cpu Haswell-noTSX,+abm,+pdpe1gb,+rdrand,+f16c,+osxsave,+pdcm,+xtpr,+tm2,+est,+smx,+vmx,+ds_cpl,+monitor,+dtes64,+pbe,+tm,+ht,+ss,+acpi,+ds,+vme -m 1024 -realtime mlock=off -smp 1,sockets=1,cores=1,threads=1 -object memory-backend-file,id=ram-node0,prealloc=yes,mem-path=/hugepages/libvirt/qemu,share=yes,size=1073741824 -numa node,nodeid=0,cpus=0,memdev=ram-node0 -uuid 54d61ffc-c8cf-4227-9610-96bcf1590984 -smbios type=1,manufacturer=OpenStack,product=OpenStack,version=2014.1.3,serial=44454c4c-3300-1043-804c-b5c04f463532,uuid=54d61ffc-c8cf-4227-9610-96bcf1590984 -no-user-config -nodefaults -mon chardev=charmonitor,id=monitor,mode=control -rtc base=utc,driftfix=slew -global kvm-pit.lost_tick_policy=discard -no-hpet -no-shutdown -boot strict=on -device piix3-usb-uhci,id=usb,bus=pci.0,addr=0x1.0x2 -drive file=/var/lib/nova/instances/54d61ffc-c8cf-4227-9610-96bcf1590984/disk,if=none,id=drive-virtio-disk0,format=qcow2,cache=none -device virtio-blk-pci,scsi=off,bus=pci.0,addr=0x4,drive=drive-virtio-disk0,id=virtio-disk0,bootindex=1 -chardev socket,id=charnet0,path=/var/run/vrouter/uvh_vif_tap35abd3c0-4f -netdev type=vhost-user,id=hostnet0,chardev=charnet0,queues=5 -device virtio-net-pci,netdev=hostnet0,id=net0,mq=on,mac=02:35:ab:d3:c0:4f,bus=pci.0,mq=on,addr=0x3 -chardev file,id=charserial0,path=/var/lib/nova/instances/54d61ffc-c8cf-4227-9610-96bcf1590984/console.log -device isa-serial,chardev=charserial0,id=serial0 -chardev pty,id=charserial1 -device isa-serial,chardev=charserial1,id=serial1 -device usb-tablet,id=input0 -vnc 10.10.6.14:0 -k en-us -device cirrus-vga,id=video0,bus=pci.0,addr=0x2 -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x5 -msg timestamp=on The error information : 2015-09-14T06:16:05.914264Z qemu-system-x86_64: -netdev type=vhost-user,id=hostnet0,chardev=charnet0,queues=5: Invalid parameter 'queues' You should use qemu 2.5.0. Looking through old bug tickets... can you still reproduce this issue with the latest version of QEMU? Or could we close this ticket nowadays? [Expired for QEMU because there has been no activity for 60 days.]