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Description of problem: Cannot hot plug-in macvtap device to guest Version-Release number of selected component (if applicable): qemu-kvm-0.12.1.2-2.184.el6.x86_64 How reproducible: always Steps to Reproduce: 1.boot a guest 2.hot plug a macvtap based nic by netdev_add tap,id=xwei,fd=5 5<>/dev/tap5 3. Actual results: qemu-kvm will raise error from monitor (qemu) netdev_add tap,id=xwei,vhost=on,fd=14 14<>/dev/tap14 netdev_add: extraneous characters at the end of line if drop the last part: (qemu) netdev_add tap,id=xwei,vhost=on,fd=14 TUNGETIFF ioctl() failed: Invalid argument TUNSETOFFLOAD ioctl() failed: Bad address Expected results: qemu-kvm should able to hot plug a macvtap based nic Additional info: if boot a guest by : with macvtap based nic: qemu-kvm ..... -netdev tap,id=xwei,vhost=on,fd=5 5<>/dev/tap5 \ -device virtio-net-pci,netdev=xwei,mac=xxxxx \ \ 6<>/dev/tap6 ... and then hot plug a macvtap based nic with above steps works fine.
(In reply to comment #0) > and then hot plug a macvtap based nic with above steps > works fine. Sorry for potential unclear,I mean: 1) if boot a guest with two ioctl attached but only use one by: qemu-kvm ... \ \ 5<>/dev/tap5 \ \ 6<>/dev/tap6 \ \ -netdev tap,id=cold-plug,vhost=on,fd=5 \ \ -device virtio-net-pci,netdev=code-plug,mac=xxxxx 2) then the guest boots,after guest up, do hot plug by: (qemu)netdev_add tap,id=hot-plug,vhost=on,fd=6 (qemu)device_add virtio-net-pci,netdev=hot-plug,mac=xxxx in this way of hot plug, qemu does not error and inside guest, hot plugged nic can got a ip from dhcp. 3) Just my opinion , this may caused by the qemu monitor doesn't accept and parse the " 14<>/dev/tap14 " as a option, here it treat " 14<>/dev/tap14 " as a bunch of mistype. same error when attached anything at the end of netdev_add cmd: (qemu) netdev_add tap,id=hot1,vhost=on,fd=17 17<>/dev/tap17 netdev_add: extraneous characters at the end of line (qemu) netdev_add tap,id=hot1,vhost=on,fd=17 alsfa netdev_add: extraneous characters at the end of line