1.Description of problem: It report use migration with shmem device is not supported , when I use the command "virsh migrate --live" to migrate a VM to another host. 2.Version-Release number of selected component (if applicable): libvirt 3.9.0 qemu-kvm 2.8.1 3.Steps to Reproduce: 1) Add serveral lines below to guest configuration <shmem name='my_shmem1'> <model type='ivshmem-plain'/> <size unit='M'>4</size> </shmem> 2) virsh start guest-1 3) virsh migrate --live guest-1 qemu+ssh://target/system Actual results: error: Requested operation is not valid: migration with shmem device is not supported 4.Code Review When using the command “virsh create guset-1.xml,it produce corresponding command below. “qemu-kvm -device ivshmem-plain, id=shmem0,memdev=shmmem-shmem0,bus=pci.0,addr=0xa” I read qemu-doc.texi in qemu-2.8.1 source code, which have a explain of migrating ivshmem below “With device property @option{master=on}, the guest will copy the shared memory on migration to the destination host. With @option{master=off}, the guest will not be able to migrate with the device attached.” But libvirt library can not recognize the property “master=on”. When I directly used command "qemu-kvm -device ivshmem-plain,id=shmem0,memdev=shmmem-shmem0,master=on,bus=pci.0,addr=0xa” to launch a guest, it can migrate in live. I review the code about qemu code with branch 2.8.1 and master from https://github.com/libvirt/libvirt, it have no configuration definition for “master=on” The below is the part of source code domain_conf.h struct _virDomainShmemDef { char *name; unsigned long long size; int model; /* enum virDomainShmemModel */ struct { bool enabled; virDomainChrSourceDef chr; } server; struct { bool enabled; unsigned vectors; virTristateSwitch ioeventfd; } msi; virDomainDeviceInfo info; };