Red Hat Bugzilla – Bug 1258339
qemu-kvm boot up failed with "can't use already busy memdev"
Last modified: 2016-05-16 00:08:27 EDT
Description of problem: qemu-kvm boot up failed with "can't use already busy memdev" Version-Release number of selected component (if applicable): # rpm -q qemu-kvm-rhev qemu-kvm-rhev-2.3.0-21.el7.x86_64 How reproducible: 100% Steps to Reproduce: 1. boot up vm with one numa node /bin/qemu-kvm \ -S \ -name 'virt-tests-vm1' \ -sandbox off \ -machine pc \ -nodefaults \ -vga cirrus \ -chardev socket,id=qmp_id_qmpmonitor1,path=/tmp/monitor-qmpmonitor1-20150831-132748-EY9Ue1UE,server,nowait \ -mon chardev=qmp_id_qmpmonitor1,mode=control \ -chardev socket,id=qmp_id_catch_monitor,path=/tmp/monitor-catch_monitor-20150831-132748-EY9Ue1UE,server,nowait \ -mon chardev=qmp_id_catch_monitor,mode=control \ -device pvpanic,ioport=0x505,id=idm5gMcB \ -chardev socket,id=serial_id_serial0,path=/tmp/serial-serial0-20150831-132748-EY9Ue1UE,server,nowait \ -device isa-serial,chardev=serial_id_serial0 \ -chardev socket,id=seabioslog_id_20150831-132748-EY9Ue1UE,path=/tmp/seabios-20150831-132748-EY9Ue1UE,server,nowait \ -device isa-debugcon,chardev=seabioslog_id_20150831-132748-EY9Ue1UE,iobase=0x402 \ -device ich9-usb-uhci1,id=usb1,bus=pci.0,addr=03 \ -drive id=drive_image1,if=none,cache=none,snapshot=off,aio=native,format=qcow2,file=/mnt/nfs_images/RHEL-Server-7.2-64-virtio.qcow2 \ -device virtio-blk-pci,id=image1,drive=drive_image1,bootindex=0,bus=pci.0,addr=04 \ -device virtio-net-pci,mac=9a:c1:c2:c3:c4:c5,id=idkgc4ST,vectors=4,netdev=idFlR5jA,bus=pci.0,addr=05 \ -netdev tap,id=idFlR5jA \ -m 4096,slots=4,maxmem=32G \ -object memory-backend-ram,size=4096M,host-nodes=0,policy=bind,id=mem-mem0 \ -device pc-dimm,id=dimm-mem0,memdev=mem-mem0 \ -smp 4,maxcpus=4,cores=2,threads=1,sockets=2 \ -numa node,memdev=mem-mem0 \ -cpu 'SandyBridge',+kvm_pv_unhalt \ -device usb-tablet,id=usb-tablet1,bus=usb1.0,port=1 \ -vnc :0 \ -rtc base=utc,clock=host,driftfix=slew \ -boot order=cdn,once=c,menu=off,strict=off \ -enable-kvm \ -monitor stdio 2. 3. Actual results: (qemu) qemu-kvm: -device pc-dimm,id=dimm-mem0,memdev=mem-mem0: can't use already busy memdev: mem-mem0 Expected results: boot up successfully Additional info: boot up successfully with "-numa node", no memdev option.
You are trying to use the same mem-dev for two different memory regions: * The first 4GB, that's non-hotplug memory living in the first (only) NUMA node (-numa node,memdev=mem-mem0) * Extra hotplugged memory beyond the first non-hotplug 4GB (-object pc-dimm) You can't do that. If you want the guest to have just 4GB non-hotplug memory, simply don't use -object pc-dimm. If you want the guest to have 8GB (4GB non-hotplug and 4GB hotplug), you need two memory backend objects, 4GB each.