[Qemu-discuss] (newbie) qemu unexpectedly closed the monitor: ftruncate: Invalid argument

[Archna Johnson]

Hello,

While trying to power on a VM using KVM-qemu, I see this failure. Could
someone please advise about what I am doing wrong?

libvir: QEMU Driver error : internal error: qemu unexpectedly closed the
monitor: ftruncate: Invalid argument
2018-10-26T19:18:06.394822Z qemu-kvm: -object
memory-backend-file,id=memnvdimm0,prealloc=yes,mem-path=/dev/dax0.0,share=yes,size=4294967296:
unable to map backing store for guest RAM: Invalid argument

Below is some information about the software and logs that I could pull:

Thanks!
Archna

virsh version

Compiled against library: libvirt 3.9.0

Using library: libvirt 3.9.0

Using API: QEMU 3.9.0

Running hypervisor: QEMU 2.10.0



Red Hat Enterprise Linux Server release 7.5 (Maipo)



Linux 4.19.0-1.el7.elrepo.x86_64 #1 SMP Mon Oct 22 10:40:32 EDT 2018 x86_64
x86_64 x86_64 GNU/Linux



ndctl version

63+


cat /var/log/libvirt/qemu/dax_vm.log

2018-10-26 19:18:06.341+0000: starting up libvirt version: 3.9.0, package:
14.el7_5.8 (Red Hat, Inc. <http://bugzilla.redhat.com/bugzilla>,
2018-09-04-07:27:24, x86-019.build.eng.bos.redhat.com), qemu version:
2.10.0(qemu-kvm-rhev-2.10.0-21.el7_5.6), hostname: <host-name>

LC_ALL=C PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin
QEMU_AUDIO_DRV=none /usr/libexec/qemu-kvm -name
guest=dax_vm,debug-threads=on -S -object
secret,id=masterKey0,format=raw,file=/var/lib/libvirt/qemu/domain-4-dax_vm/master-key.aes
-machine
pc-i440fx-rhel7.5.0,accel=kvm,usb=off,dump-guest-core=off,nvdimm=on -cpu
host -m size=67108864k,slots=2,maxmem=75497472k -realtime mlock=off -smp
8,sockets=8,cores=1,threads=1 -numa node,nodeid=0,cpus=0-7,mem=65536
-object
memory-backend-file,id=memnvdimm0,prealloc=yes,mem-path=/dev/dax0.0,share=yes,size=4294967296
-device nvdimm,node=0,memdev=memnvdimm0,id=nvdimm0,slot=0 -uuid
56012bbe-d950-11e8-8102-005056b801b1 -display none -no-user-config
-nodefaults -chardev
socket,id=charmonitor,path=/var/lib/libvirt/qemu/domain-4-dax_vm/monitor.sock,server,nowait
-mon chardev=charmonitor,id=monitor,mode=control -rtc base=utc -no-shutdown
-boot strict=on -device piix3-usb-uhci,id=usb,bus=pci.0,addr=0x1.0x2
-device virtio-scsi-pci,id=scsi0,bus=pci.0,addr=0x2 -device
virtio-serial-pci,id=virtio-serial0,bus=pci.0,addr=0x3 -drive
file=/dev/fox22_ds/dax_vm_DataONTAPv.raw,format=raw,if=none,id=drive-scsi0-0-0-0,cache=directsync
-device
scsi-hd,bus=scsi0.0,channel=0,scsi-id=0,lun=0,drive=drive-scsi0-0-0-0,id=scsi0-0-0-0,bootindex=1
-drive
file=/dev/fox22_ds/dax_vm_coredisk,format=raw,if=none,id=drive-scsi0-0-0-1,cache=directsync
-device
scsi-hd,bus=scsi0.0,channel=0,scsi-id=0,lun=1,drive=drive-scsi0-0-0-1,id=scsi0-0-0-1
-drive
file=/dev/fox22_ds/dax_vm_root_1,format=raw,if=none,id=drive-scsi0-0-0-2,cache=directsync
-device
scsi-hd,bus=scsi0.0,channel=0,scsi-id=0,lun=2,drive=drive-scsi0-0-0-2,id=scsi0-0-0-2
-drive
file=/dev/fox22_ds/dax_vm_data_1,format=raw,if=none,id=drive-scsi0-0-0-3,cache=directsync
-device
scsi-hd,bus=scsi0.0,channel=0,scsi-id=0,lun=3,drive=drive-scsi0-0-0-3,id=scsi0-0-0-3
-drive
file=/dev/fox22_ds/dax_vm_config.iso,format=raw,if=none,id=drive-ide0-1-0,readonly=on
-device ide-cd,bus=ide.1,unit=0,drive=drive-ide0-1-0,id=ide0-1-0 -netdev
tap,fd=26,id=hostnet0,vhost=on,vhostfd=31 -device
virtio-net-pci,netdev=hostnet0,id=net0,mac=52:54:00:ce:70:2c,bus=pci.0,addr=0x5
-netdev tap,fd=32,id=hostnet1,vhost=on,vhostfd=33 -device
virtio-net-pci,netdev=hostnet1,id=net1,mac=52:54:00:9c:a7:ac,bus=pci.0,addr=0x6
-chardev socket,id=charserial0,host=0.0.0.0,port=7200,telnet,server,nowait
-device isa-serial,chardev=charserial0,id=serial0 -chardev
socket,id=charserial1,host=0.0.0.0,port=7213,telnet,server,nowait -device
isa-serial,chardev=charserial1,id=serial1 -device
virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x4 -msg timestamp=on

2018-10-26 19:18:06.341+0000: Domain id=4 is tainted: high-privileges

2018-10-26 19:18:06.341+0000: Domain id=4 is tainted: host-cpu

ftruncate: Invalid argument

2018-10-26T19:18:06.394822Z qemu-kvm: -object
memory-backend-file,id=memnvdimm0,prealloc=yes,mem-path=/dev/dax0.0,share=yes,size=4294967296:
unable to map backing store for guest RAM: Invalid argument

2018-10-26 19:18:06.455+0000: shutting down, reason=failed

snippets from the xml file for the VM:

 <maxMemory slots='2' unit='KiB'>75497472</maxMemory>
  <memory unit='KiB'>71303168</memory>
  <currentMemory unit='KiB'>71303168</currentMemory>
  <vcpu placement='static'>8</vcpu>
  <os>
    <type arch='x86_64' machine='pc-i440fx-rhel7.5.0'>hvm</type>
    <boot dev='hd'/>
  </os>
  <features>
    <acpi/>
    <apic/>
    <pae/>
  </features>
  <cpu mode='host-passthrough' check='none'>
    <numa>
      <cell id='0' cpus='0-7' memory='67108864' unit='KiB'/>
    </numa>
  </cpu>

  <memballoon model='virtio'>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x04'
function='0x0'/>
    </memballoon>
    <memory model='nvdimm' access='shared'>
      <source>
        <path>/dev/dax0.0</path>
      </source>
      <target>
        <size unit='KiB'>4194304</size>
        <node>0</node>
      </target>
      <address type='dimm' slot='0'/>
    </memory>