Description of problem:

Start with the following NUMA VM:

<domain type='kvm'>
  <name>2node0</name>
  <uuid>4a95fbdf-9fcf-4668-97da-5b7cdb0cc6c8</uuid>
  <memory unit='KiB'>4194304</memory>
  <currentMemory unit='KiB'>4194304</currentMemory>
  <memoryBacking>
    <nosharepages/>
    <locked/>
  </memoryBacking>
  <vcpu placement='static'>4</vcpu>
  <numatune>
    <memory mode='strict' nodeset='0'/>
  </numatune>
  <os>
    <type arch='x86_64' machine='pc-i440fx-rhel7.1.0'>hvm</type>
    <boot dev='hd'/>
  </os>
  <features>
    <acpi/>
    <apic/>
    <pae/>
  </features>
  <cpu mode='host-passthrough'>
    <numa>
      <cell id='0' cpus='0-1' memory='2097152' unit='KiB'/>
      <cell id='1' cpus='2-3' memory='2097152' unit='KiB'/>
    </numa>
  </cpu>
  <clock offset='utc'>
    <timer name='rtc' tickpolicy='catchup'/>
    <timer name='pit' tickpolicy='delay'/>
    <timer name='hpet' present='no'/>
  </clock>
  <on_poweroff>destroy</on_poweroff>
  <on_reboot>restart</on_reboot>
  <on_crash>restart</on_crash>
  <pm>
    <suspend-to-mem enabled='no'/>
    <suspend-to-disk enabled='no'/>
  </pm>
  <devices>
    <emulator>/usr/libexec/qemu-kvm</emulator>
    <controller type='pci' index='0' model='pci-root'/>
    <controller type='usb' index='0'>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x2'/>
    </controller>
    <memballoon model='none'/>
  </devices>
</domain>

This allocates both nodes with no shared pages, locked on host node0.  This VM works, however if we want to split the guest nodes between host nodes, we need memnode attributes, so we make the following change:

@@ -9,7 +9,8 @@
   </memoryBacking>
   <vcpu placement='static'>4</vcpu>
   <numatune>
-    <memory mode='strict' nodeset='0'/>
+    <memnode cellid='0' mode='strict' nodeset='0'/>
+    <memnode cellid='1' mode='strict' nodeset='1'/>
   </numatune>
   <os>
     <type arch='x86_64' machine='pc-i440fx-rhel7.1.0'>hvm</type>

(nodeset can be the same to reproduce on a single node host)

This results in the following full XML:

<domain type='kvm'>
  <name>2node0-1</name>
  <uuid>abc65d75-e745-4ed0-8cf9-1b849c1f031f</uuid>
  <memory unit='KiB'>4194304</memory>
  <currentMemory unit='KiB'>4194304</currentMemory>
  <memoryBacking>
    <nosharepages/>
    <locked/>
  </memoryBacking>
  <vcpu placement='static'>4</vcpu>
  <numatune>
    <memnode cellid='0' mode='strict' nodeset='0'/>
    <memnode cellid='1' mode='strict' nodeset='1'/>
  </numatune>
  <os>
    <type arch='x86_64' machine='pc-i440fx-rhel7.1.0'>hvm</type>
    <boot dev='hd'/>
  </os>
  <features>
    <acpi/>
    <apic/>
    <pae/>
  </features>
  <cpu mode='host-passthrough'>
    <numa>
      <cell id='0' cpus='0-1' memory='2097152' unit='KiB'/>
      <cell id='1' cpus='2-3' memory='2097152' unit='KiB'/>
    </numa>
  </cpu>
  <clock offset='utc'>
    <timer name='rtc' tickpolicy='catchup'/>
    <timer name='pit' tickpolicy='delay'/>
    <timer name='hpet' present='no'/>
  </clock>
  <on_poweroff>destroy</on_poweroff>
  <on_reboot>restart</on_reboot>
  <on_crash>restart</on_crash>
  <pm>
    <suspend-to-mem enabled='no'/>
    <suspend-to-disk enabled='no'/>
  </pm>
  <devices>
    <emulator>/usr/libexec/qemu-kvm</emulator>
    <controller type='pci' index='0' model='pci-root'/>
    <controller type='usb' index='0'>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x2'/>
    </controller>
    <memballoon model='none'/>
  </devices>
</domain>

(name and uuid also changed)

This VM definition will not start and gets the following error:

2015-06-30 14:39:57.013+0000: starting up libvirt version: 1.2.16, package: 1.el7 (Red Hat, Inc. <http://bugzilla.redhat.com/bugzilla>, 2015-06-04-04:03:16, x86-034.build.eng.bos.redhat.com), qemu version: 2.3.0 (qemu-kvm-rhev-2.3.0-6.el7)
LC_ALL=C PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin QEMU_AUDIO_DRV=none /usr/libexec/qemu-kvm -name 2node0-1 -S -machine pc-i440fx-rhel7.1.0,accel=kvm,usb=off,mem-merge=off -cpu host -m 4096 -realtime mlock=on -smp 4,sockets=4,cores=1,threads=1 -object memory-backend-ram,id=ram-node0,size=2147483648,host-nodes=0,policy=bind -numa node,nodeid=0,cpus=0-1,memdev=ram-node0 -object memory-backend-ram,id=ram-node1,size=2147483648,host-nodes=1,policy=bind -numa node,nodeid=1,cpus=2-3,memdev=ram-node1 -uuid abc65d75-e745-4ed0-8cf9-1b849c1f031f -nographic -no-user-config -nodefaults -chardev socket,id=charmonitor,path=/var/lib/libvirt/qemu/2node0-1.monitor,server,nowait -mon chardev=charmonitor,id=monitor,mode=control -rtc base=utc,driftfix=slew -global kvm-pit.lost_tick_policy=discard -no-hpet -no-shutdown -global PIIX4_PM.disable_s3=1 -global PIIX4_PM.disable_s4=1 -boot strict=on -device piix3-usb-uhci,id=usb,bus=pci.0,addr=0x1.0x2 -msg timestamp=on
Domain id=37 is tainted: host-cpu
qemu-kvm: util/qemu-option.c:387: qemu_opt_get_bool_helper: Assertion `opt->desc && opt->desc->type == QEMU_OPT_BOOL' failed.
2015-06-30 14:40:03.938+0000: shutting down

gdb gives the following backtrace:

#0  0x00007ffff09905d7 in raise () from /lib64/libc.so.6
#1  0x00007ffff0991cc8 in abort () from /lib64/libc.so.6
#2  0x00007ffff0989546 in __assert_fail_base () from /lib64/libc.so.6
#3  0x00007ffff09895f2 in __assert_fail () from /lib64/libc.so.6
#4  0x0000555555857e3f in qemu_opt_get_bool_helper (opts=0x5555561677e0, 
    name=name@entry=0x55555588502e "mem-merge", defval=defval@entry=true, 
    del=del@entry=false) at util/qemu-option.c:387
#5  0x000055555585818a in qemu_opt_get_bool (opts=<optimized out>, 
    name=name@entry=0x55555588502e "mem-merge", defval=defval@entry=true)
    at util/qemu-option.c:397
#6  0x00005555556f2b04 in host_memory_backend_init (obj=0x555556179a90)
    at backends/hostmem.c:234
#7  0x00005555557a2d39 in object_init_with_type (obj=0x555556179a90, 
    ti=0x55555613ac80) at qom/object.c:309
#8  0x00005555557a31ef in object_initialize_with_type (
    data=data@entry=0x555556179a90, size=<optimized out>, 
    type=type@entry=0x55555613ac80) at qom/object.c:343
#9  0x00005555557a3341 in object_new_with_type (type=0x55555613ac80)
    at qom/object.c:429
#10 0x00005555557a33b5 in object_new (
    typename=typename@entry=0x555556179730 "memory-backend-ram")
    at qom/object.c:439
#11 0x00005555556e1db5 in object_add (
    type=0x555556179730 "memory-backend-ram", id=0x5555561796c0 "ram-node0", 
    qdict=qdict@entry=0x5555561783b0, v=0x555556179850, 
    errp=errp@entry=0x7fffffffdbc8) at qmp.c:643
#12 0x00005555556cf144 in object_create (opts=<optimized out>, 
    opaque=<optimized out>) at vl.c:2632
#13 0x0000555555858edb in qemu_opts_foreach (list=<optimized out>, 
    func=func@entry=0x5555556cefa0 <object_create>, opaque=opaque@entry=0x0, 
    abort_on_failure=abort_on_failure@entry=0) at util/qemu-option.c:1059
#14 0x00005555555e0857 in main (argc=<optimized out>, argv=<optimized out>, 
    envp=<optimized out>) at vl.c:4040

This implicates the mem-merge option, which is controlled via <nosharepages/>

Removing the option from the XML allows the VM to start, but should not be necessary.

Version-Release number of selected component (if applicable):
qemu-kvm-rhev-2.3.0-6.el7.x86_64
libvirt-1.2.16-1.el7.x86_64

How reproducible:
100%

Steps to Reproduce:
1. Define the above VMs
2.
3.

Actual results:
Cannot use <nosharepages/> in combination with //numatune/memnode

Expected results:
//numatune/memnode should be compatible with <nosharepages/>

Additional info: