[virsh] error: unknown OS type hvm解决办法

今天在linux服务器上编译安装升级了下qemu，升级命令如下：

root@ubuntu:/opt/qemu-2.0.0# ./configure  --prefix=/usr/local/ --target-list=x86_64-softmmu
root@ubuntu:/opt/qemu-2.0.0# make
root@ubuntu:/opt/qemu-2.0.0# make install

顺利编译安装后，去define了一个虚拟机，结果报了如下错误：

root@ubuntu:~# virsh define test.xml 
error: Failed to define domain from test.xml
error: unknown OS type hvm

好奇怪，便查看了下domain capabilities，命令：

root@ubuntu:~# virsh capabilities
<capabilities>

  <host>
    <uuid>44454c4c-4e00-1038-8050-b2c04f5a3258</uuid>
    <cpu>
      <arch>x86_64</arch>
      <model>Nehalem</model>
      <vendor>Intel</vendor>
      <topology sockets='1' cores='4' threads='1'/>
      <feature name='rdtscp'/>
      <feature name='dca'/>
      <feature name='xtpr'/>
      <feature name='tm2'/>
      <feature name='est'/>
      <feature name='vmx'/>
      <feature name='ds_cpl'/>
      <feature name='monitor'/>
      <feature name='pbe'/>
      <feature name='tm'/>
      <feature name='ht'/>
      <feature name='ss'/>
      <feature name='acpi'/>
      <feature name='ds'/>
      <feature name='vme'/>
    </cpu>
    <power_management/>
    <migration_features>
      <live/>
      <uri_transports>
        <uri_transport>tcp</uri_transport>
      </uri_transports>
    </migration_features>
    <topology>
      <cells num='2'>
        <cell id='0'>
          <cpus num='4'>
            <cpu id='0'/>
            <cpu id='2'/>
            <cpu id='4'/>
            <cpu id='6'/>
          </cpus>
        </cell>
        <cell id='1'>
          <cpus num='4'>
            <cpu id='1'/>
            <cpu id='3'/>
            <cpu id='5'/>
            <cpu id='7'/>
          </cpus>
        </cell>
      </cells>
    </topology>
  </host>

</capabilities>

跟正常情况下相比，发现少了<guest> 段落，下面贴下正常情况下的domain capabilities的情况：

<capabilities>

  <host>
    <uuid>01192eea-8053-cb11-a16c-f9dcbe14b1ee</uuid>
    <cpu>
      <arch>x86_64</arch>
      <model>Westmere</model>
      <vendor>Intel</vendor>
      <topology sockets='1' cores='2' threads='2'/>
      <feature name='invpcid'/>
      <feature name='erms'/>
      <feature name='bmi2'/>
      <feature name='smep'/>
      <feature name='avx2'/>
      <feature name='bmi1'/>
      <feature name='fsgsbase'/>
      <feature name='abm'/>
      <feature name='rdtscp'/>
      <feature name='pdpe1gb'/>
      <feature name='rdrand'/>
      <feature name='f16c'/>
      <feature name='avx'/>
      <feature name='osxsave'/>
      <feature name='xsave'/>
      <feature name='tsc-deadline'/>
      <feature name='movbe'/>
      <feature name='pcid'/>
      <feature name='pdcm'/>
      <feature name='xtpr'/>
      <feature name='fma'/>
      <feature name='tm2'/>
      <feature name='est'/>
      <feature name='vmx'/>
      <feature name='ds_cpl'/>
      <feature name='monitor'/>
      <feature name='dtes64'/>
      <feature name='pclmuldq'/>
      <feature name='pbe'/>
      <feature name='tm'/>
      <feature name='ht'/>
      <feature name='ss'/>
      <feature name='acpi'/>
      <feature name='ds'/>
      <feature name='vme'/>
    </cpu>
    <power_management>
      <suspend_mem/>
      <suspend_disk/>
      <suspend_hybrid/>
    </power_management>
    <migration_features>
      <live/>
      <uri_transports>
        <uri_transport>tcp</uri_transport>
      </uri_transports>
    </migration_features>
    <topology>
      <cells num='1'>
        <cell id='0'>
          <memory unit='KiB'>3732188</memory>
          <cpus num='4'>
            <cpu id='0' socket_id='0' core_id='0' siblings='0-1'/>
            <cpu id='1' socket_id='0' core_id='0' siblings='0-1'/>
            <cpu id='2' socket_id='0' core_id='1' siblings='2-3'/>
            <cpu id='3' socket_id='0' core_id='1' siblings='2-3'/>
          </cpus>
        </cell>
      </cells>
    </topology>
    <secmodel>
      <model>none</model>
      <doi>0</doi>
    </secmodel>
    <secmodel>
      <model>dac</model>
      <doi>0</doi>
      <baselabel type='kvm'>+0:+0</baselabel>
      <baselabel type='qemu'>+0:+0</baselabel>
    </secmodel>
  </host>

  <guest>
    <os_type>hvm</os_type>
    <arch name='i686'>
      <wordsize>32</wordsize>
      <emulator>/usr/bin/qemu-system-i386</emulator>
      <machine canonical='pc-i440fx-trusty' maxCpus='255'>pc</machine>
      <machine maxCpus='255'>pc-0.12</machine>
      <machine maxCpus='255'>pc-1.3</machine>
      <machine maxCpus='255'>pc-q35-1.6</machine>
      <machine canonical='pc-1.0-qemu-kvm' maxCpus='255'>pc-1.0-precise</machine>
      <machine maxCpus='255'>pc-q35-1.5</machine>
      <machine maxCpus='1'>xenpv</machine>
      <machine maxCpus='255'>pc-i440fx-1.6</machine>
      <machine maxCpus='255'>pc-i440fx-1.7</machine>
      <machine maxCpus='255'>pc-0.11</machine>
      <machine maxCpus='255'>pc-0.10</machine>
      <machine maxCpus='255'>pc-1.2</machine>
      <machine maxCpus='1'>isapc</machine>
      <machine maxCpus='255'>pc-q35-1.4</machine>
      <machine maxCpus='128'>xenfv</machine>
      <machine maxCpus='255'>pc-0.15</machine>
      <machine maxCpus='255'>pc-0.14</machine>
      <machine maxCpus='255'>pc-i440fx-1.5</machine>
      <machine canonical='pc-q35-2.0' maxCpus='255'>q35</machine>
      <machine maxCpus='255'>pc-i440fx-1.4</machine>
      <machine maxCpus='255'>pc-1.1</machine>
      <machine maxCpus='255'>pc-q35-1.7</machine>
      <machine canonical='pc-1.0' maxCpus='255'>pc-1.0-qemu-kvm</machine>
      <machine maxCpus='255'>pc-i440fx-2.0</machine>
      <machine maxCpus='255'>pc-0.13</machine>
      <domain type='qemu'>
      </domain>
      <domain type='kvm'>
        <emulator>/usr/bin/qemu-system-i386</emulator>
      </domain>
    </arch>
    <features>
      <cpuselection/>
      <deviceboot/>
      <acpi default='on' toggle='yes'/>
      <apic default='on' toggle='no'/>
      <pae/>
      <nonpae/>
    </features>
  </guest>

  <guest>
    <os_type>hvm</os_type>
    <arch name='x86_64'>
      <wordsize>64</wordsize>
      <emulator>/usr/bin/qemu-system-x86_64</emulator>
      <machine canonical='pc-i440fx-trusty' maxCpus='255'>pc</machine>
      <machine maxCpus='255'>pc-1.3</machine>
      <machine maxCpus='255'>pc-0.12</machine>
      <machine maxCpus='255'>pc-q35-1.6</machine>
      <machine canonical='pc-1.0-qemu-kvm' maxCpus='255'>pc-1.0-precise</machine>
      <machine maxCpus='255'>pc-q35-1.5</machine>
      <machine maxCpus='1'>xenpv</machine>
      <machine maxCpus='255'>pc-i440fx-1.6</machine>
      <machine maxCpus='255'>pc-i440fx-1.7</machine>
      <machine maxCpus='255'>pc-0.11</machine>
      <machine maxCpus='255'>pc-1.2</machine>
      <machine maxCpus='255'>pc-0.10</machine>
      <machine maxCpus='1'>isapc</machine>
      <machine maxCpus='255'>pc-q35-1.4</machine>
      <machine maxCpus='128'>xenfv</machine>
      <machine maxCpus='255'>pc-0.15</machine>
      <machine maxCpus='255'>pc-0.14</machine>
      <machine maxCpus='255'>pc-i440fx-1.5</machine>
      <machine maxCpus='255'>pc-i440fx-1.4</machine>
      <machine canonical='pc-q35-2.0' maxCpus='255'>q35</machine>
      <machine maxCpus='255'>pc-1.1</machine>
      <machine maxCpus='255'>pc-q35-1.7</machine>
      <machine canonical='pc-1.0' maxCpus='255'>pc-1.0-qemu-kvm</machine>
      <machine maxCpus='255'>pc-i440fx-2.0</machine>
      <machine maxCpus='255'>pc-0.13</machine>
      <domain type='qemu'>
      </domain>
      <domain type='kvm'>
        <emulator>/usr/bin/qemu-system-x86_64</emulator>
      </domain>
    </arch>
    <features>
      <cpuselection/>
      <deviceboot/>
      <acpi default='on' toggle='yes'/>
      <apic default='on' toggle='no'/>
    </features>
  </guest>

</capabilities>

这时问题就很明显了，肯定是升级qemu时哪里出现了问题，经过多次尝试，终于发现了原因：我们需要将 qemu-system-x86_64 安装在 /usr/bin/ 目录下才能正常define虚拟机。

然后再次重新编译升级qemu，指定 prefix=/usr/即可，命令如下：

root@ubuntu:/opt/qemu-2.0.0# ./configure  --prefix=/usr/ --target-list=x86_64-softmmu
root@ubuntu:/opt/qemu-2.0.0# make
root@ubuntu:/opt/qemu-2.0.0# make install

然后删除原来/usr/local/bin/目录下残留的qemu-*文件即可。