1. 02 9月, 2011 4 次提交
  2. 26 8月, 2011 1 次提交
    • E
      snapshot: track current snapshot across restarts · 6766ff10
      Eric Blake 提交于
      Audit all changes to the qemu vm->current_snapshot, and make them
      update the saved xml file for both the previous and the new
      snapshot, so that there is always at most one snapshot with
      <active>1</active> in the xml, and that snapshot is used as the
      current snapshot even across libvirtd restarts.
      
      This patch does not fix the case of virDomainSnapshotDelete(,CHILDREN)
      where one of the children is the current snapshot; that will be later.
      
      * src/conf/domain_conf.h (_virDomainSnapshotDef): Alter member
      type and name.
      * src/conf/domain_conf.c (virDomainSnapshotDefParseString)
      (virDomainSnapshotDefFormat): Update clients.
      * docs/schemas/domainsnapshot.rng: Tighten rng.
      * src/qemu/qemu_driver.c (qemuDomainSnapshotLoad): Reload current
      snapshot.
      (qemuDomainSnapshotCreateXML, qemuDomainRevertToSnapshot)
      (qemuDomainSnapshotDiscard): Track current snapshot.
      6766ff10
  3. 15 8月, 2011 1 次提交
    • L
      qemu: support event_idx parameter for virtio disk and net devices · 73c0a148
      Laine Stump 提交于
      In some versions of qemu, both virtio-blk-pci and virtio-net-pci
      devices can have an event_idx setting that determines some details of
      event processing. When it is enabled, it "reduces the number of
      interrupts and exits for the guest". qemu will automatically enable
      this feature when it is available, but there may be cases where this
      new feature could actually make performance worse (NB: no such case
      has been found so far).
      
      As a safety switch in case such a situation is encountered in the
      field, this patch adds a new attribute "event_idx" to the <driver>
      element of both disk and interface devices. event_idx can be set to
      "on" (to force event_idx on in case qemu has it disabled by default)
      or "off" (for force event_idx off). In the case that event_idx support
      isn't present in qemu, the attribute is ignored (this on the advice of
      the qemu developer).
      
      docs/formatdomain.html.in: document the new flag (marking it as
         "don't mess with this!"
      docs/schemas/domain.rng: add event_idx in appropriate places
      src/conf/domain_conf.[ch]: add event_idx to parser and formatter
      src/libvirt_private.syms: export
         virDomainVirtioEventIdx(From|To)String
      src/qemu/qemu_capabilities.[ch]: detect and report event_idx in
         disk/net
      src/qemu/qemu_command.c: add event_idx parameter to qemu commandline
          when appropriate.
      tests/qemuxml2argvdata/qemuxml2argv-event_idx.args,
      tests/qemuxml2argvdata/qemuxml2argv-event_idx.xml,
      tests/qemuxml2argvtest.c,
      tests/qemuxml2xmltest.c: test cases for event_idx.
      73c0a148
  4. 13 8月, 2011 1 次提交
  5. 30 7月, 2011 2 次提交
    • E
      save: generate idempotent inactive xml for running domain · a8be259d
      Eric Blake 提交于
      Originally noticed by comparing the xml generated by virDomainSave
      with the xml produced by reparsing and redumping that xml, but I
      also did an audit of every last use of VIR_DOMAIN_XML_INACTIVE in
      domain_conf.c to ensure that no other discrepancies exist.
      
      * src/conf/domain_conf.c (virDomainDeviceInfoIsSet): Add
      parameter, and update all callers.  Make static.
      (virDomainNetDefFormat): Skip generated ifname.
      (virDomainDefFormatInternal): Skip default <seclabel>.
      (virDomainChrSourceDefParseXML): Skip generated pty path, and add
      parameter.  Update callers.
      * src/conf/domain_conf.h (virDomainDeviceInfoIsSet): Delete.
      * src/libvirt_private.syms (domain_conf.h): Update.
      a8be259d
    • E
      conf: make 'vnet' prefix a macro · dd20328f
      Eric Blake 提交于
      Using a macro ensures that all the code is looking for the same
      prefix.
      
      * src/conf/domain_conf.h (VIR_NET_GENERATED_PREFIX): New macro.
      * src/conf/domain_conf.c (virDomainNetDefParseXML): Use it.
      * src/uml/uml_conf.c (umlConnectTapDevice): Likewise.
      * src/qemu/qemu_command.c (qemuNetworkIfaceConnect): Likewise.
      Suggested by Laine Stump.
      dd20328f
  6. 29 7月, 2011 1 次提交
    • L
      conf: add <listen> subelement to domain <graphics> element · ef79fb5b
      Laine Stump 提交于
      Once it's plugged in, the <listen> element will be an optional
      replacement for the "listen" attribute that graphics elements already
      have. If the <listen> element is type='address', it will have an
      attribute called 'address' which will contain an IP address or dns
      name that the guest's display server should listen on. If, however,
      type='network', the <listen> element should have an attribute called
      'network' that will be set to the name of a network configuration to
      get the IP address from.
      
      * docs/schemas/domain.rng: updated to allow the <listen> element
      
      * docs/formatdomain.html.in: document the <listen> element and its
        attributes.
      
      * src/conf/domain_conf.[hc]:
      
        1) The domain parser, formatter, and data structure are modified to
           support 0 or more <listen> subelements to each <graphics>
           element. The old style "legacy" listen attribute is also still
           accepted, and will be stored internally just as if it were a
           separate <listen> element. On output (i.e. format), the address
           attribute of the first <listen> element of type 'address' will be
           duplicated in the legacy "listen" attribute of the <graphic>
           element.
      
        2) The "listenAddr" attribute has been removed from the unions in
           virDomainGRaphicsDef for graphics types vnc, rdp, and spice.
           This attribute is now in the <listen> subelement (aka
           virDomainGraphicsListenDef)
      
        3) Helper functions were written to provide simple access
           (both Get and Set) to the listen elements and their attributes.
      
      * src/libvirt_private.syms: export the listen helper functions
      
      * src/qemu/qemu_command.c, src/qemu/qemu_hotplug.c,
        src/qemu/qemu_migration.c, src/vbox/vbox_tmpl.c,
        src/vmx/vmx.c, src/xenxs/xen_sxpr.c, src/xenxs/xen_xm.c
      
        Modify all these files to use the listen helper functions rather
        than directly referencing the (now missing) listenAddr
        attribute. There can be multiple <listen> elements to a single
        <graphics>, but the drivers all currently only support one, so all
        replacements of direct access with a helper function indicate index
        "0".
      
      * tests/* - only 3 of these are new files added explicitly to test the
        new <listen> element. All the others have been modified to reflect
        the fact that any legacy "listen" attributes passed in to the domain
        parse will be saved in a <listen> element (i.e. one of the
        virDomainGraphicsListenDefs), and during the domain format function,
        both the <listen> element as well as the legacy attributes will be
        output.
      ef79fb5b
  7. 27 7月, 2011 1 次提交
    • M
      bandwidth: Integrate bandwidth into portgroups · fe957f0a
      Michal Privoznik 提交于
      Every DomainNetDef has a bandwidth, as does every portgroup.
      Whenever a DomainNetDef of type NETWORK is about to be used, a call is
      made to networkAllocateActualDevice(). This function chooses the "best"
      bandwidth object and places it in the DomainActualNetDef.
      From that point on, whenever some code needs to use the bandwidth data
      for the interface, it's retrieved with virDomainNetGetActualBandwidth(),
      which will always return the "best" info as determined in the
      previous step.
      fe957f0a
  8. 25 7月, 2011 1 次提交
    • M
      bandwidth: Add parsing and free functions · e2ed67a8
      Michal Privoznik 提交于
      These functions parse given XML node and return pointer to the
      output. Unknown elements are silently ignored. Attributes must
      be integer and must fit in unsigned long long.
      
      Free function frees elements of virBandwidth structure.
      e2ed67a8
  9. 22 7月, 2011 2 次提交
    • L
      conf: support abstracted interface info in domain interface XML · 07f41369
      Laine Stump 提交于
      the domain XML <interface> element is updated in the following ways:
      
      1) <virtualportprofile> can be specified when source type='network'
      (previously it was only valid for source type='direct')
      
      2) A new attribute "portgroup" has been added to the <source>
      element. When source type='network' (the only time portgroup is
      recognized), extra configuration information will be taken from the
      <portgroup> element of the given name in the network definition.
      
      3) Each virDomainNetDef now also potentially has a
      virDomainActualNetDef which is a private object (never
      exported/imported via the public API, and not defined in the RNG) that
      is used to maintain information about the physical device that was
      actually used for a NetDef of type VIR_DOMAIN_NET_TYPE_NETWORK.
      
      The virDomainActualNetDef will only be parsed/formatted if the
      parse/format function is called with the
      VIR_DOMAIN_XML_INTERNAL_ACTUAL_NET flag set (which is only needed when
      saving/loading a running domain's state info to the stateDir).
      07f41369
    • L
      conf: virDomainNetDef points to (rather than contains) virtPortProfile · 524655ee
      Laine Stump 提交于
      The virtPortProfile in the domain interface struct is now a separately
      allocated object *pointed to by* (rather than contained in) the main
      virDomainNetDef object. This is done to make it easier to figure out
      when a virtualPortProfile has/hasn't been specified in a particular
      config.
      524655ee
  10. 21 7月, 2011 1 次提交
  11. 19 7月, 2011 1 次提交
    • E
      libvirt: do not mix internal flags into public API · 33ba6e68
      Eric Blake 提交于
      There were two API in driver.c that were silently masking flags
      bits prior to calling out to the drivers, and several others
      that were explicitly masking flags bits.  This is not
      forward-compatible - if we ever have that many flags in the
      future, then talking to an old server that masks out the
      flags would be indistinguishable from talking to a new server
      that can honor the flag.  In general, libvirt.c should forward
      _all_ flags on to drivers, and only the drivers should reject
      unknown flags.
      
      In the case of virDrvSecretGetValue, the solution is to separate
      the internal driver callback function to have two parameters
      instead of one, with only one parameter affected by the public
      API.  In the case of virDomainGetXMLDesc, it turns out that
      no one was ever mixing VIR_DOMAIN_XML_INTERNAL_STATUS with
      the dumpxml path in the first place; that internal flag was
      only used in saving and restoring state files, which happened
      to be in functions internal to a single file, so there is no
      mixing of the internal flag with a public flags argument.
      Additionally, virDomainMemoryStats passed a flags argument
      over RPC, but not to the driver.
      
      * src/driver.h (VIR_DOMAIN_XML_FLAGS_MASK)
      (VIR_SECRET_GET_VALUE_FLAGS_MASK): Delete.
      (virDrvSecretGetValue): Separate out internal flags.
      (virDrvDomainMemoryStats): Provide missing flags argument.
      * src/driver.c (verify): Drop unused check.
      * src/conf/domain_conf.h (virDomainObjParseFile): Delete
      declaration.
      (virDomainXMLInternalFlags): Move...
      * src/conf/domain_conf.c: ...here.  Delete redundant include.
      (virDomainObjParseFile): Make static.
      * src/libvirt.c (virDomainGetXMLDesc, virSecretGetValue): Update
      clients.
      (virDomainMemoryPeek, virInterfaceGetXMLDesc)
      (virDomainMemoryStats, virDomainBlockPeek, virNetworkGetXMLDesc)
      (virStoragePoolGetXMLDesc, virStorageVolGetXMLDesc)
      (virNodeNumOfDevices, virNodeListDevices, virNWFilterGetXMLDesc):
      Don't mask unknown flags.
      * src/interface/netcf_driver.c (interfaceGetXMLDesc): Reject
      unknown flags.
      * src/secret/secret_driver.c (secretGetValue): Update clients.
      * src/remote/remote_driver.c (remoteSecretGetValue)
      (remoteDomainMemoryStats): Likewise.
      * src/qemu/qemu_process.c (qemuProcessGetVolumeQcowPassphrase):
      Likewise.
      * src/qemu/qemu_driver.c (qemudDomainMemoryStats): Likewise.
      * daemon/remote.c (remoteDispatchDomainMemoryStats): Likewise.
      33ba6e68
  12. 12 7月, 2011 2 次提交
    • D
      Implement code to attach to external QEMU instances. · 109efd79
      Daniel P. Berrange 提交于
      Given a PID, the QEMU driver reads /proc/$PID/cmdline and
      /proc/$PID/environ to get the configuration. This is fed
      into the ARGV->XML convertor to build an XML configuration
      for the process.
      
      /proc/$PID/exe is resolved to identify the full command
      binary path
      
      After checking for name/uuid uniqueness, an attempt is
      made to connect to the monitor socket. If successful
      then 'info status' and 'info kvm' are issued to determine
      whether the CPUs are running and if KVM is enabled.
      
      * src/qemu/qemu_driver.c: Implement virDomainQemuAttach
      * src/qemu/qemu_process.h, src/qemu/qemu_process.c: Add
        qemuProcessAttach to connect to the monitor of an
        existing QEMU process
      109efd79
    • M
      Add domain type checking · aa14709a
      Matthias Bolte 提交于
      The drivers were accepting domain configs without checking if those
      were actually meant for them. For example the LXC driver happily
      accepts configs with type QEMU.
      
      Add a check for the expected domain types to the virDomainDefParse*
      functions.
      aa14709a
  13. 11 7月, 2011 1 次提交
    • M
      bios: Add support for SGA · 874e65aa
      Michal Privoznik 提交于
      This patch creates new <bios> element which, at this time has only the
      attribute useserial='yes|no'. This attribute allow users to use
      Serial Graphics Adapter and see BIOS messages from the very first moment
      domain boots up. Therefore, users can choose boot medium, set PXE, etc.
      874e65aa
  14. 08 7月, 2011 1 次提交
  15. 06 7月, 2011 2 次提交
    • D
      Fix default value of security label 'relabel' attribute · 693eac38
      Daniel P. Berrange 提交于
      When no <seclabel> is present in the XML, the virDomainSeclabelDef
      struct is left as all zeros. Unfortunately, this means it gets setup
      as type=dynamic, with relabel=no, which is an illegal combination.
      
      Change the 'bool relabel' attribute in virDomainSeclabelDef to
      the inverse 'bool norelabel' so that the default initialization
      is sensible
      
      * src/conf/domain_conf.c, src/conf/domain_conf.h,
        src/security/security_apparmor.c, src/security/security_selinux.c:
        Replace 'relabel' with 'norelabel'
      693eac38
    • L
      conf: fix domain parse flags · d3f7c7b1
      Laine Stump 提交于
      * Change all flags args from int to unsigned int
      
      * Allow passing flags in virDomainObjParseFile (and propogate those
        flags all the way down the call chain). Previously the flags were
        hardcoded (to VIR_DOMAIN_XML_INTERNAL_STATUS) several layers down
        the chain. Pass that value in at the one place that is currently
        calling virDomainObjParseFile.
      d3f7c7b1
  16. 04 7月, 2011 2 次提交
    • D
      Allow for resource relabelling with static labels · 6321fd97
      Daniel P. Berrange 提交于
      Add a new attribute to the <seclabel> XML to allow resource
      relabelling to be enabled with static label usage.
      
        <seclabel model='selinux' type='static' relabel='yes'>
          <label>system_u:system_r:svirt_t:s0:c392,c662</label>
        </seclabel>
      
      * docs/schemas/domain.rng: Add relabel attribute
      * src/conf/domain_conf.c, src/conf/domain_conf.h: Parse
        the 'relabel' attribute
      * src/qemu/qemu_process.c: Unconditionally clear out the
        'imagelabel' attribute
      * src/security/security_apparmor.c: Skip based on 'relabel'
        attribute instead of label type
      * src/security/security_selinux.c: Skip based on 'relabel'
        attribute instead of label type and fill in <imagelabel>
        attribute if relabel is enabled.
      6321fd97
    • D
      Allow a base label to be specified in dynamic labelling mode · 4ebfc427
      Daniel P. Berrange 提交于
      Normally the dynamic labelling mode will always use a base
      label of 'svirt_t' for VMs. Introduce a <baselabel> field
      in the <seclabel> XML to allow this base label to be changed
      
      eg
      
         <seclabel type='dynamic' model='selinux'>
           <baselabel>system_u:object_r:virt_t:s0</baselabel>
         </seclabel>
      
      * docs/schemas/domain.rng: Add <baselabel>
      * src/conf/domain_conf.c, src/conf/domain_conf.h: Parsing
        of base label
      * src/qemu/qemu_process.c: Don't reset 'model' attribute if
        a base label is specified
      * src/security/security_apparmor.c: Refuse to support base label
      * src/security/security_selinux.c: Use 'baselabel' when generating
        label, if available
      4ebfc427
  17. 27 6月, 2011 1 次提交
    • E
      build: rename Vcpupin to VcpuPin · 28e45afc
      Eric Blake 提交于
      We already have a public virDomainPinVcpu, which implies that
      Pin and Vcpu are treated as separate words.  Unreleased commit
      e261987c introduced virDomainGetVcpupinInfo as the first public
      API that used Vcpupin, although we had prior internal uses of
      that spelling.  For consistency, change the spelling to be two
      words everywhere, regardless of whether pin comes first or last.
      
      * daemon/remote.c: Treat vcpu and pin as separate words.
      * include/libvirt/libvirt.h.in: Likewise.
      * src/conf/domain_conf.c: Likewise.
      * src/conf/domain_conf.h: Likewise.
      * src/driver.h: Likewise.
      * src/libvirt.c: Likewise.
      * src/libvirt_private.syms: Likewise.
      * src/libvirt_public.syms: Likewise.
      * src/libxl/libxl_driver.c: Likewise.
      * src/qemu/qemu_driver.c: Likewise.
      * src/remote/remote_driver.c: Likewise.
      * src/xen/xend_internal.c: Likewise.
      * tools/virsh.c: Likewise.
      * src/remote/remote_protocol.x: Likewise.
      * src/remote_protocol-structs: Likewise.
      Suggested by Matthias Bolte.
      28e45afc
  18. 23 6月, 2011 1 次提交
    • D
      Remove macvtap dependency on domain configuration · caf808c7
      Daniel P. Berrange 提交于
      Files under src/util must not depend on src/conf
      Solve the macvtap problem by moving the definition
      of macvtap modes from domain_conf.h into macvtap.h
      
      * src/util/macvtap.c, src/util/macvtap.h: Add enum
        for macvtap modes
      * src/conf/domain_conf.c, src/conf/domain_conf.h: Remove
        enum for macvtap modes
      caf808c7
  19. 22 6月, 2011 1 次提交
    • M
      qemu: domain I/O asynchronous handling · 017abcbb
      Michal Privoznik 提交于
      For virtio disks and interfaces, qemu allows users to enable or disable
      ioeventfd feature. This means, qemu can execute domain code, while
      another thread waits for I/O event. Basically, in some cases it is win,
      in some loss. This feature is available via 'ioeventfd' attribute in disk
      and interface <driver> element. It accepts 'on' and 'off'. Leaving this
      attribute out defaults to hypervisor decision.
      017abcbb
  20. 20 6月, 2011 2 次提交
  21. 15 6月, 2011 2 次提交
    • D
      support for Xen HVM Viridian (Hyper-V) enlightenment interface · c4bd6d96
      Daniel Gollub 提交于
      Introduce libvirt support for Xen HVM Viridian (Hyper-V) enlightenment
      interface guest feature.
      
       src/conf/domain_conf.c     |    3 ++-
       src/conf/domain_conf.h     |    1 +
       src/xen/xen_hypervisor.c   |   11 +++++++++++
       src/xenapi/xenapi_driver.c |    2 ++
       src/xenapi/xenapi_utils.c  |    2 ++
       src/xenxs/xen_sxpr.c       |    4 ++++
       src/xenxs/xen_xm.c         |   12 +++++++++++-
       7 files changed, 33 insertions(+), 2 deletions(-)
      c4bd6d96
    • M
      spice: add <clipboard copypaste='yes|no'> option · 98bfdff1
      Marc-André Lureau 提交于
      From a security pov copy and paste between the guest and the client is not
      always desirable. So we need to be able to enable/disable this. The best place
      to do this from an administration pov is on the hypervisor, so the qemu cmdline
      is getting a spice disable-copy-paste option, see bug 693645. Example qemu
      invocation:
      qemu -spice port=5932,disable-ticketing,disable-copy-paste
      
      https://bugzilla.redhat.com/show_bug.cgi?id=693661
      98bfdff1
  22. 02 6月, 2011 2 次提交
    • D
      Allow leases to be hotpluged with QEMU guests · 30ffe7bc
      Daniel P. Berrange 提交于
      * src/conf/domain_conf.c, src/conf/domain_conf.h: APIs for
        inserting/finding/removing virDomainLeaseDefPtr instances
      * src/qemu/qemu_driver.c: Wire up hotplug/unplug for leases
      * src/qemu/qemu_hotplug.h, src/qemu/qemu_hotplug.c: Support
        for hotplug and unplug of leases
      30ffe7bc
    • D
      Support leases in guest XML and lock manager · 1ea83207
      Daniel P. Berrange 提交于
      A lock manager may operate in various modes. The direct mode of
      operation is to obtain locks based on the resources associated
      with devices in the XML. The indirect mode is where the app
      creating the domain provides explicit leases for each resource
      that needs to be locked. This XML extension allows for listing
      resources in the XML
      
        <devices>
           ...
           <lease>
             <lockspace>somearea</lockspace>
             <key>thequickbrownfoxjumpsoverthelazydog</key>
             <target path='/some/lease/path' offset='23432'/>
           </lease>
           ...
        </devices>
      
      The 'lockspace' is a unique identifier for the lockspace which
      the lease is associated
      
      The 'key' is a unique identifier for the resource associated
      with the lease.
      
      The 'target' is the file on disk where the leases are held.
      
      * docs/schemas/domain.rng: Add lease schema
      * src/conf/domain_conf.c, src/conf/domain_conf.h: parsing and
        formatting for leases
      * tests/qemuxml2argvdata/qemuxml2argv-lease.args,
        tests/qemuxml2argvdata/qemuxml2argv-lease.xml,
        tests/qemuxml2xmltest.c: Test XML handling for leases
      1ea83207
  23. 31 5月, 2011 2 次提交
    • D
      Add an API for comparing the ABI of two guest configurations · 08106e20
      Daniel P. Berrange 提交于
      To allow a client app to pass in custom XML during migration
      of a guest it is neccessary to ensure the guest ABI remains
      unchanged. The virDomainDefCheckABIStablity method accepts
      two virDomainDefPtr structs and compares everything in them
      that could impact the guest machine ABI
      
      * src/conf/domain_conf.c, src/conf/domain_conf.h,
        src/libvirt_private.syms: Add virDomainDefCheckABIStablity
      * src/conf/cpu_conf.c, src/conf/cpu_conf.h: Add virCPUDefIsEqual
      * src/util/sysinfo.c, src/util/sysinfo.h: Add virSysinfoIsEqual
      08106e20
    • D
      Remove unused 'target' field in virDomainHostdevDef · 0e4d4afb
      Daniel P. Berrange 提交于
      The virDomainHostdevDef struct contains a 'char *target'
      field. This is set to 'NULL' when parsing XML and never
      used / set anywhere else. Clearly it is bogus & unused
      
      * src/conf/domain_conf.c, src/conf/domain_conf.h: Remove
        target from virDomainHostdevDef
      0e4d4afb
  24. 27 5月, 2011 1 次提交
    • K
      qemu : support persistent add/delete network interface · 9c26d6f0
      KAMEZAWA Hiroyuki 提交于
      This patch allows to modify interfaces of domain(qemu)
      * src/conf/domain_conf.c src/conf/domain_conf.h src/libvirt_private.syms:
        (virDomainNetInsert)     : Insert a network device to domain definition.
        (virDomainNetIndexByMac) : Returns an index of net device in array.
        (virDomainNetRemoveByMac): Remove a NIC of passed MAC address.
      * src/qemu/qemu_driver.c
        (qemuDomainAttachDeviceConfig): add codes for NIC.
        (qemuDomainDetachDeviceConfig): add codes for NIC.
      9c26d6f0
  25. 26 5月, 2011 1 次提交
  26. 24 5月, 2011 1 次提交
    • A
      spice: support streaming-video parameter · bb1c5423
      Alon Levy 提交于
      This adds a streaming-video=filter|all|off attribute. It is used to change
      the behavior of video stream detection in spice, the default is filter (the
      default for libvirt is not to specify it - the actual default is defined in
      libspice-server.so).
      
      Usage:
      
          <graphics type='spice' autoport='yes'>
            <streaming mode='off'/>
          </graphics>
      
      Tested with the above and with tests/qemuxml2argvtest.
      Signed-off-by: NAlon Levy <alevy@redhat.com>
      bb1c5423
  27. 18 5月, 2011 1 次提交
  28. 16 5月, 2011 1 次提交
    • J
      Implement domain state reason · b046c55d
      Jiri Denemark 提交于
      Only in drivers which use virDomainObj, drivers that query hypervisor
      for domain status need to be updated separately in case their hypervisor
      supports this functionality.
      
      The reason is also saved into domain state XML so if a domain is not
      running (i.e., no state XML exists) the reason will be lost by libvirtd
      restart. I think this is an acceptable limitation.
      b046c55d