(2.10) KVM: use running HVPs to calc blockdev options
[ganeti-local] / lib / hypervisor / hv_kvm.py
index e2f4599..de15a89 100644 (file)
@@ -60,7 +60,7 @@ from ganeti.hypervisor import hv_base
 from ganeti.utils import wrapper as utils_wrapper
 
 
-_KVM_NETWORK_SCRIPT = pathutils.CONF_DIR + "/kvm-vif-bridge"
+_KVM_NETWORK_SCRIPT = pathutils.CONF_DIR + "/kvm-ifup-custom"
 _KVM_START_PAUSED_FLAG = "-S"
 
 # TUN/TAP driver constants, taken from <linux/if_tun.h>
@@ -90,7 +90,8 @@ _AVAILABLE_PCI_SLOT = bitarray("0")
 
 # below constants show the format of runtime file
 # the nics are in second possition, while the disks in 4th (last)
-# moreover disk entries are stored in tupples of L{objects.Disk}, dev_path
+# moreover disk entries are stored as a list of in tuples
+# (L{objects.Disk}, link_name)
 _KVM_NICS_RUNTIME_INDEX = 1
 _KVM_DISKS_RUNTIME_INDEX = 3
 _DEVICE_RUNTIME_INDEX = {
@@ -113,8 +114,10 @@ _RUNTIME_ENTRY = {
   constants.HOTPLUG_TARGET_DISK: lambda d, e: (d, e)
   }
 
+_MIGRATION_CAPS_DELIM = ":"
 
-def _GenerateDeviceKVMId(dev_type, dev):
+
+def _GenerateDeviceKVMId(dev_type, dev, idx=None):
   """Helper function to generate a unique device name used by KVM
 
   QEMU monitor commands use names to identify devices. Here we use their pci
@@ -129,36 +132,49 @@ def _GenerateDeviceKVMId(dev_type, dev):
 
   """
 
-  if not dev.pci:
-    raise errors.HotplugError("Hotplug is not supported for %s with UUID %s" %
-                              (dev_type, dev.uuid))
+  # proper device id - available in latest Ganeti versions
+  if dev.pci and dev.uuid:
+    return "%s-%s-pci-%d" % (dev_type.lower(), dev.uuid.split("-")[0], dev.pci)
 
-  return "%s-%s-pci-%d" % (dev_type.lower(), dev.uuid.split("-")[0], dev.pci)
+  # dummy device id - returned only to _GenerateKVMBlockDevicesOptions
+  # This enables -device option for paravirtual disk_type
+  if idx is not None:
+    return "%s-%d" % (dev_type.lower(), idx)
 
+  raise errors.HotplugError("Hotplug is not supported for devices"
+                            " without UUID or PCI info")
 
-def _UpdatePCISlots(dev, pci_reservations):
-  """Update pci configuration for a stopped instance
 
-  If dev has a pci slot then reserve it, else find first available
-  in pci_reservations bitarray. It acts on the same objects passed
-  as params so there is no need to return anything.
+def _GetFreeSlot(slots, slot=None, reserve=False):
+  """Helper method to get first available slot in a bitarray
 
-  @type dev: L{objects.Disk} or L{objects.NIC}
-  @param dev: the device object for which we update its pci slot
-  @type pci_reservations: bitarray
-  @param pci_reservations: existing pci reservations for an instance
-  @raise errors.HotplugError: in case an instance has all its slot occupied
+  @type slots: bitarray
+  @param slots: the bitarray to operate on
+  @type slot: integer
+  @param slot: if given we check whether the slot is free
+  @type reserve: boolean
+  @param reserve: whether to reserve the first available slot or not
+  @return: the idx of the (first) available slot
+  @raise errors.HotplugError: If all slots in a bitarray are occupied
+    or the given slot is not free.
 
   """
-  if dev.pci:
-    free = dev.pci
-  else: # pylint: disable=E1103
-    [free] = pci_reservations.search(_AVAILABLE_PCI_SLOT, 1)
-    if not free:
-      raise errors.HypervisorError("All PCI slots occupied")
-    dev.pci = int(free)
+  if slot is not None:
+    assert slot < len(slots)
+    if slots[slot]:
+      raise errors.HypervisorError("Slots %d occupied" % slot)
+
+  else:
+    avail = slots.search(_AVAILABLE_PCI_SLOT, 1)
+    if not avail:
+      raise errors.HypervisorError("All slots occupied")
+
+    slot = int(avail[0])
 
-  pci_reservations[free] = True
+  if reserve:
+    slots[slot] = True
+
+  return slot
 
 
 def _GetExistingDeviceInfo(dev_type, device, runtime):
@@ -187,27 +203,50 @@ def _GetExistingDeviceInfo(dev_type, device, runtime):
   return found[0]
 
 
-def _AnalyzeSerializedRuntime(serialized_runtime):
-  """Return runtime entries for a serialized runtime file
+def _UpgradeSerializedRuntime(serialized_runtime):
+  """Upgrade runtime data
+
+  Remove any deprecated fields or change the format of the data.
+  The runtime files are not upgraded when Ganeti is upgraded, so the required
+  modification have to be performed here.
 
   @type serialized_runtime: string
   @param serialized_runtime: raw text data read from actual runtime file
-  @return: (cmd, nics, hvparams, bdevs)
-  @rtype: list
+  @return: (cmd, nic dicts, hvparams, bdev dicts)
+  @rtype: tuple
 
   """
   loaded_runtime = serializer.Load(serialized_runtime)
-  if len(loaded_runtime) == 3:
-    serialized_blockdevs = []
-    kvm_cmd, serialized_nics, hvparams = loaded_runtime
+  kvm_cmd, serialized_nics, hvparams = loaded_runtime[:3]
+  if len(loaded_runtime) >= 4:
+    serialized_disks = loaded_runtime[3]
   else:
-    kvm_cmd, serialized_nics, hvparams, serialized_blockdevs = loaded_runtime
+    serialized_disks = []
+
+  for nic in serialized_nics:
+    # Add a dummy uuid slot if an pre-2.8 NIC is found
+    if "uuid" not in nic:
+      nic["uuid"] = utils.NewUUID()
+
+  return kvm_cmd, serialized_nics, hvparams, serialized_disks
+
+
+def _AnalyzeSerializedRuntime(serialized_runtime):
+  """Return runtime entries for a serialized runtime file
 
+  @type serialized_runtime: string
+  @param serialized_runtime: raw text data read from actual runtime file
+  @return: (cmd, nics, hvparams, bdevs)
+  @rtype: tuple
+
+  """
+  kvm_cmd, serialized_nics, hvparams, serialized_disks = \
+    _UpgradeSerializedRuntime(serialized_runtime)
   kvm_nics = [objects.NIC.FromDict(snic) for snic in serialized_nics]
-  block_devices = [(objects.Disk.FromDict(sdisk), link)
-                   for sdisk, link in serialized_blockdevs]
+  kvm_disks = [(objects.Disk.FromDict(sdisk), link)
+               for sdisk, link in serialized_disks]
 
-  return (kvm_cmd, kvm_nics, hvparams, block_devices)
+  return (kvm_cmd, kvm_nics, hvparams, kvm_disks)
 
 
 def _GetTunFeatures(fd, _ioctl=fcntl.ioctl):
@@ -426,7 +465,6 @@ class QmpConnection(MonitorSocket):
   _RETURN_KEY = RETURN_KEY = "return"
   _ACTUAL_KEY = ACTUAL_KEY = "actual"
   _ERROR_CLASS_KEY = "class"
-  _ERROR_DATA_KEY = "data"
   _ERROR_DESC_KEY = "desc"
   _EXECUTE_KEY = "execute"
   _ARGUMENTS_KEY = "arguments"
@@ -456,6 +494,10 @@ class QmpConnection(MonitorSocket):
       raise errors.HypervisorError("kvm: QMP communication error (wrong"
                                    " server greeting")
 
+    # This is needed because QMP can return more than one greetings
+    # see https://groups.google.com/d/msg/ganeti-devel/gZYcvHKDooU/SnukC8dgS5AJ
+    self._buf = ""
+
     # Let's put the monitor in command mode using the qmp_capabilities
     # command, or else no command will be executable.
     # (As per the QEMU Protocol Specification 0.1 - section 4)
@@ -570,11 +612,10 @@ class QmpConnection(MonitorSocket):
       err = response[self._ERROR_KEY]
       if err:
         raise errors.HypervisorError("kvm: error executing the %s"
-                                     " command: %s (%s, %s):" %
+                                     " command: %s (%s):" %
                                      (command,
                                       err[self._ERROR_DESC_KEY],
-                                      err[self._ERROR_CLASS_KEY],
-                                      err[self._ERROR_DATA_KEY]))
+                                      err[self._ERROR_CLASS_KEY]))
 
       elif not response[self._EVENT_KEY]:
         return response
@@ -663,6 +704,7 @@ class KVMHypervisor(hv_base.BaseHypervisor):
     constants.HV_MIGRATION_BANDWIDTH: hv_base.REQ_NONNEGATIVE_INT_CHECK,
     constants.HV_MIGRATION_DOWNTIME: hv_base.REQ_NONNEGATIVE_INT_CHECK,
     constants.HV_MIGRATION_MODE: hv_base.MIGRATION_MODE_CHECK,
+    constants.HV_KVM_MIGRATION_CAPS: hv_base.NO_CHECK,
     constants.HV_USE_LOCALTIME: hv_base.NO_CHECK,
     constants.HV_DISK_CACHE:
       hv_base.ParamInSet(True, constants.HT_VALID_CACHE_TYPES),
@@ -730,11 +772,18 @@ class KVMHypervisor(hv_base.BaseHypervisor):
 
   _INFO_PCI_RE = re.compile(r'Bus.*device[ ]*(\d+).*')
   _INFO_PCI_CMD = "info pci"
+  _FIND_PCI_DEVICE_RE = \
+    staticmethod(lambda pci, devid:
+      re.compile(r'Bus.*device[ ]*%d,(.*\n){5,6}.*id "%s"' % (pci, devid),
+                 re.M))
+
   _INFO_VERSION_RE = \
     re.compile(r'^QEMU (\d+)\.(\d+)(\.(\d+))?.*monitor.*', re.M)
   _INFO_VERSION_CMD = "info version"
 
-  _DEFAULT_PCI_RESERVATIONS = "11110000000000000000000000000000"
+  # Slot 0 for Host bridge, Slot 1 for ISA bridge, Slot 2 for VGA controller
+  _DEFAULT_PCI_RESERVATIONS = "11100000000000000000000000000000"
+  _SOUNDHW_WITH_PCI_SLOT = ["ac97", "es1370", "hda"]
 
   ANCILLARY_FILES = [
     _KVM_NETWORK_SCRIPT,
@@ -908,11 +957,40 @@ class KVMHypervisor(hv_base.BaseHypervisor):
     return utils.PathJoin(cls._NICS_DIR, instance_name)
 
   @classmethod
-  def _InstanceNICFile(cls, instance_name, seq):
+  def _InstanceNICFile(cls, instance_name, seq_or_uuid):
     """Returns the name of the file containing the tap device for a given NIC
 
     """
-    return utils.PathJoin(cls._InstanceNICDir(instance_name), str(seq))
+    return utils.PathJoin(cls._InstanceNICDir(instance_name), str(seq_or_uuid))
+
+  @classmethod
+  def _GetInstanceNICTap(cls, instance_name, nic):
+    """Returns the tap for the corresponding nic
+
+    Search for tap file named after NIC's uuid.
+    For old instances without uuid indexed tap files returns nothing.
+
+    """
+    try:
+      return utils.ReadFile(cls._InstanceNICFile(instance_name, nic.uuid))
+    except EnvironmentError:
+      pass
+
+  @classmethod
+  def _WriteInstanceNICFiles(cls, instance_name, seq, nic, tap):
+    """Write tap name to both instance NIC files
+
+    """
+    for ident in [seq, nic.uuid]:
+      utils.WriteFile(cls._InstanceNICFile(instance_name, ident), data=tap)
+
+  @classmethod
+  def _RemoveInstanceNICFiles(cls, instance_name, seq, nic):
+    """Write tap name to both instance NIC files
+
+    """
+    for ident in [seq, nic.uuid]:
+      utils.RemoveFile(cls._InstanceNICFile(instance_name, ident))
 
   @classmethod
   def _InstanceKeymapFile(cls, instance_name):
@@ -941,6 +1019,8 @@ class KVMHypervisor(hv_base.BaseHypervisor):
     """Removes an instance's rutime sockets/files/dirs.
 
     """
+    # This takes info from NICDir and RuntimeFile
+    cls._UnconfigureInstanceNICs(instance_name)
     utils.RemoveFile(pidfile)
     utils.RemoveFile(cls._InstanceMonitor(instance_name))
     utils.RemoveFile(cls._InstanceSerial(instance_name))
@@ -977,37 +1057,40 @@ class KVMHypervisor(hv_base.BaseHypervisor):
         raise
 
   @staticmethod
-  def _ConfigureNIC(instance, seq, nic, tap):
-    """Run the network configuration script for a specified NIC
+  def _CreateNICEnv(instance_name, nic, tap, seq=None, instance_tags=None):
+    """Create environment variables for a specific NIC
 
-    @param instance: instance we're acting on
-    @type instance: instance object
-    @param seq: nic sequence number
-    @type seq: int
-    @param nic: nic we're acting on
-    @type nic: nic object
-    @param tap: the host's tap interface this NIC corresponds to
-    @type tap: str
+    This is needed during NIC ifup/ifdown scripts.
+    Since instance tags may change during NIC creation and removal
+    and because during cleanup instance object is not available we
+    pass them only upon NIC creation (instance startup/NIC hot-plugging).
 
     """
-    if instance.tags:
-      tags = " ".join(instance.tags)
-    else:
-      tags = ""
-
     env = {
       "PATH": "%s:/sbin:/usr/sbin" % os.environ["PATH"],
-      "INSTANCE": instance.name,
+      "INSTANCE": instance_name,
       "MAC": nic.mac,
       "MODE": nic.nicparams[constants.NIC_MODE],
-      "INTERFACE": tap,
-      "INTERFACE_INDEX": str(seq),
-      "TAGS": tags,
+      "INTERFACE_UUID": nic.uuid,
     }
 
+    if instance_tags:
+      env["TAGS"] = " ".join(instance_tags)
+
+    # This should always be available except for old instances in the
+    # cluster without uuid indexed tap files.
+    if tap:
+      env["INTERFACE"] = tap
+
+    if seq:
+      env["INTERFACE_INDEX"] = str(seq)
+
     if nic.ip:
       env["IP"] = nic.ip
 
+    if nic.name:
+      env["INTERFACE_NAME"] = nic.name
+
     if nic.nicparams[constants.NIC_LINK]:
       env["LINK"] = nic.nicparams[constants.NIC_LINK]
 
@@ -1018,12 +1101,52 @@ class KVMHypervisor(hv_base.BaseHypervisor):
     if nic.nicparams[constants.NIC_MODE] == constants.NIC_MODE_BRIDGED:
       env["BRIDGE"] = nic.nicparams[constants.NIC_LINK]
 
+    return env
+
+  @classmethod
+  def _ConfigureNIC(cls, instance, seq, nic, tap):
+    """Run the network configuration script for a specified NIC
+
+    @param instance: instance we're acting on
+    @type instance: instance object
+    @param seq: nic sequence number
+    @type seq: int
+    @param nic: nic we're acting on
+    @type nic: nic object
+    @param tap: the host's tap interface this NIC corresponds to
+    @type tap: str
+
+    """
+    env = cls._CreateNICEnv(instance.name, nic, tap, seq, instance.GetTags())
     result = utils.RunCmd([pathutils.KVM_IFUP, tap], env=env)
     if result.failed:
       raise errors.HypervisorError("Failed to configure interface %s: %s;"
                                    " network configuration script output: %s" %
                                    (tap, result.fail_reason, result.output))
 
+  @classmethod
+  def _UnconfigureNic(cls, instance_name, nic, only_local=True):
+    """Run ifdown script for a specific NIC
+
+    This is executed during instance cleanup and NIC hot-unplug
+
+    @param instance: instance we're acting on
+    @type instance: instance object
+    @param nic: nic we're acting on
+    @type nic: nic object
+    @param localy: whether ifdown script should reset global conf (dns) or not
+    @type localy: boolean
+
+    """
+    tap = cls._GetInstanceNICTap(instance_name, nic)
+    env = cls._CreateNICEnv(instance_name, nic, tap)
+    arg2 = str(only_local).lower()
+    result = utils.RunCmd([pathutils.KVM_IFDOWN, tap, arg2], env=env)
+    if result.failed:
+      raise errors.HypervisorError("Failed to unconfigure interface %s: %s;"
+                                   " network configuration script output: %s" %
+                                   (tap, result.fail_reason, result.output))
+
   @staticmethod
   def _VerifyAffinityPackage():
     if affinity is None:
@@ -1184,11 +1307,29 @@ class KVMHypervisor(hv_base.BaseHypervisor):
         data.append(info)
     return data
 
-  def _GenerateKVMBlockDevicesOptions(self, instance, block_devices, kvmhelp):
+  def _GenerateKVMBlockDevicesOptions(self, instance, up_hvp, kvm_disks,
+                                      kvmhelp, devlist):
+    """Generate KVM options regarding instance's block devices.
 
-    hvp = instance.hvparams
-    boot_disk = hvp[constants.HV_BOOT_ORDER] == constants.HT_BO_DISK
-    kvm_path = hvp[constants.HV_KVM_PATH]
+    @type instance: L{objects.Instance}
+    @param instance: the instance object
+    @type up_hvp: dict
+    @param up_hvp: the instance's runtime hypervisor parameters
+    @type kvm_disks: list of tuples
+    @param kvm_disks: list of tuples [(disk, link_name)..]
+    @type kvmhelp: string
+    @param kvmhelp: output of kvm --help
+    @type devlist: string
+    @param devlist: output of kvm -device ?
+    @rtype: list
+    @return: list of command line options eventually used by kvm executable
+
+    """
+    kernel_path = up_hvp[constants.HV_KERNEL_PATH]
+    if kernel_path:
+      boot_disk = False
+    else:
+      boot_disk = up_hvp[constants.HV_BOOT_ORDER] == constants.HT_BO_DISK
 
     # whether this is an older KVM version that uses the boot=on flag
     # on devices
@@ -1196,11 +1337,10 @@ class KVMHypervisor(hv_base.BaseHypervisor):
 
     dev_opts = []
     device_driver = None
-    disk_type = hvp[constants.HV_DISK_TYPE]
+    disk_type = up_hvp[constants.HV_DISK_TYPE]
     if disk_type == constants.HT_DISK_PARAVIRTUAL:
       if_val = ",if=%s" % self._VIRTIO
       try:
-        devlist = self._GetKVMOutput(kvm_path, self._KVMOPT_DEVICELIST)
         if self._VIRTIO_BLK_RE.search(devlist):
           if_val = ",if=none"
           # will be passed in -device option as driver
@@ -1210,7 +1350,7 @@ class KVMHypervisor(hv_base.BaseHypervisor):
     else:
       if_val = ",if=%s" % disk_type
     # Cache mode
-    disk_cache = hvp[constants.HV_DISK_CACHE]
+    disk_cache = up_hvp[constants.HV_DISK_CACHE]
     if instance.disk_template in constants.DTS_EXT_MIRROR:
       if disk_cache != "none":
         # TODO: make this a hard error, instead of a silent overwrite
@@ -1222,7 +1362,7 @@ class KVMHypervisor(hv_base.BaseHypervisor):
       cache_val = ",cache=%s" % disk_cache
     else:
       cache_val = ""
-    for cfdev, dev_path in block_devices:
+    for idx, (cfdev, link_name) in enumerate(kvm_disks):
       if cfdev.mode != constants.DISK_RDWR:
         raise errors.HypervisorError("Instance has read-only disks which"
                                      " are not supported by KVM")
@@ -1233,21 +1373,43 @@ class KVMHypervisor(hv_base.BaseHypervisor):
         boot_disk = False
         if needs_boot_flag and disk_type != constants.HT_DISK_IDE:
           boot_val = ",boot=on"
+
+      # For ext we allow overriding disk_cache hypervisor params per disk
+      disk_cache = cfdev.params.get("cache", None)
+      if disk_cache:
+        cache_val = ",cache=%s" % disk_cache
       drive_val = "file=%s,format=raw%s%s%s" % \
-                  (dev_path, if_val, boot_val, cache_val)
+                  (link_name, if_val, boot_val, cache_val)
 
       if device_driver:
-        # block_devices are the 4th entry of runtime file that did not exist in
+        # kvm_disks are the 4th entry of runtime file that did not exist in
         # the past. That means that cfdev should always have pci slot and
         # _GenerateDeviceKVMId() will not raise a exception.
-        kvm_devid = _GenerateDeviceKVMId(constants.HOTPLUG_TARGET_DISK, cfdev)
+        kvm_devid = _GenerateDeviceKVMId(constants.HOTPLUG_TARGET_DISK,
+                                         cfdev, idx)
         drive_val += (",id=%s" % kvm_devid)
-        drive_val += (",bus=0,unit=%d" % cfdev.pci)
+        if cfdev.pci:
+          drive_val += (",bus=0,unit=%d" % cfdev.pci)
         dev_val = ("%s,drive=%s,id=%s" %
                    (device_driver, kvm_devid, kvm_devid))
-        dev_val += ",bus=pci.0,addr=%s" % hex(cfdev.pci)
+        if cfdev.pci:
+          dev_val += ",bus=pci.0,addr=%s" % hex(cfdev.pci)
         dev_opts.extend(["-device", dev_val])
 
+      # TODO: export disk geometry in IDISK_PARAMS
+      heads = cfdev.params.get('heads', None)
+      secs = cfdev.params.get('secs', None)
+      if heads and secs:
+        nr_sectors = cfdev.size * 1024 * 1024 / 512
+        cyls = nr_sectors / (int(heads) * int(secs))
+        if cyls > 16383:
+          cyls = 16383
+        elif cyls < 2:
+          cyls = 2
+        if cyls and heads and secs:
+          drive_val += (",cyls=%d,heads=%d,secs=%d" %
+                        (cyls, int(heads), int(secs)))
+
       dev_opts.extend(["-drive", drive_val])
 
     return dev_opts
@@ -1288,7 +1450,27 @@ class KVMHypervisor(hv_base.BaseHypervisor):
     kvm_cmd.extend(["-smp", ",".join(smp_list)])
 
     kvm_cmd.extend(["-pidfile", pidfile])
-    kvm_cmd.extend(["-balloon", "virtio"])
+
+    pci_reservations = bitarray(self._DEFAULT_PCI_RESERVATIONS)
+
+    # As requested by music lovers
+    if hvp[constants.HV_SOUNDHW]:
+      soundhw = hvp[constants.HV_SOUNDHW]
+      # For some reason only few sound devices require a PCI slot
+      # while the Audio controller *must* be in slot 3.
+      # That's why we bridge this option early in command line
+      if soundhw in self._SOUNDHW_WITH_PCI_SLOT:
+        _ = _GetFreeSlot(pci_reservations, reserve=True)
+      kvm_cmd.extend(["-soundhw", soundhw])
+
+    if hvp[constants.HV_DISK_TYPE] == constants.HT_DISK_SCSI:
+      # The SCSI controller requires another PCI slot.
+      _ = _GetFreeSlot(pci_reservations, reserve=True)
+
+    # Add id to ballon and place to the first available slot (3 or 4)
+    addr = _GetFreeSlot(pci_reservations, reserve=True)
+    pci_info = ",bus=pci.0,addr=%s" % hex(addr)
+    kvm_cmd.extend(["-balloon", "virtio,id=balloon%s" % pci_info])
     kvm_cmd.extend(["-daemonize"])
     if not instance.hvparams[constants.HV_ACPI]:
       kvm_cmd.extend(["-no-acpi"])
@@ -1541,7 +1723,9 @@ class KVMHypervisor(hv_base.BaseHypervisor):
       else:
         # Enable the spice agent communication channel between the host and the
         # agent.
-        kvm_cmd.extend(["-device", "virtio-serial-pci"])
+        addr = _GetFreeSlot(pci_reservations, reserve=True)
+        pci_info = ",bus=pci.0,addr=%s" % hex(addr)
+        kvm_cmd.extend(["-device", "virtio-serial-pci,id=spice%s" % pci_info])
         kvm_cmd.extend([
           "-device",
           "virtserialport,chardev=spicechannel0,name=com.redhat.spice.0",
@@ -1569,10 +1753,6 @@ class KVMHypervisor(hv_base.BaseHypervisor):
     if hvp[constants.HV_CPU_TYPE]:
       kvm_cmd.extend(["-cpu", hvp[constants.HV_CPU_TYPE]])
 
-    # As requested by music lovers
-    if hvp[constants.HV_SOUNDHW]:
-      kvm_cmd.extend(["-soundhw", hvp[constants.HV_SOUNDHW]])
-
     # Pass a -vga option if requested, or if spice is used, for backwards
     # compatibility.
     if hvp[constants.HV_VGA]:
@@ -1588,15 +1768,14 @@ class KVMHypervisor(hv_base.BaseHypervisor):
     if hvp[constants.HV_KVM_EXTRA]:
       kvm_cmd.extend(hvp[constants.HV_KVM_EXTRA].split(" "))
 
-    pci_reservations = bitarray(self._DEFAULT_PCI_RESERVATIONS)
     kvm_disks = []
     for disk, link_name in block_devices:
-      _UpdatePCISlots(disk, pci_reservations)
+      disk.pci = _GetFreeSlot(pci_reservations, disk.pci, True)
       kvm_disks.append((disk, link_name))
 
     kvm_nics = []
     for nic in instance.nics:
-      _UpdatePCISlots(nic, pci_reservations)
+      nic.pci = _GetFreeSlot(pci_reservations, nic.pci, True)
       kvm_nics.append(nic)
 
     hvparams = hvp
@@ -1613,12 +1792,13 @@ class KVMHypervisor(hv_base.BaseHypervisor):
     except EnvironmentError, err:
       raise errors.HypervisorError("Failed to save KVM runtime file: %s" % err)
 
-  def _ReadKVMRuntime(self, instance_name):
+  @classmethod
+  def _ReadKVMRuntime(cls, instance_name):
     """Read an instance's KVM runtime
 
     """
     try:
-      file_content = utils.ReadFile(self._InstanceKVMRuntime(instance_name))
+      file_content = utils.ReadFile(cls._InstanceKVMRuntime(instance_name))
     except EnvironmentError, err:
       raise errors.HypervisorError("Failed to load KVM runtime file: %s" % err)
     return file_content
@@ -1627,22 +1807,23 @@ class KVMHypervisor(hv_base.BaseHypervisor):
     """Save an instance's KVM runtime
 
     """
-    kvm_cmd, kvm_nics, hvparams, block_devices = kvm_runtime
+    kvm_cmd, kvm_nics, hvparams, kvm_disks = kvm_runtime
 
     serialized_nics = [nic.ToDict() for nic in kvm_nics]
-    serialized_blockdevs = [(blk.ToDict(), link)
-                            for blk, link in block_devices]
+    serialized_disks = [(blk.ToDict(), link)
+                            for blk, link in kvm_disks]
     serialized_form = serializer.Dump((kvm_cmd, serialized_nics, hvparams,
-                                      serialized_blockdevs))
+                                      serialized_disks))
 
     self._WriteKVMRuntime(instance.name, serialized_form)
 
-  def _LoadKVMRuntime(self, instance, serialized_runtime=None):
+  @classmethod
+  def _LoadKVMRuntime(cls, instance_name, serialized_runtime=None):
     """Load an instance's KVM runtime
 
     """
     if not serialized_runtime:
-      serialized_runtime = self._ReadKVMRuntime(instance.name)
+      serialized_runtime = cls._ReadKVMRuntime(instance_name)
 
     return _AnalyzeSerializedRuntime(serialized_runtime)
 
@@ -1669,7 +1850,7 @@ class KVMHypervisor(hv_base.BaseHypervisor):
     if not self._InstancePidAlive(name)[2]:
       raise errors.HypervisorError("Failed to start instance %s" % name)
 
-  # 52/50 local variables
+  # too many local variables
   # pylint: disable=R0914
   def _ExecuteKVMRuntime(self, instance, kvm_runtime, kvmhelp, incoming=None):
     """Execute a KVM cmd, after completing it with some last minute data.
@@ -1694,7 +1875,7 @@ class KVMHypervisor(hv_base.BaseHypervisor):
 
     temp_files = []
 
-    kvm_cmd, kvm_nics, up_hvp, block_devices = kvm_runtime
+    kvm_cmd, kvm_nics, up_hvp, kvm_disks = kvm_runtime
     # the first element of kvm_cmd is always the path to the kvm binary
     kvm_path = kvm_cmd[0]
     up_hvp = objects.FillDict(conf_hvp, up_hvp)
@@ -1720,6 +1901,15 @@ class KVMHypervisor(hv_base.BaseHypervisor):
     # related parameters we'll use up_hvp
     tapfds = []
     taps = []
+    devlist = self._GetKVMOutput(kvm_path, self._KVMOPT_DEVICELIST)
+
+    bdev_opts = self._GenerateKVMBlockDevicesOptions(instance,
+                                                     up_hvp,
+                                                     kvm_disks,
+                                                     kvmhelp,
+                                                     devlist)
+    kvm_cmd.extend(bdev_opts)
+
     if not kvm_nics:
       kvm_cmd.extend(["-net", "none"])
     else:
@@ -1729,7 +1919,6 @@ class KVMHypervisor(hv_base.BaseHypervisor):
       if nic_type == constants.HT_NIC_PARAVIRTUAL:
         nic_model = self._VIRTIO
         try:
-          devlist = self._GetKVMOutput(kvm_path, self._KVMOPT_DEVICELIST)
           if self._VIRTIO_NET_RE.search(devlist):
             nic_model = self._VIRTIO_NET_PCI
             vnet_hdr = up_hvp[constants.HV_VNET_HDR]
@@ -1808,10 +1997,6 @@ class KVMHypervisor(hv_base.BaseHypervisor):
         continue
       self._ConfigureNIC(instance, nic_seq, nic, taps[nic_seq])
 
-    bdev_opts = self._GenerateKVMBlockDevicesOptions(instance,
-                                                     block_devices,
-                                                     kvmhelp)
-    kvm_cmd.extend(bdev_opts)
     # CPU affinity requires kvm to start paused, so we set this flag if the
     # instance is not already paused and if we are not going to accept a
     # migrating instance. In the latter case, pausing is not needed.
@@ -1847,8 +2032,8 @@ class KVMHypervisor(hv_base.BaseHypervisor):
     utils.EnsureDirs([(self._InstanceNICDir(instance.name),
                      constants.RUN_DIRS_MODE)])
     for nic_seq, tap in enumerate(taps):
-      utils.WriteFile(self._InstanceNICFile(instance.name, nic_seq),
-                      data=tap)
+      nic = kvm_nics[nic_seq]
+      self._WriteInstanceNICFiles(instance.name, nic_seq, nic, tap)
 
     if vnc_pwd:
       change_cmd = "change vnc password %s" % vnc_pwd
@@ -1949,32 +2134,18 @@ class KVMHypervisor(hv_base.BaseHypervisor):
         slot = int(match.group(1))
         slots[slot] = True
 
-    [free] = slots.search(_AVAILABLE_PCI_SLOT, 1) # pylint: disable=E1101
-    if not free:
-      raise errors.HypervisorError("All PCI slots occupied")
+    dev.pci = _GetFreeSlot(slots)
 
-    dev.pci = int(free)
-
-  def HotplugSupported(self, instance, action, dev_type):
-    """Check if hotplug is supported.
+  def VerifyHotplugSupport(self, instance, action, dev_type):
+    """Verifies that hotplug is supported.
 
     Hotplug is *not* supported in case of:
-     - qemu versions < 1.0
      - security models and chroot (disk hotplug)
      - fdsend module is missing (nic hot-add)
 
-    @raise errors.HypervisorError: in previous cases
+    @raise errors.HypervisorError: in one of the previous cases
 
     """
-    output = self._CallMonitorCommand(instance.name, self._INFO_VERSION_CMD)
-    # TODO: search for netdev_add, drive_add, device_add.....
-    match = self._INFO_VERSION_RE.search(output.stdout)
-    if not match:
-      raise errors.HotplugError("Try hotplug only in running instances.")
-    v_major, v_min, _, _ = match.groups()
-    if (int(v_major), int(v_min)) < (1, 0):
-      raise errors.HotplugError("Hotplug not supported for qemu versions < 1.0")
-
     if dev_type == constants.HOTPLUG_TARGET_DISK:
       hvp = instance.hvparams
       security_model = hvp[constants.HV_SECURITY_MODEL]
@@ -1990,13 +2161,59 @@ class KVMHypervisor(hv_base.BaseHypervisor):
         action == constants.HOTPLUG_ACTION_ADD and not fdsend):
       raise errors.HotplugError("Cannot hot-add NIC."
                                 " fdsend python module is missing.")
-    return True
 
-  def _CallHotplugCommand(self, name, cmd):
-    output = self._CallMonitorCommand(name, cmd)
-    # TODO: parse output and check if succeeded
-    for line in output.stdout.splitlines():
-      logging.info("%s", line)
+  def HotplugSupported(self, instance):
+    """Checks if hotplug is generally supported.
+
+    Hotplug is *not* supported in case of:
+     - qemu versions < 1.0
+     - for stopped instances
+
+    @raise errors.HypervisorError: in one of the previous cases
+
+    """
+    try:
+      output = self._CallMonitorCommand(instance.name, self._INFO_VERSION_CMD)
+    except errors.HypervisorError:
+      raise errors.HotplugError("Instance is probably down")
+
+    # TODO: search for netdev_add, drive_add, device_add.....
+    match = self._INFO_VERSION_RE.search(output.stdout)
+    if not match:
+      raise errors.HotplugError("Cannot parse qemu version via monitor")
+
+    v_major, v_min, _, _ = match.groups()
+    if (int(v_major), int(v_min)) < (1, 0):
+      raise errors.HotplugError("Hotplug not supported for qemu versions < 1.0")
+
+  def _CallHotplugCommands(self, name, cmds):
+    for c in cmds:
+      self._CallMonitorCommand(name, c)
+      time.sleep(1)
+
+  def _VerifyHotplugCommand(self, instance_name, device, dev_type,
+                            should_exist):
+    """Checks if a previous hotplug command has succeeded.
+
+    It issues info pci monitor command and checks depending on should_exist
+    value if an entry with PCI slot and device ID is found or not.
+
+    @raise errors.HypervisorError: if result is not the expected one
+
+    """
+    output = self._CallMonitorCommand(instance_name, self._INFO_PCI_CMD)
+    kvm_devid = _GenerateDeviceKVMId(dev_type, device)
+    match = \
+      self._FIND_PCI_DEVICE_RE(device.pci, kvm_devid).search(output.stdout)
+    if match and not should_exist:
+      msg = "Device %s should have been removed but is still there" % kvm_devid
+      raise errors.HypervisorError(msg)
+
+    if not match and should_exist:
+      msg = "Device %s should have been added but is missing" % kvm_devid
+      raise errors.HypervisorError(msg)
+
+    logging.info("Device %s has been correctly hot-plugged", kvm_devid)
 
   def HotAddDevice(self, instance, dev_type, device, extra, seq):
     """ Helper method to hot-add a new device
@@ -2009,23 +2226,24 @@ class KVMHypervisor(hv_base.BaseHypervisor):
     if device.pci is None:
       self._GetFreePCISlot(instance, device)
     kvm_devid = _GenerateDeviceKVMId(dev_type, device)
-    runtime = self._LoadKVMRuntime(instance)
+    runtime = self._LoadKVMRuntime(instance.name)
     if dev_type == constants.HOTPLUG_TARGET_DISK:
-      command = "drive_add dummy file=%s,if=none,id=%s,format=raw\n" % \
-                 (extra, kvm_devid)
-      command += ("device_add virtio-blk-pci,bus=pci.0,addr=%s,drive=%s,id=%s" %
-                  (hex(device.pci), kvm_devid, kvm_devid))
+      cmds = ["drive_add dummy file=%s,if=none,id=%s,format=raw" %
+                (extra, kvm_devid)]
+      cmds += ["device_add virtio-blk-pci,bus=pci.0,addr=%s,drive=%s,id=%s" %
+                (hex(device.pci), kvm_devid, kvm_devid)]
     elif dev_type == constants.HOTPLUG_TARGET_NIC:
       (tap, fd) = _OpenTap()
       self._ConfigureNIC(instance, seq, device, tap)
       self._PassTapFd(instance, fd, device)
-      command = "netdev_add tap,id=%s,fd=%s\n" % (kvm_devid, kvm_devid)
+      cmds = ["netdev_add tap,id=%s,fd=%s" % (kvm_devid, kvm_devid)]
       args = "virtio-net-pci,bus=pci.0,addr=%s,mac=%s,netdev=%s,id=%s" % \
                (hex(device.pci), device.mac, kvm_devid, kvm_devid)
-      command += "device_add %s" % args
-      utils.WriteFile(self._InstanceNICFile(instance.name, seq), data=tap)
+      cmds += ["device_add %s" % args]
+      self._WriteInstanceNICFiles(instance.name, seq, device, tap)
 
-    self._CallHotplugCommand(instance.name, command)
+    self._CallHotplugCommands(instance.name, cmds)
+    self._VerifyHotplugCommand(instance.name, device, dev_type, True)
     # update relevant entries in runtime file
     index = _DEVICE_RUNTIME_INDEX[dev_type]
     entry = _RUNTIME_ENTRY[dev_type](device, extra)
@@ -2039,17 +2257,20 @@ class KVMHypervisor(hv_base.BaseHypervisor):
     invokes the device specific method.
 
     """
-    runtime = self._LoadKVMRuntime(instance)
+    runtime = self._LoadKVMRuntime(instance.name)
     entry = _GetExistingDeviceInfo(dev_type, device, runtime)
     kvm_device = _RUNTIME_DEVICE[dev_type](entry)
     kvm_devid = _GenerateDeviceKVMId(dev_type, kvm_device)
     if dev_type == constants.HOTPLUG_TARGET_DISK:
-      command = "device_del %s" % kvm_devid
+      cmds = ["device_del %s" % kvm_devid]
+      cmds += ["drive_del %s" % kvm_devid]
     elif dev_type == constants.HOTPLUG_TARGET_NIC:
-      command = "device_del %s\n" % kvm_devid
-      command += "netdev_del %s" % kvm_devid
-      utils.RemoveFile(self._InstanceNICFile(instance.name, seq))
-    self._CallHotplugCommand(instance.name, command)
+      cmds = ["device_del %s" % kvm_devid]
+      cmds += ["netdev_del %s" % kvm_devid]
+      self._UnconfigureNic(instance.name, kvm_device, False)
+      self._RemoveInstanceNICFiles(instance.name, seq, device)
+    self._CallHotplugCommands(instance.name, cmds)
+    self._VerifyHotplugCommand(instance.name, kvm_device, dev_type, False)
     index = _DEVICE_RUNTIME_INDEX[dev_type]
     runtime[index].remove(entry)
     self._SaveKVMRuntime(instance, runtime)
@@ -2067,7 +2288,6 @@ class KVMHypervisor(hv_base.BaseHypervisor):
       # putting it back in the same pci slot
       device.pci = self.HotDelDevice(instance, dev_type, device, _, seq)
       # TODO: remove sleep when socat gets removed
-      time.sleep(2)
       self.HotAddDevice(instance, dev_type, device, _, seq)
 
   def _PassTapFd(self, instance, fd, nic):
@@ -2175,6 +2395,15 @@ class KVMHypervisor(hv_base.BaseHypervisor):
       else:
         self._CallMonitorCommand(name, "system_powerdown", timeout)
 
+  @classmethod
+  def _UnconfigureInstanceNICs(cls, instance_name, info=None):
+    """Get runtime NICs of an instance and unconfigure them
+
+    """
+    _, kvm_nics, __, ___ = cls._LoadKVMRuntime(instance_name, info)
+    for nic in kvm_nics:
+      cls._UnconfigureNic(instance_name, nic)
+
   def CleanupInstance(self, instance_name):
     """Cleanup after a stopped instance
 
@@ -2197,7 +2426,7 @@ class KVMHypervisor(hv_base.BaseHypervisor):
                                    " not running" % instance.name)
     # StopInstance will delete the saved KVM runtime so:
     # ...first load it...
-    kvm_runtime = self._LoadKVMRuntime(instance)
+    kvm_runtime = self._LoadKVMRuntime(instance.name)
     # ...now we can safely call StopInstance...
     if not self.StopInstance(instance):
       self.StopInstance(instance, force=True)
@@ -2229,7 +2458,7 @@ class KVMHypervisor(hv_base.BaseHypervisor):
     @param target: target host (usually ip), on this node
 
     """
-    kvm_runtime = self._LoadKVMRuntime(instance, serialized_runtime=info)
+    kvm_runtime = self._LoadKVMRuntime(instance.name, serialized_runtime=info)
     incoming_address = (target, instance.hvparams[constants.HV_MIGRATION_PORT])
     kvmpath = instance.hvparams[constants.HV_KVM_PATH]
     kvmhelp = self._GetKVMOutput(kvmpath, self._KVMOPT_HELP)
@@ -2246,7 +2475,7 @@ class KVMHypervisor(hv_base.BaseHypervisor):
 
     """
     if success:
-      kvm_runtime = self._LoadKVMRuntime(instance, serialized_runtime=info)
+      kvm_runtime = self._LoadKVMRuntime(instance.name, serialized_runtime=info)
       kvm_nics = kvm_runtime[1]
 
       for nic_seq, nic in enumerate(kvm_nics):
@@ -2266,6 +2495,7 @@ class KVMHypervisor(hv_base.BaseHypervisor):
 
       self._WriteKVMRuntime(instance.name, info)
     else:
+      self._UnconfigureInstanceNICs(instance.name, info)
       self.StopInstance(instance, force=True)
 
   def MigrateInstance(self, instance, target, live):
@@ -2299,6 +2529,17 @@ class KVMHypervisor(hv_base.BaseHypervisor):
                        instance.hvparams[constants.HV_MIGRATION_DOWNTIME])
     self._CallMonitorCommand(instance_name, migrate_command)
 
+    # These commands are supported in latest qemu versions.
+    # Since _CallMonitorCommand does not catch monitor errors
+    # this does not raise an exception in case command is not supported
+    # TODO: either parse output of command or see if the command supported
+    # via info help (see hotplug)
+    migration_caps = instance.hvparams[constants.HV_KVM_MIGRATION_CAPS]
+    if migration_caps:
+      for c in migration_caps.split(_MIGRATION_CAPS_DELIM):
+        migrate_command = ("migrate_set_capability %s on" % c)
+        self._CallMonitorCommand(instance_name, migrate_command)
+
     migrate_command = "migrate -d tcp:%s:%s" % (target, port)
     self._CallMonitorCommand(instance_name, migrate_command)