Commit 89c10241 authored by Dimitris Aragiorgis's avatar Dimitris Aragiorgis Committed by Thomas Thrainer
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hotplug: Call each qemu commmand with an own socat

Previously we issued one socat command with two "\n" separated
actions (e.g. netdev_add ...\ndevice_add...)

After having observed a strange monitor behavior [1] splitting
those commands and introducing a sleep time in between, may reduce
any race possibilities. Additionally it will be a step forward
parsing monitor output of each command and decide whether to
modify runtime files or raise a HotplugError.

This patch simply changes _CallHotplugCommand() to take a
list of commands and issue them separately. Introduces one second
sleep after each command and removes sleep from HotModDevice().


Signed-off-by: default avatarDimitris Aragiorgis <>
Signed-off-by: default avatarThomas Thrainer <>
Reviewed-by: default avatarThomas Thrainer <>
parent 401b773e
......@@ -2069,11 +2069,13 @@ class KVMHypervisor(hv_base.BaseHypervisor):
if (int(v_major), int(v_min)) < (1, 0):
raise errors.HotplugError("Hotplug not supported for qemu versions < 1.0")
def _CallHotplugCommand(self, name, cmd):
output = self._CallMonitorCommand(name, cmd)
# TODO: parse output and check if succeeded
for line in output.stdout.splitlines():"%s", line)
def _CallHotplugCommands(self, name, cmds):
for c in cmds:
output = self._CallMonitorCommand(name, c)
# TODO: parse output and check if succeeded
for line in output.stdout.splitlines():"%s", line)
def HotAddDevice(self, instance, dev_type, device, extra, seq):
""" Helper method to hot-add a new device
......@@ -2088,21 +2090,21 @@ class KVMHypervisor(hv_base.BaseHypervisor):
kvm_devid = _GenerateDeviceKVMId(dev_type, device)
runtime = self._LoadKVMRuntime(instance)
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
cmds += ["device_add %s" % args]
utils.WriteFile(self._InstanceNICFile(, seq), data=tap)
self._CallHotplugCommand(, command)
self._CallHotplugCommands(, cmds)
# update relevant entries in runtime file
index = _DEVICE_RUNTIME_INDEX[dev_type]
entry = _RUNTIME_ENTRY[dev_type](device, extra)
......@@ -2121,13 +2123,13 @@ class KVMHypervisor(hv_base.BaseHypervisor):
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\n" % kvm_devid
command += "drive_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
cmds = ["device_del %s" % kvm_devid]
cmds += ["netdev_del %s" % kvm_devid]
utils.RemoveFile(self._InstanceNICFile(, seq))
self._CallHotplugCommand(, command)
self._CallHotplugCommands(, cmds)
index = _DEVICE_RUNTIME_INDEX[dev_type]
self._SaveKVMRuntime(instance, runtime)
......@@ -2144,8 +2146,6 @@ class KVMHypervisor(hv_base.BaseHypervisor):
if dev_type == constants.HOTPLUG_TARGET_NIC:
# putting it back in the same pci slot
device.pci = self.HotDelDevice(instance, dev_type, device, _, seq)
# TODO: remove sleep when socat gets removed
self.HotAddDevice(instance, dev_type, device, _, seq)
def _PassTapFd(self, instance, fd, nic):
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