Remove unused 'cgroup' variable in qemuDomainAttachDeviceDiskLive() to
resolve coverity DEADCODE complaint

When using a <interface type="network"> that points to a network with
hostdev forwarding mode a hostdev alias is created for the network. This
allias is inserted into the hostdev list, but is backed with a part of
the network object that it is connected to.

When a VM is being stopped qemuProcessStop() calls
networkReleaseActualDevice() which eventually frees the memory for the
hostdev object. Afterwards when the domain definition is being freed by
virDomainDefFree() an invalid pointer is accessed by
virDomainHostdevDefFree() and may cause a crash of the daemon.

This patch removes the entry in the hostdev list before freeing the
depending memory to avoid this issue.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1000973

If there's no hard_limit set and domain uses VFIO we still must lock
the guest memory (prerequisite from qemu). Hence, we should compute
the amount to be locked from max_balloon.

We don't want tests to wait 5 seconds for an event which we know will
never come.

If user requested multiqueue networking, beside multiple /dev/tap and
/dev/vhost-net openings, we forgot to pass mq=on onto the -device
virtio-net-pci command line. This is advised at:

  http://www.linux-kvm.org/page/Multiqueue#Enable_MQ_feature

This function is to guess the correct limit for maximal memory
usage by qemu for given domain. This can never be guessed
correctly, not to mention all the pains and sleepless nights this
code has caused. Once somebody discovers algorithm to solve the
Halting Problem, we can compute the limit algorithmically. But
till then, this code should never see the light of the release
again.

qemuDomainAttachVirtioDiskDevice passes NULL as domainDef which is later
referenced in qemuDomainAttachVirtioDiskDevice:

 Program terminated with signal 11, Segmentation fault.
 #0  qemuBuildDeviceAddressStr (buf=buf@entry=0xb646de78, info=info@entry=0xb0a02360, qemuCaps=qemuCaps@entry=0xb8fdfdc8,
     domainDef=<error reading variable: Unhandled dwarf expression opcode 0xfa>,
     domainDef=<error reading variable: Unhandled dwarf expression opcode 0xfa>) at qemu/qemu_command.c:2869
 2869            for (i = 0; i < domainDef->ncontrollers; i++) {
 (gdb) bt
 #0  qemuBuildDeviceAddressStr (buf=buf@entry=0xb646de78, info=info@entry=0xb0a02360, qemuCaps=qemuCaps@entry=0xb8fdfdc8,
     domainDef=<error reading variable: Unhandled dwarf expression opcode 0xfa>,
     domainDef=<error reading variable: Unhandled dwarf expression opcode 0xfa>) at qemu/qemu_command.c:2869
 #1  0xb18ad6f8 in qemuBuildDriveDevStr (def=def@entry=0x0, disk=disk@entry=0xb0a02288, bootindex=bootindex@entry=0, qemuCaps=0xb8fdfdc8)
     at qemu/qemu_command.c:4316
 #2  0xb18d097f in qemuDomainAttachVirtioDiskDevice (conn=conn@entry=0xb90129a8, driver=driver@entry=0xb8fe29b8, vm=vm@entry=0xb8fe0c40,
     disk=disk@entry=0xb0a02288) at qemu/qemu_hotplug.c:278
 #3  0xb193f7ba in qemuDomainAttachDeviceDiskLive (dev=0xb0a35308, vm=0xb8fe0c40, driver=0xb8fe29b8, conn=0xb90129a8) at qemu/qemu_driver.c:6356
 #4  qemuDomainAttachDeviceLive (dev=0xb0a35308, vm=0xb8fe0c40, dom=<optimized out>) at qemu/qemu_driver.c:6418
 #5  qemuDomainAttachDeviceFlags (dom=dom@entry=0xb0a020b8,
     xml=xml@entry=0xb90953f0 "<disk type='file' device='disk'>\n  <source file='/var/lib/jenkins/jobs/libvirt-tck-build/workspace/scratchdir/200-disk-hotplug/extra.img'/>\n  <target dev='vdb' bus='virtio'/>\n</disk>\n", flags=3103664568, flags@entry=1) at qemu/qemu_driver.c:7079
 #6  0xb193f9cb in qemuDomainAttachDevice (dom=0xb0a020b8,
     xml=0xb90953f0 "<disk type='file' device='disk'>\n  <source file='/var/lib/jenkins/jobs/libvirt-tck-build/workspace/scratchdir/200-disk-hotplug/extra.img'/>\n  <target dev='vdb' bus='virtio'/>\n</disk>\n") at qemu/qemu_driver.c:7120
 #7  0xb7244827 in virDomainAttachDevice (domain=domain@entry=0xb0a020b8,
     xml=0xb90953f0 "<disk type='file' device='disk'>\n  <source file='/var/lib/jenkins/jobs/libvirt-tck-build/workspace/scratchdir/200-disk-hotplug/extra.img'/>\n  <target dev='vdb' bus='virtio'/>\n</disk>\n") at libvirt.c:10912
 #8  0xb7765ddb in remoteDispatchDomainAttachDevice (args=0xb9094ef0, rerr=0xb646e1f0, client=<optimized out>, server=<optimized out>,
     msg=<optimized out>) at remote_dispatch.h:2296
 #9  remoteDispatchDomainAttachDeviceHelper (server=0xb8fba0e8, client=0xb0a00730, msg=0xb0a350b8, rerr=0xb646e1f0, args=0xb9094ef0, ret=0xb9094dc8)
     at remote_dispatch.h:2274
 #10 0xb72b1013 in virNetServerProgramDispatchCall (msg=0xb0a350b8, client=0xb0a00730, server=0xb8fba0e8, prog=0xb8fc21c8)
     at rpc/virnetserverprogram.c:435
 #11 virNetServerProgramDispatch (prog=0xb8fc21c8, server=server@entry=0xb8fba0e8, client=0xb0a00730, msg=0xb0a350b8) at rpc/virnetserverprogram.c:305
 #12 0xb72aa167 in virNetServerProcessMsg (msg=<optimized out>, prog=<optimized out>, client=<optimized out>, srv=0xb8fba0e8)
     at rpc/virnetserver.c:165
 #13 virNetServerHandleJob (jobOpaque=0xb0a0a850, opaque=0xb8fba0e8) at rpc/virnetserver.c:186
 #14 0xb7189108 in virThreadPoolWorker (opaque=opaque@entry=0xb8fa3250) at util/virthreadpool.c:144
 #15 0xb71885e5 in virThreadHelper (data=0xb8fa32a8) at util/virthreadpthread.c:161
 #16 0xb70d6954 in start_thread (arg=0xb646eb70) at pthread_create.c:304
 #17 0xb704e95e in clone () at ../sysdeps/unix/sysv/linux/i386/clone.S:130

This was found by libvirtt-tck:

     http://honk.sigxcpu.org:8001/job/libvirt-tck-debian-wheezy-qemu-session/1311/console

Hotplugging a single SCSI device works, but adding additional ones
result in an error from QEMU:

[root@gpok197 ~]# virsh attach-device guest01 blah.xml
Device attached successfully
[root@gpok197 ~]# virsh attach-device guest01 blah2.xml
error: Failed to attach device from blah2.xml
error: internal error unable to execute QEMU command 'device_add': Duplicate ID 'hostdev0' for device

The hostdev ID that is created is always set to zero, regardless
of the contents of the XML.  Changing the index in the hotplug case
to a negative one so the next available index is used.
Signed-off-by: NEric Farman <farman@linux.vnet.ibm.com>
Reviewed-by: NViktor Mihajlovski <mihajlov@linux.vnet.ibm.com>

We had been setting the device alias in the devinceinfo for pci
controllers to "pci%u", but then hardcoding "pci.%u" when creating the
device address for other devices using that pci bus. This all worked
just fine until we encountered the built-in "pcie.0" bus (the PCIe
root complex) in Q35 machines.

In order to create the correct commandline for this one case, this
patch:

1) sets the alias for PCI controllers correctly, to "pci.%u" (or
"pcie.%u" for the pcie-root controller)

2) eliminates the hardcoded "pci.%u" for pci controllers when
generatuing device address strings, and instead uses the controller's
alias.

3) plumbs a pointer to the virDomainDef all the way down to
qemuBuildDeviceAddressStr. This was necessary in order to make the
aliase of the controller *used by a device* available (previously
qemuBuildDeviceAddressStr only had the deviceinfo of the device
itself, *not* of the controller it was connecting to). This made for a
larger than desired diff, but at least in the future we won't have to
do it again, since all the information we could possibly ever need for
future enhancements is in the virDomainDef. (right?)

This should be done for *all* controllers, but for now we just do it
in the case of PCI controllers, to reduce the likelyhood of
regression.

Moreover, since virAsprintf now does report OOM error, there's no need
to call virReportOOMError in error path.

Introduced in commit 24b08219; compilation on RHEL 6.4 complained:
qemu/qemu_hotplug.c: In function 'qemuDomainAttachChrDevice':
qemu/qemu_hotplug.c:1257: error: declaration of 'remove' shadows a global declaration [-Wshadow]
/usr/include/stdio.h:177: error: shadowed declaration is here [-Wshadow]

* src/qemu/qemu_hotplug.c (qemuDomainAttachChrDevice): Avoid the
name 'remove'.
Signed-off-by: NEric Blake <eblake@redhat.com>

Since previous patches has prepared everything for us, we may now
implement live hotplug of a character device.

There are two levels on which a device may be hotplugged: config
and live. The config level requires just an insert or remove from
internal domain definition structure, which is exactly what this
patch does. There is currently no implementation for a chardev
update action, as there's not much to be updated. But more
importantly, the only thing that can be updated is path or socket
address by which chardevs are distinguished. So the update action
is currently not supported.

If an error occurs during qemuDomainAttachNetDevice after the macvtap
was created in qemuPhysIfaceConnect, the macvtap device gets left behind.
This patch adds code to the cleanup routine to delete the macvtap.
Signed-off-by: NMatthew Rosato <mjrosato@linux.vnet.ibm.com>
Reviewed-by: NViktor Mihajlovski <mihajlov@linux.vnet.ibm.com>

I recently patches the callers to virPCIDeviceReset() to not call it
if the current driver for a device was vfio-pci (since that driver
will always reset the device itself when appropriate. At the time, Dan
Berrange suggested that I could instead modify virPCIDeviceReset
to check the currently bound driver for the device, and decide
for itself whether or not to go ahead with the reset.

This patch removes the previously added checks, and replaces them with
a check down in virPCIDeviceReset(), as suggested.

The functional difference here is that previously we were deciding
based on either the hostdev configuration or the value of
stubDriverName in the virPCIDevice object, but now we are actually
comparing to the "driver" link in the device's sysfs entry
directly. In practice, both should be the same.

Convert the type of loop iterators named 'i', 'j', k',
'ii', 'jj', 'kk', to be 'size_t' instead of 'int' or
'unsigned int', also santizing 'ii', 'jj', 'kk' to use
the normal 'i', 'j', 'k' naming
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

I just learned that VFIO resets PCI devices when they are assigned to
guests / returned to the host, so it is redundant for libvirt to reset
the devices. This patch inhibits calling virPCIDeviceReset to devices
that will be/were assigned using VFIO.

Commit 752596b5 broke the build with -Werror

qemu/qemu_hotplug.c: In function 'qemuDomainChangeGraphics':
qemu/qemu_hotplug.c:1980:39: error: declaration of 'listen' shadows a
  global declaration [-Werror=shadow]

Fix with s/listen/newlisten/

Currently, we have a bug when updating a graphics device. A graphics device can
have a listen address set. This address is either defined by user (in which case
it's type is VIR_DOMAIN_GRAPHICS_LISTEN_TYPE_ADDRESS) or it can be inherited
from a network (in which case it's type is
VIR_DOMAIN_GRAPHICS_LISTEN_TYPE_NETWORK). However, in both cases we have a
listen address to process (e.g. during migration, as I've tried to fix in
7f15ebc7).
Later, when a user tries to update the graphics device (e.g. set a password),
we check if listen addresses match the original as qemu doesn't know how to
change listen address yet. Hence, users are required to not change the listen
address. The implementation then just dumps listen addresses and compare them.
Previously, while dumping the listen addresses, NULL was returned for NETWORK.
After my patch, this is no longer true, and we get a listen address for olddev
even if it is a type of NETWORK. So we have a real string on one side, the NULL
from user's XML on the other side and hence we think user wants to change the
listen address and we refuse it.

Therefore, we must take the type of listen address into account as well.

If we are just ejecting media, ret == -1 even after the retry loop
determines that the tray is open, as requested. This means media
disconnect always report's error.

Fix it, and fix some other mini issues:

- Don't overwrite the 'eject' error message if the retry loop fails
- Move the retries decrement inside the loop, otherwise the final loop
  might succeed, yet retries == 0 and we will raise error
- Setting ret = -1 in the disk->src check is unneeded
- Fix comment typos

cc: mprivozn@redhat.com

In order to learn libvirt multiqueue several things must be done:

1) The '/dev/net/tun' device needs to be opened multiple times with
IFF_MULTI_QUEUE flag passed to ioctl(fd, TUNSETIFF, &ifr);

2) Similarly, '/dev/vhost-net' must be opened as many times as in 1)
in order to keep 1:1 ratio recommended by qemu and kernel folks.

3) The command line construction code needs to switch from 'fd=X' to
'fds=X:Y:...:Z' and from 'vhostfd=X' to 'vhostfds=X:Y:...:Z'.

4) The monitor handling code needs to learn to pass multiple FDs.

In 84c59ffa I've tried to fix changing ejectable media process. The
process should go like this:

1) we need to call 'eject' on the monitor
2) we should wait for 'DEVICE_TRAY_MOVED' event
3) now we can issue 'change' command

However, while waiting in step 2) the domain monitor was locked. So
even if qemu reported the desired event, the proper callback was not
called immediately. The monitor handling code needs to lock the
monitor in order to read the event. So that's the first lock we must
not hold while waiting. The second one is the domain lock. When
monitor handling code reads an event, the appropriate callback is
called then. The first thing that each callback does is locking the
corresponding domain as a domain or its device is about to change
state. So we need to unlock both monitor and VM lock. Well, holding
any lock while sleep()-ing is not the best thing to do anyway.

Since 0d70656a, it starts to access the sysfs files to build
the qemu command line (by virSCSIDeviceGetSgName, which is to find
out the scsi generic device name by adpater:bus:target:unit), there
is no way to work around, qemu wants to see the scsi generic device
like "/dev/sg6" anyway.

And there might be other places which need to access sysfs files
when building qemu command line in future.

Instead of increasing the arguments of qemuBuildCommandLine, this
introduces a new callback for qemuBuildCommandLine, and thus tests
can register their own callbacks for sysfs test input files accessing.

* src/qemu/qemu_command.h: (New callback struct
                            qemuBuildCommandLineCallbacks;
                            extern buildCommandLineCallbacks)
* src/qemu/qemu_command.c: (wire up the callback struct)
* src/qemu/qemu_driver.c: (Use the new syntax of qemuBuildCommandLine)
* src/qemu/qemu_hotplug.c: Likewise
* src/qemu/qemu_process.c: Likewise
* tests/testutilsqemu.[ch]: (Helper testSCSIDeviceGetSgName;
                             callback struct testCallbacks;)
* tests/qemuxml2argvtest.c: (Use testCallbacks)
* src/tests/qemuxmlnstest.c: (Like above)

This adds both attachment and detachment support for scsi host
device.
Signed-off-by: NHan Cheng <hanc.fnst@cn.fujitsu.com>
Signed-off-by: NOsier Yang <jyang@redhat>