Steps to reproduce this bug:
# cat test.sh
  #! /bin/bash -x
  virsh start domain
  sleep 5
  virsh qemu-monitor-command domain 'cpu_set 2 online' --hmp
# while true; do ./test.sh ; done

Then libvirtd will crash.

The reason is that:
we add a reference of obj when we open the monitor. We will reduce this
reference when we free the monitor.

If the reference of monitor is 0, we will free monitor automatically and
the reference of obj is reduced.

But in the function qemuDomainObjExitMonitorWithDriver(), we reduce this
reference again when the reference of monitor is 0.

It will cause the obj be freed in the function qemuDomainObjEndJob().

Then we start the domain again, and libvirtd will crash in the function
virDomainObjListSearchName(), because we pass a null pointer(obj->def->name)
to strcmp().
Signed-off-by: NWen Congyang <wency@cn.fujitsu.com>

This bug was reported by Shi Jin(jinzishuai@gmail.com):
=============
# virsh attach-disk RHEL6RC /var/lib/libvirt/images/test3.img vdb \
        --driver file --subdriver qcow2
Disk attached successfully

# virsh save RHEL6RC /var/lib/libvirt/images/memory.save
Domain RHEL6RC saved to /var/lib/libvirt/images/memory.save

# virsh restore /var/lib/libvirt/images/memory.save
error: Failed to restore domain from /var/lib/libvirt/images/memory.save
error: internal error unsupported driver name 'file'
       for disk '/var/lib/libvirt/images/test3.img'
=============

We check the driver name when we start or restore VM, but we do
not check it while attaching a disk. This adds the same check on disk
driverName used in qemuBuildCommandLine to qemudDomainAttachDevice.
Signed-off-by: NWen Congyang <wency@cn.fujitsu.com>

Steps to reproduce this bug:
# virsh qemu-monitor-command domain 'cpu_set 2 online' --hmp
The domain has 2 cpus, and we try to set the third cpu online.
The qemu crashes, and this command will hang.

The reason is that the refs is not 1 when we unwatch the monitor.
We lock the monitor, but we do not unlock it. So virCondWait()
will be blocked.
Signed-off-by: NWen Congyang <wency@cn.fujitsu.com>

* Correct the documentation for cgroup: the swap_hard_limit indicates
  mem+swap_hard_limit.
* Change cgroup private apis to: virCgroupGet/SetMemSwapHardLimit
Signed-off-by: NNikunj A. Dadhania <nikunj@linux.vnet.ibm.com>

* src/qemu/qemu_monitor.h (qemuMonitorMigrateToFd): New
prototype.
* src/qemu/qemu_monitor.c (qemuMonitorMigrateToFd): New function.

POSIX states about dd:

If the bs=expr operand is specified and no conversions other than
sync, noerror, or notrunc are requested, the data returned from each
input block shall be written as a separate output block; if the read
returns less than a full block and the sync conversion is not
specified, the resulting output block shall be the same size as the
input block. If the bs=expr operand is not specified, or a conversion
other than sync, noerror, or notrunc is requested, the input shall be
processed and collected into full-sized output blocks until the end of
the input is reached.

Since we aren't using conv=sync, there is no zero-padding, but our
use of bs= means that a short read results in a short write.  If
instead we use ibs= and obs=, then short reads are collected and dd
only has to do a single write, which can make dd more efficient.

* src/qemu/qemu_monitor.c (qemuMonitorMigrateToFile):
Avoid 'dd bs=', since it can cause short writes.

Fixes bug in commit acacced8

* src/qemu/qemu_command.c (qemuBuildCommandLine):
s/INVALID_ARG/CONFIG_UNSUPPORTED/.
Reported by Daniel P. Berrange.

* src/qemu/qemu_monitor_text.h (qemuMonitorTextMigrate): Declare
in place of individual monitor commands.
* src/qemu/qemu_monitor_json.h (qemuMonitorJSONMigrate): Likewise.
* src/qemu/qemu_monitor_text.c (qemuMonitorTextMigrateToHost)
(qemuMonitorTextMigrateToCommand, qemuMonitorTextMigrateToFile)
(qemuMonitorTextMigrateToUnix): Delete.
* src/qemu/qemu_monitor_json.c (qemuMonitorJSONMigrateToHost)
(qemuMonitorJSONMigrateToCommand, qemuMonitorJSONMigrateToFile)
(qemuMonitorJSONMigrateToUnix): Delete.
* src/qemu/qemu_monitor.c (qemuMonitorMigrateToHost)
(qemuMonitorMigrateToCommand, qemuMonitorMigrateToFile)
(qemuMonitorMigrateToUnix): Consolidate shared code.

Outgoing migration still uses a Unix socket and or exec netcat until
the next patch.

* src/qemu/qemu_migration.c (qemuMigrationPrepareTunnel):
Replace Unix socket with simpler pipe.
Suggested by Paolo Bonzini.

As perhaps other hypervisor drivers use different capacity units,
do the checking in qemu driver instead of in conf/domain_conf.c.

The newly added call to qemuAuditNetDevice in qemuPhysIfaceConnect was
assuming that res_ifname (the name of the macvtap device) was always
valid, but this isn't the case. If openMacvtapTap fails, it always
returns NULL, which would result in a segv.

Since the audit log only needs a record of devices that are actually
sent to qemu, and a failure to open the macvtap device means that no
device will be sent to qemu, we can solve this problem by only doing
the audit if openMacvtapTap is successful (in which case res_ifname is
guaranteed valid).

* src/qemu/qemu_command.c (qemuBuildCommandLine): Pass two
separate arguments, and fix indentation.

Implement domainSetBlkioParameters and domainGetBlkioParameters for QEmu
Signed-off-by: NGui Jianfeng <guijianfeng@cn.fujitsu.com>

Implements virDomainSetBlkioParameters and virDomainGetBlkioParameters and initialization
Signed-off-by: NGui Jianfeng <guijianfeng@cn.fujitsu.com>

This patch implements the code to address the new API
in the qemu driver.
Signed-off-by: NTaku Izumi <izumi.taku@jp.fujitsu.com>

This patch introduces a new libvirt API (virDomainSetMemoryFlags) and
a flag (virDomainMemoryModFlags).
Signed-off-by: NTaku Izumi <izumi.taku@jp.fujitsu.com>

Opening raw network devices with the intent of passing those fds to
qemu is worth an audit point.  This makes a multi-part audit: first,
we audit the device(s) that libvirt opens on behalf of the MAC address
of a to-be-created interface (which can independently succeed or
fail), then we audit whether qemu actually started the network device
with the same MAC (so searching backwards for successful audits with
the same MAC will show which fd(s) qemu is actually using).  Note that
it is possible for the fd to be successfully opened but no attempt
made to pass the fd to qemu (for example, because intermediate
nwfilter operations failed) - no interface start audit will occur in
that case; so the audit for a successful opened fd does not imply
rights given to qemu unless there is a followup audit about the
attempt to start a new interface.

Likewise, when a network device is hot-unplugged, there is only one
audit message about the MAC being discontinued; again, searching back
to the earlier device open audits will show which fds that qemu quits
using (and yes, I checked via /proc/<qemu-pid>/fd that qemu _does_
close out the fds associated with an interface on hot-unplug).  The
code would require much more refactoring to be able to definitively
state which device(s) were discontinued at that point, since we
currently don't record anywhere in the XML whether /dev/vhost-net was
opened for a given interface.

* src/qemu/qemu_audit.h (qemuAuditNetDevice): New prototype.
* src/qemu/qemu_audit.c (qemuAuditNetDevice): New function.
* src/qemu/qemu_command.h (qemuNetworkIfaceConnect)
(qemuPhysIfaceConnect, qemuOpenVhostNet): Adjust prototype.
* src/qemu/qemu_command.c (qemuNetworkIfaceConnect)
(qemuPhysIfaceConnect, qemuOpenVhostNet): Add audit points and
adjust parameters.
(qemuBuildCommandLine): Adjust caller.
* src/qemu/qemu_hotplug.c (qemuDomainAttachNetDevice): Likewise.

Since libvirt always passes /dev/net/tun to qemu via fd, we should
never trigger the cases where qemu tries to directly open the
device.  Therefore, it is safer to deny the cgroup device ACL.

* src/qemu/qemu_cgroup.c (defaultDeviceACL): Remove /dev/net/tun.
* src/qemu/qemu.conf (cgroup_device_acl): Reflect this change.

* src/qemu/qemu_hotplug.c (qemuDomainAttachNetDevice): Honor vhost
designations, similar to qemu_command code paths.
* src/qemu/qemu_command.h (qemuOpenVhostNet): New prototype.
* src/qemu/qemu_command.c (qemuOpenVhostNet): Export.

qemu driver in libvirt gained support for creating domain snapshots
almost a year ago in libvirt 0.8.0. Since then we enabled QMP support
for qemu >= 0.13.0 but QMP equivalents of {save,load,del}vm commands are
not implemented in current qemu (0.14.0) so the domain snapshot support
is not very useful.

This patch detects when the appropriate QMP command is not implemented
and tries to use human-monitor-command (aka HMP passthrough) to run
it's HMP equivalent.

To make it more obvious that it is only used for text monitor. The
naming also matches the style of qemuMonitorTextCommandWithFd.

So that it's obvious that they are supposed to be used with HMP commands.

JSON monitor command implementation can now just directly call text
monitor implementation and it will be automatically encapsulated into
QMP's human-monitor-command.

Some qemu monitor event handlers were issuing inadequate warning when
virDomainSaveStatus() failed. They copied the message from I/O error
handler without customizing it to provide better information on why
virDomainSaveStatus() was called.

* src/qemu/qemu_audit.h (qemuAuditCgroupMajor)
(qemuAuditCgroupPath): Add parameter.
* src/qemu/qemu_audit.c (qemuAuditCgroupMajor)
(qemuAuditCgroupPath): Add 'acl=rwm' to cgroup audit entries.
* src/qemu/qemu_cgroup.c: Update clients.
* src/qemu/qemu_driver.c (qemudDomainSaveFlag): Likewise.

Adding audit points showed that we were granting too much privilege
to qemu; it should not need any mknod rights to recreate any
devices.  On the other hand, lxc should have all device privileges.
The solution is adding a flag parameter.

This also lets us restrict write access to read-only disks.

* src/util/cgroup.h (virCgroup*Device*): Adjust prototypes.
* src/util/cgroup.c (virCgroupAllowDevice)
(virCgroupAllowDeviceMajor, virCgroupAllowDevicePath)
(virCgroupDenyDevice, virCgroupDenyDeviceMajor)
(virCgroupDenyDevicePath): Add parameter.
* src/qemu/qemu_driver.c (qemudDomainSaveFlag): Update clients.
* src/lxc/lxc_controller.c (lxcSetContainerResources): Likewise.
* src/qemu/qemu_cgroup.c: Likewise.
(qemuSetupDiskPathAllow): Also, honor read-only disks.

Also add ATTRIBUTE_NONNULL markers.

* src/qemu/qemu_audit.h: The pattern qemuDomainXXXAudit is
inconsistent; prefer qemuAuditXXX instead.
* src/qemu/qemu_audit.c: Reflect the renames.
* src/qemu/qemu_driver.c: Likewise.
* src/qemu/qemu_hotplug.c: Likewise.
* src/qemu/qemu_migration.c: Likewise.
* src/qemu/qemu_process.c: Likewise.

Although the cgroup device ACL controller path can be worked out
by researching the code, it is more efficient to include that
information directly in the audit message.

* src/util/cgroup.h (virCgroupPathOfController): New prototype.
* src/util/cgroup.c (virCgroupPathOfController): Export.
* src/libvirt_private.syms: Likewise.
* src/qemu/qemu_audit.c (qemuAuditCgroup): Use it.

Device names can be manipulated, so it is better to also log
the major/minor device number corresponding to the cgroup ACL
changes that libvirt made.  This required some refactoring
of the relatively new qemu cgroup audit code.

Also, qemuSetupChardevCgroup was only auditing on failure, not success.

* src/qemu/qemu_audit.h (qemuDomainCgroupAudit): Delete.
(qemuAuditCgroup, qemuAuditCgroupMajor, qemuAuditCgroupPath): New
prototypes.
* src/qemu/qemu_audit.c (qemuDomainCgroupAudit): Rename...
(qemuAuditCgroup): ...and drop a parameter.
(qemuAuditCgroupMajor, qemuAuditCgroupPath): New functions, to
allow listing device major/minor in audit.
(qemuAuditGetRdev): New helper function.
* src/qemu/qemu_driver.c (qemudDomainSaveFlag): Adjust callers.
* src/qemu/qemu_cgroup.c (qemuSetupDiskPathAllow)
(qemuSetupHostUsbDeviceCgroup, qemuSetupCgroup)
(qemuTeardownDiskPathDeny): Likewise.
(qemuSetupChardevCgroup): Likewise, fixing missing audit.

* src/qemu/qemu_audit.c (qemuDomainHostdevAudit): Avoid use of
"type", which has a pre-defined meaning.
(qemuDomainCgroupAudit): Likewise, as well as "item".

virRun gives pretty useful error output, let's not overwrite it unless there
is a good reason. Some places were providing more information about what
the commands were _attempting_ to do, however that's usually less useful from
a debugging POV than what actually happened.

* src/qemu/qemu_driver.c: qemuDomainUpdateDeviceFlags() is not disk
  specific as the message suggests

Signed-off-by: NWen Congyang <wency@cn.fujitsu.com>

The way to detach a USB disk is the same as that to detach a SCSI
disk. Rename this function and we can use it to detach a USB disk.
Signed-off-by: NWen Congyang <wency@cn.fujitsu.com>

Currently it sounds like spice is completely unsupported, which is
confusing.