This makes use of the QEMU guest agent to implement the
virDomainShutdownFlags and virDomainReboot APIs. With
no flags specified, it will prefer to use the agent, but
fallback to ACPI. Explicit choice can be made by using
a suitable flag

* src/qemu/qemu_driver.c: Wire up use of agent

There is now a standard QEMU guest agent that can be installed
and given a virtio serial channel

    <channel type='unix'>
      <source mode='bind' path='/var/lib/libvirt/qemu/f16x86_64.agent'/>
      <target type='virtio' name='org.qemu.guest_agent.0'/>
    </channel>

The protocol that runs over the guest agent is JSON based and
very similar to the JSON monitor. We can't use exactly the same
code because there are some odd differences in the way messages
and errors are structured. The qemu_agent.c file is based on
a combination and simplification of qemu_monitor.c and
qemu_monitor_json.c

* src/qemu/qemu_agent.c, src/qemu/qemu_agent.h: Support for
  talking to the agent for shutdown
* src/qemu/qemu_domain.c, src/qemu/qemu_domain.h: Add thread
  helpers for talking to the agent
* src/qemu/qemu_process.c: Connect to agent whenever starting
  a guest
* src/qemu/qemu_monitor_json.c: Make variable static

Fix inconsistent whitespace and long lines.

* src/qemu/qemu_capabilities.h (qemuCapsFlags): Improve formatting.

When converting a linear enum to a string, we have checks in
place in the VIR_ENUM_IMPL macro to ensure that there is one
string for every value, which lets us quickly flag if a user
added a value but forgot to add a counterpart string.  However,
this only works if we use the _LAST marker.

* cfg.mk (sc_require_enum_last_marker): New syntax check.
* src/conf/domain_conf.h (virDomainSnapshotState): Add new marker.
* src/conf/domain_conf.c (virDomainSnapshotState): Fix offender.
* src/qemu/qemu_monitor_json.c (qemuMonitorWatchdogAction)
(qemuMonitorIOErrorAction, qemuMonitorGraphicsAddressFamily):
Likewise.
* src/util/virtypedparam.c (virTypedParameter): Likewise.

Reusing common code makes things smaller; it also buys us some
additional safety, such as now rejecting duplicate parameters
during a set operation.

* src/qemu/qemu_driver.c (qemuDomainSetBlkioParameters)
(qemuDomainSetMemoryParameters, qemuDomainSetNumaParameters)
(qemuSetSchedulerParametersFlags)
(qemuDomainSetInterfaceParameters, qemuDomainSetBlockIoTune)
(qemuDomainGetBlkioParameters, qemuDomainGetMemoryParameters)
(qemuDomainGetNumaParameters, qemuGetSchedulerParametersFlags)
(qemuDomainBlockStatsFlags, qemuDomainGetInterfaceParameters)
(qemuDomainGetBlockIoTune): Use new helpers.
* src/esx/esx_driver.c (esxDomainSetSchedulerParametersFlags)
(esxDomainSetMemoryParameters)
(esxDomainGetSchedulerParametersFlags)
(esxDomainGetMemoryParameters): Likewise.
* src/libxl/libxl_driver.c
(libxlDomainSetSchedulerParametersFlags)
(libxlDomainGetSchedulerParametersFlags): Likewise.
* src/lxc/lxc_driver.c (lxcDomainSetMemoryParameters)
(lxcSetSchedulerParametersFlags, lxcDomainSetBlkioParameters)
(lxcDomainGetMemoryParameters, lxcGetSchedulerParametersFlags)
(lxcDomainGetBlkioParameters): Likewise.
* src/test/test_driver.c (testDomainSetSchedulerParamsFlags)
(testDomainGetSchedulerParamsFlags): Likewise.
* src/xen/xen_hypervisor.c (xenHypervisorSetSchedulerParameters)
(xenHypervisorGetSchedulerParameters): Likewise.

There was missing capability for blkiotune and thus specifying these
settings caused libvirt to run qemu with invalid parameters and then
reporting qemu error instead of the standard libvirt one. The support
for blkiotune setting was added in upstream qemu repo under commit
0563e191516289c9d2f282a8c50f2eecef2fa773.

It doesn't make sense to reattach a device to host while it's
still in use, e.g, by a domain.

pciTrySecondaryBusReset checks if there is active device on the
same bus, however, qemu driver doesn't maintain an effective
list for the inactive devices, and it passes meaningless argument
for parameter "inactiveDevs". e.g. (qemuPrepareHostdevPCIDevices)

if (!(pcidevs = qemuGetPciHostDeviceList(hostdevs, nhostdevs)))
    return -1;

..skipped...

if (pciResetDevice(dev, driver->activePciHostdevs, pcidevs) < 0)
    goto reattachdevs;

NB, the "pcidevs" used above are extracted from domain def, and
thus one won't be able to attach a device of which bus has other
device even detached from host (nodedev-detach). To see more
details of the problem:

RHBZ: https://bugzilla.redhat.com/show_bug.cgi?id=773667

This patch is to resolve the problem by introducing an inactive
PCI device list (just like qemu_driver->activePciHostdevs), and
the whole logic is:

  * Add the device to inactive list during nodedev-dettach
  * Remove the device from inactive list during nodedev-reattach
  * Remove the device from inactive list during attach-device
    (for non-managed device)
  * Add the device to inactive list after detach-device, only
    if the device is not managed

With the above, we have a sufficient inactive PCI device list, and thus
we can use it for pciResetDevice. e.g.(qemuPrepareHostdevPCIDevices)

if (pciResetDevice(dev, driver->activePciHostdevs,
                   driver->inactivePciHostdevs) < 0)
    goto reattachdevs;

This introduces new attribute wrpolicy with only supported
value as immediate. This will be an optional
attribute with no defaults. This helps specify whether
to skip the host page cache.

When wrpolicy is specified, meaning when wrpolicy=immediate
a writeback is explicitly initiated for the dirty pages in
the host page cache as part of the guest file write operation.

Usage:
<filesystem type='mount' accessmode='passthrough'>
  <driver type='path' wrpolicy='immediate'/>
  <source dir='/export/to/guest'/>
  <target dir='mount_tag'/>
</filesystem>

Currently this only works with type='mount' for the QEMU/KVM driver.
Signed-off-by: NDeepak C Shetty <deepakcs@linux.vnet.ibm.com>

In the past we didn't reserve 0:0:2.0 PCI address if there was no video
device assigned to a domain, which made it impossible to add a video
device later on. So we fixed it (commit v0.9.0-37-g7b2cac12) by always
reserving that address. However, that breaks existing domains without
video devices that already have another device assigned to the
problematic address.

This patch reserves address 0:0:2.0 only in case it was not explicitly
assigned to another device, which means libvirt will try to keep this
address free and will not automatically assign it new devices. But
existing domains for which older libvirt already assigned the address to
a non-video device will keep working as they used to work before 0.9.1.
Moreover, users who want to create a domain without a video device and
use its address for another device may do so by explicitly configuring
the PCI address in domain XML.

This adds support for host-model and host-passthrough CPU modes to qemu
driver. The host-passthrough mode is mapped to -cpu host.

There are several reasons for doing this:

- the CPU specification is out of libvirt's control so we cannot
  guarantee stable guest ABI
- not every feature of a CPU may actually work as expected when
  advertised directly to a guest
- migration between two machines with exactly the same CPU may work but
  no guarantees can be made
- this mode is not supported and its use is at one's own risk

VIR_DOMAIN_XML_UPDATE_CPU flag for virDomainGetXMLDesc may be used to
get updated custom mode guest CPU definition in case it depends on host
CPU. This patch implements the same behavior for host-model and
host-passthrough CPU modes.

In case a hypervisor doesn't support the exact CPU model requested by a
domain XML, we automatically fallback to a closest CPU model the
hypervisor supports (and make sure we add/remove any additional features
if needed). This patch adds 'fallback' attribute to model element, which
can be used to disable this automatic fallback.

Commit 5d784bd6 was a nice attempt to
clarify the semantics by requiring domain name from dxml to either match
original name or dname. However, setting dxml domain name to dname
doesn't really work since destination host needs to know the original
domain name to be able to use it in migration cookies. This patch
requires domain name in dxml to match the original domain name. The
change should be safe and backward compatible since migration would fail
just a bit later in the process.

We can't call qemuCapsExtractVersionInfo() from test code, because it
expects to be able to call the emulator, and for testing we have fake
emulators that can't be executed. For that reason qemuxml2argvtest.c
doesn't call qemuDomainAssignPCIAddresses(), instead it open codes its
own version.

That means we can't call qemuDomainAssignAddresses() from the test code,
instead we need to manually call qemuDomainAssignSpaprVioAddresses().

Also add logic to cope with qemuDomainAssignSpaprVioAddresses() failing,
so that we can write a test that checks for a known failure in there.
Signed-off-by: NMichael Ellerman <michael@ellerman.id.au>

Adding a new model for virtio-scsi roughly follows the same scheme
as the previous patch.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

KVM will be able to use a PCI SCSI controller even on POWER.  Let
the user specify the vSCSI controller by other means than a default.

After this patch, the QEMU driver will actually look at the model
and reject anything but auto, lsilogic and ibmvscsi.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

The new introduced optional attribute "copy_on_read</code> controls
whether to copy read backing file into the image file. The value can
be either "on" or "off". Copy-on-read avoids accessing the same backing
file sectors repeatedly and is useful when the backing file is over a
slow network. By default copy-on-read is off.

QEMU does not support security_model for anything but 'path' fs driver type.
Currently in libvirt, when security_model ( accessmode attribute) is not
specified it auto-generates it irrespective of the fs driver type, which
can result in a qemu error for drivers other than path. This patch ensures
that the qemu cmdline is correctly generated by taking into account the
fs driver type.
Signed-off-by: NDeepak C Shetty <deepakcs@linux.vnet.ibm.com>

When sVirt is integrated with the LXC driver, it will be neccessary
to invoke the security driver APIs using only a virDomainDefPtr
since the lxc_container.c code has no virDomainObjPtr available.
Aside from two functions which want obj->pid, every bit of the
security driver code only touches obj->def. So we don't need to
pass a virDomainObjPtr into the security drivers, a virDomainDefPtr
is sufficient. Two functions also gain a 'pid_t pid' argument.

* src/qemu/qemu_driver.c, src/qemu/qemu_hotplug.c,
  src/qemu/qemu_migration.c, src/qemu/qemu_process.c,
  src/security/security_apparmor.c,
  src/security/security_dac.c,
  src/security/security_driver.h,
  src/security/security_manager.c,
  src/security/security_manager.h,
  src/security/security_nop.c,
  src/security/security_selinux.c,
  src/security/security_stack.c: Change all security APIs to use a
  virDomainDefPtr instead of virDomainObjPtr

When disk snapshots were first implemented, libvirt blindly refused
to allow an external snapshot destination that already exists, since
qemu will blindly overwrite the contents of that file during the
snapshot_blkdev monitor command, and we don't like a default of
data loss by default.  But VDSM has a scenario where NFS permissions
are intentionally set so that the destination file can only be
created by the management machine, and not the machine where the
guest is running, so that libvirt will necessarily see the destination
file already existing; adding a flag will allow VDSM to force the file
reuse without libvirt complaining of possible data loss.

https://bugzilla.redhat.com/show_bug.cgi?id=767104

* include/libvirt/libvirt.h.in (virDomainSnapshotCreateFlags): Add
VIR_DOMAIN_SNAPSHOT_CREATE_REUSE_EXT.
* src/libvirt.c (virDomainSnapshotCreateXML): Document it.  Add
note about partial failure.
* tools/virsh.c (cmdSnapshotCreate, cmdSnapshotCreateAs): Add new
flag.
* tools/virsh.pod (snapshot-create, snapshot-create-as): Document
it.
* src/qemu/qemu_driver.c (qemuDomainSnapshotDiskPrepare)
(qemuDomainSnapshotCreateXML): Implement the new flag.

This *kind of* addresses:

  https://bugzilla.redhat.com/show_bug.cgi?id=772395

(it doesn't eliminate the failure to start, but causes libvirt to give
a better idea about the cause of the failure).

If a guest uses a kvm emulator (e.g. /usr/bin/qemu-kvm) and the guest
is started when kvm isn't available (either because virtualization is
unavailable / has been disabled in the BIOS, or the kvm modules
haven't been loaded for some reason), a semi-cryptic error message is
logged:

  libvirtError: internal error Child process (LC_ALL=C
  PATH=/sbin:/usr/sbin:/bin:/usr/bin /usr/bin/qemu-kvm -device ? -device
  pci-assign,? -device virtio-blk-pci,? -device virtio-net-pci,?) status
  unexpected: exit status 1

This patch notices at process start that a guest needs kvm, and checks
for the presence of /dev/kvm (a reasonable indicator that kvm is
available) before trying to execute the qemu binary. If kvm isn't
available, a more useful (too verbose??) error is logged.

It should be a copy-paste error, the result is programming will result in an
infinite loop again due to without iterating 'j' variable.

* src/qemu/qemu_driver.c: fix a typo on qemuDomainSetBlkioParameters.

RHBZ: https://bugzilla.redhat.com/show_bug.cgi?id=770520Signed-off-by: NAlex Jia <ajia@redhat.com>

In the past, generic SCSI commands issued from a guest to a virtio
disk were always passed through to the underlying disk by qemu, and
the kernel would also pass them on.

As a result of CVE-2011-4127 (see:
http://seclists.org/oss-sec/2011/q4/536), qemu now honors its
scsi=on|off device option for virtio-blk-pci (which enables/disables
passthrough of generic SCSI commands), and the kernel will only allow
the commands for physical devices (not for partitions or logical
volumes). The default behavior of qemu is still to allow sending
generic SCSI commands to physical disks that are presented to a guest
as virtio-blk-pci devices, but libvirt prefers to disable those
commands in the standard virtio block devices, enabling it only when
specifically requested (hopefully indicating that the requester
understands what they're asking for). For this purpose, a new libvirt
disk device type (device='lun') has been created.

device='lun' is identical to the default device='disk', except that:

1) It is only allowed if bus='virtio', type='block', and the qemu
   version is "new enough" to support it ("new enough" == qemu 0.11 or
   better), otherwise the domain will fail to start and a
   CONFIG_UNSUPPORTED error will be logged).

2) The option "scsi=on" will be added to the -device arg to allow
   SG_IO commands (if device !='lun', "scsi=off" will be added to the
   -device arg so that SG_IO commands are specifically forbidden).

Guests which continue to use disk device='disk' (the default) will no
longer be able to use SG_IO commands on the disk; those that have
their disk device changed to device='lun' will still be able to use SG_IO
commands.

*docs/formatdomain.html.in - document the new device attribute value.
*docs/schemas/domaincommon.rng - allow it in the RNG
*tests/* - update the args of several existing tests to add scsi=off, and
 add one new test that will test scsi=on.
*src/conf/domain_conf.c - update domain XML parser and formatter

*src/qemu/qemu_(command|driver|hotplug).c - treat
 VIR_DOMAIN_DISK_DEVICE_LUN *almost* identically to
 VIR_DOMAIN_DISK_DEVICE_DISK, except as indicated above.

Note that no support for this new device value was added to any
hypervisor drivers other than qemu, because it's unclear what it might
mean (if anything) to those drivers.

This patch adds two capabilities flags to deal with various aspects
of supporting SG_IO commands on virtio-blk-pci devices:

  QEMU_CAPS_VIRTIO_BLK_SCSI
    set if -device virtio-blk-pci accepts the scsi="on|off" option
    When present, this is on by default, but can be set to off to disable
    SG_IO functions.

  QEMU_CAPS_VIRTIO_BLK_SG_IO
    set if SG_IO commands are supported in the virtio-blk-pci driver
    (present since qemu 0.11 according to a qemu developer, if I
     understood correctly)

This fixes https://bugzilla.redhat.com/show_bug.cgi?id=638633

Although scripts are not used by interfaces of type other than
"ethernet" in qemu, due to the fact that the parser stores the script
name in a union that is only valid when type is ethernet or bridge,
there is no way for anyone except the parser itself to catch the
problem of specifying an interface script for an inappropriate
interface type (by the time the parsed data gets back to the code that
called the parser, all evidence that a script was specified is
forgotten).

Since the parser itself should be agnostic to which type of interface
allows scripts (an example of why: a script specified for an interface
of type bridge is valid for xen domains, but not for qemu domains),
the solution here is to move the script out of the union(s) in the
DomainNetDef, always populate it when specified (regardless of
interface type), and let the driver decide whether or not it is
appropriate.

Currently the qemu, xen, libxml, and uml drivers recognize the script
parameter and do something with it (the uml driver only to report that
it isn't supported). Those drivers have been updated to log a
CONFIG_UNSUPPORTED error when a script is specified for an interface
type that's inappropriate for that particular hypervisor.

(NB: There was earlier discussion of solving this problem by adding a
VALIDATE flag to all libvirt APIs that accept XML, which would cause
the XML to be validated against the RNG files. One statement during
that discussion was that the RNG shouldn't contain hypervisor-specific
things, though, and a proper solution to this problem would require
that (again, because a script for an interface of type "bridge" is
accepted by xen, but not by qemu).

Commit ae523427 missed one pair of functions that could use
the helper routine.

* src/qemu/qemu_driver.c (qemuSetSchedulerParametersFlags)
(qemuGetSchedulerParametersFlags): Simplify.

Detected by valgrind. Leak introduced in commit 5745dc12.

* src/qemu/qemu_command.c: fix memory leak on failure and successful path.

* How to reproduce?
% valgrind -v --leak-check=full ./qemuargv2xmltest

* Actual result:

==2196== 80 bytes in 1 blocks are definitely lost in loss record 3 of 4
==2196==    at 0x4A05FDE: malloc (vg_replace_malloc.c:236)
==2196==    by 0x39CF07F6E1: strdup (in /lib64/libc-2.12.so)
==2196==    by 0x419823: qemuParseRBDString (qemu_command.c:1657)
==2196==    by 0x4221ED: qemuParseCommandLine (qemu_command.c:5934)
==2196==    by 0x422AFB: qemuParseCommandLineString (qemu_command.c:7561)
==2196==    by 0x416864: testCompareXMLToArgvHelper (qemuargv2xmltest.c:48)
==2196==    by 0x417DB1: virtTestRun (testutils.c:141)
==2196==    by 0x415CAF: mymain (qemuargv2xmltest.c:175)
==2196==    by 0x4174A7: virtTestMain (testutils.c:696)
==2196==    by 0x39CF01ECDC: (below main) (in /lib64/libc-2.12.so)
==2196==
==2196== LEAK SUMMARY:
==2196==    definitely lost: 80 bytes in 1 blocks
Signed-off-by: NAlex Jia <ajia@redhat.com>

When setting numa nodeset for a domain which has no nodeset set
before, libvirtd crashes by dereferencing the pointer to the old
nodemask which is null in that case.

Commit baade4d fixed a memory leak on failure, but in the process,
introduced a use-after-free on success, which can be triggered with:

1. set bandwidth with --live
2. query bandwidth
3. set bandwidth with --live

* src/qemu/qemu_driver.c (qemuDomainSetInterfaceParameters): Don't
free newBandwidth on success.
Reported by Hu Tao.

https://bugzilla.redhat.com/show_bug.cgi?id=770954

Typo has existed since API introduction in commit ee0d8c3b.

* src/qemu/qemu_driver.c (qemuDomainBlockStatsFlags): Use correct
name.

Most severe here is a latent (but currently untriggered) memory leak
if any hypervisor ever adds a string interface property; the
remainder are mainly cosmetic.

* include/libvirt/libvirt.h.in (VIR_DOMAIN_BANDWIDTH_*): Move
macros closer to interface that uses them, and document type.
* src/libvirt.c (virDomainSetInterfaceParameters)
(virDomainGetInterfaceParameters): Formatting tweaks.
* daemon/remote.c (remoteDispatchDomainGetInterfaceParameters):
Avoid memory leak.
* src/libvirt_public.syms (LIBVIRT_0.9.9): Sort lines.
* src/libvirt_private.syms (domain_conf.h): Likewise.
* src/qemu/qemu_driver.c (qemuDomainSetInterfaceParameters): Fix
comments, break long lines.

Detected by Coverity. Leaks introduced in commit e8d6b293.
Signed-off-by: NAlex Jia <ajia@redhat.com>

Leak detected by Coverity, and introduced in commit 93ab5859.
Reported by Alex Jia.

* src/qemu/qemu_driver.c (qemuDomainSetBlkioParameters): Free
devices array on error.

* src/qemu/qemu_driver.c: implement the qemu driver support

https://bugzilla.redhat.com/show_bug.cgi?id=770520

We had two nested loops both trying to use 'i' as the iteration
variable, which can result in an infinite loop when the inner
loop interferes with the outer loop.  Introduced in commit 93ab5859.

* src/qemu/qemu_driver.c (qemuDomainSetBlkioParameters): Don't
reuse iteration variable across two loops.

In order to avoid situation where a USB device is
in use by two domains, we must keep a list of already
attached devices like we do for PCI.

This patch adds max_files option to qemu.conf which can be used to
override system default limit on number of opened files that are
allowed for qemu user.