Make use of the existing <filesystem> element to support plan9fs
filesystem passthrough in the QEMU driver

    <filesystem type='mount'>
      <source dir='/export/to/guest'/>
      <target dir='/import/from/host'/>
    </filesystem>

NB, the target is not actually a directory, it is merely a arbitrary
string tag that is exported to the guest as a hint for where to mount
it.

QEmu startup will pick up the memory tunables specified in the domain
configuration file

Driver interface for getting memory parameters, eg. hard_limit,
soft_limit and swap_hard_limit based on cgroup support

Driver interface for setting memory hard_limit, soft_limit and swap
hard_limit based on cgroup support

Adding parsing code for memory tunables in the domain xml file
also change the internal define structures used for domain memory
informations
Adds a new specific test

Public api to set/get memory tunables supported by the hypervisors.

dv:
* some cleanups in libvirt.c
* adding extra checks in libvirt.c new entry points

v4:
* Move exporting public API to this patch
* Add unsigned int flags to the public api for future extensions

v3:
* Add domainGetMemoryParamters and NULL in all the driver interface

v2:
* Initialize domainSetMemoryParameters to NULL in all the driver
  interface structure.

A QEMU guest can have upto VIR_DOMAIN_BOOT_LAST boot entries
defined. When building the QEMU arg, each entry takes a
single byte. This means the array must be declared to be
VIR_DOMAIN_BOOT_LAST+1 bytes in length to allow for the
trailing null

* src/qemu/qemu_conf.c: Fix off-by-1 boot arg array size

QMP in QEMU 0.13 has been fixed to enforce type correctness,
this means that boolean types must be true or false, not
integers.
Signed-off-by: NLuiz Capitulino <lcapitulino@redhat.com>

QMP in QEMU 0.13 has been fixed to enforce type correctness,
this means that boolean types must be true or false, not
integers.
Signed-off-by: NLuiz Capitulino <lcapitulino@redhat.com>

Other drivers will need this same functionality, so move it to up to
conf/domain_conf.c and give it a more general name.
Signed-off-by: NSoren Hansen <soren@linux2go.dk>

Previously QEMU enabled KQEMU by default and had -no-kqemu.
0.11.x switched to requiring -enable-kqemu. 0.12.x dropped
kqemu entirely. This patch adds support for -enable-kqemu
so 0.11.x works. It replaces a huge set of if() with a
switch() to make the code a bit more readable.

* src/qemu/qemu_conf.c, src/qemu/qemu_conf.h: Support
  -enable-kqemu

We already filled the PCI address structure when we checked whether it's
free or not, so let's just use the structure here instead of filling it
again.

* src/qemu/qemu_driver.c (qemudGetProcessInfo): Clean up.
* src/uml/uml_driver.c (umlGetProcessInfo): Likewise.
* src/xen/sexpr.c (_string2sexpr): Likewise.

The current version of the qemu managed save implementation
is subject to a race where the domain shuts down between
the time that we start the command and the time that we
actually try to do the save.  Close this race by making
qemuDomainSaveFlags() expect both the driver and the passed-in
vm object to be locked before executing.
Signed-off-by: NChris Lalancette <clalance@redhat.com>

This also makes the message consistent with the message used in error
path of qemudDomainAttachHostPciDevice.

When reconnecting to existing VMs, we re-reserved only those PCI
addresses which were explicitly mentioned in domain XML. Since some
addresses are always reserved (e.g., 0:0:0 and 0:0:1), we need to handle
those too.

Also all this should only be done if device flag is supported by qemu.

In this patch I am extending and fixing the nwfilter module's reload support to stop all ongoing threads (for learning IP addresses of interfaces) and rebuild the filtering rules of all interfaces of all VMs when libvirt is started. Now libvirtd rebuilds the filters upon the SIGHUP signal and libvirtd restart.

About the patch: The nwfilter functions require a virConnectPtr. Therefore I am opening a connection in qemudStartup, which later on needs to be closed outside where the driver lock is held since otherwise it ends up in a deadlock due to virConnectClose() trying to lock the driver as well.

I have tested this now for a while with several machines running and needing the IP address learner thread(s). The rebuilding of the firewall rules seems to work fine following libvirtd restart or a SIGHUP. Also the termination of libvirtd worked fine.

Since the qemu process is running as qemu:qemu, it can't actually
look at the unix socket in /var/run/libvirt/qemu which is owned by
root and has permission 700.  Move the unix socket to
/var/lib/libvirt/qemu, which is already owned by qemu:qemu.

Thanks to Justin Clift for test this out for me.
Signed-off-by: NChris Lalancette <clalance@redhat.com>

The problem is that on the source of the migration, libvirtd
is responsible for creating the unix socket over which the data
will flow.  Since libvirtd is running as root, this file will
be created as root.  When the qemu process running as qemu:qemu
goes to access the unix file to write data to it, it will get
permission denied and fail.  Make sure to change the owner
of the unix file to qemu:qemu.

Thanks to Justin Clift for testing this patch out for me.
Signed-off-by: NChris Lalancette <clalance@redhat.com>

 Basically a followup of the previous patch about balloon desactivation
if desactivated, to not ask for balloon information to qemu as we will
just get an error back.
 This can make a huge difference in the time needed for domain
information or list when a machine is loaded, and balloon has been
desactivated in the guests.

* src/qemu/qemu_driver.c: do not get the balloon info if the balloon
  suppor is disabled

  The balloon device is automatically added to qemu guests if supported,
but it may be useful to desactivate it. The simplest to not change the
existing behaviour is to allow
  <memballoon type="none"/>
as an extra option to desactivate it (it is automatically added if the
memballoon construct is missing for the domain).
The following simple patch just adds the extra option and does not
change the default behaviour but avoid creating a balloon device if
type="none" is used.

* docs/schemas/domain.rng: add the extra type attribute value
* src/conf/domain_conf.c src/conf/domain_conf.h: add the extra enum
  value
* src/qemu/qemu_conf.c: if enum is NONE, don't activate the device,
  i.e. don't pass the args to qemu/kvm

device_del command is not synchronous for PCI devices, it merely asks
the guest to release the device and returns. If the host wants to use
that device before the guest actually releases it, we are in big
trouble. To avoid this, we already added a loop which waits up to 10
seconds until the device is actually released before we do anything else
with that device. But we only added this loop for managed PCI devices
before we try reattach them back to the host.

However, we need to wait even for non-managed devices. We don't reattach
them automatically, but we still want to prevent the host from using it.
This was revealed thanks to sVirt: when we relabel sysfs files
corresponding to the PCI device before the guest finished releasing the
device, qemu is no longer allowed to access those files and if it wants
(as a result of guest's request) to write anything to them, it just
exits, which kills the guest.

This is not a proper fix and needs some further work both on libvirt and
qemu side in the future.

Fix the error checking to use the return value from brAddTap() instead
of checking the current errno value which might have been changed by
clean up calls inside of brAddTap().
Signed-off-by: NDoug Goldstein <cardoe@gentoo.org>

Added a more detailed error message when adding a tap devices fails and
the kernel is missing tun support.
Signed-off-by: NDoug Goldstein <cardoe@gentoo.org>

the followup on the boot=on problem, basically it's not needed to
specify it when booting out of IDE devices when using KVM
* src/qemu/qemu_conf.c: do not use boot=on for IDE devices
* tests/qemuxml2argvdata/qemuxml2argv*.args: this changes the output
  for 5 of the tests

Patch version revamped by Eric Blake <eblake@redhat.com> of Jiri
Denemark <jdenemar@redhat.com> original patch

When attaching a PCI device which doesn't explicitly set its PCI
address, libvirt allocates the address automatically. The problem is
that when checking which PCI address is unused, we only check for those
with slot number higher than the highest slot number ever used.

Thus attaching/detaching such device several times in a row (31 is the
theoretical limit, less then 30 tries are enough in practise) makes any
further device attachment fail. Furthermore, attaching a device with
predefined PCI address to 0:0:31 immediately forbids attachment of any
PCI device without explicit address.

This patch changes the logic so that we always check all PCI addresses
before we say there is no PCI address available.

Modifications from v1: revert back to remembering the last slot
reserved, but allow wraparound to not be limited by the end.
In this way, slots are still assigned in the same order as
before the patch, rather than filling in the gaps closest to
0 and risking making windows guests mad.

* src/qemu/qemu_conf.c: fix pci reservation code to do a round-robbin
  check of all available PCI splot availability before failing.

Spotted by clang.  Regression introduced in commit e72cc3c1.

* src/qemu/qemu_driver.c (qemuConnectMonitor): Don't lose error status.

Spotted by clang.

* src/qemu/qemu_monitor.c (qemuMonitorClose): Kill dead store.
* src/qemu/qemu_driver.c (qemudDomainSaveImageStartVM): Likewise.

  Basically the 'boot=on' boot selection device is something present in
KVM but not in upstream QEmu, as a result if we boot a QEmu domain
without KVM acceleration we must disable boot=on ... even if the front
end kvm binary expose that capability in the help page.

* src/qemu/qemu_conf.c: in qemudBuildCommandLine if -no-kvm
  is passed, then deactivate QEMUD_CMD_FLAG_DRIVE_BOOT

ADD_ARG_LIT should only be used for literal arguments,
since it duplicates the memory.  Since virBufferContentAndReset
is already allocating memory, we should only use ADD_ARG.
Signed-off-by: NChris Lalancette <clalance@redhat.com>

If detecting the FLR flag of a pci device fails, then we
could run into the situation of trying to close a file
descriptor twice, once in pciInitDevice() and once in pciFreeDevice().
Fix that by removing the pciCloseConfig() in pciInitDevice() and
just letting pciFreeDevice() handle it.

Thanks to Chris Wright for pointing out this problem.

While we are at it, fix an error check.  While it would actually
work as-is (since success returns 0), it's still more clear to
check for < 0 (as the rest of the code does).
Signed-off-by: NChris Lalancette <clalance@redhat.com>

Enable specifying a virtio console device with:

<console type='pty'>
  <target type='virtio'/>
</console>

All <console> devices now export a <target> type attribute. QEMU defaults
to 'serial', UML defaults to 'uml, xen can be either 'serial' or 'xen'
depending on fullvirt. Understandably there is lots of test fallout.

This will be used to differentiate between a serial vs. virtio console for
QEMU.
Signed-off-by: NCole Robinson <crobinso@redhat.com>

targetType only tracks the actual <target> format we are parsing. Currently
we only fill abide this value for channel devices.
Signed-off-by: NCole Robinson <crobinso@redhat.com>

There is actually a difference between the character device type (serial,
parallel, channel, ...) and the target type (virtio, guestfwd). Currently
they are awkwardly conflated.

Start to pull them apart by renaming targetType -> deviceType. This is
an entirely mechanical change.
Signed-off-by: NCole Robinson <crobinso@redhat.com>

Signed-off-by: NChris Lalancette <clalance@redhat.com>