This part introduces new xml elements for file based
memorybacking support and their parsing.
(It allows vhost-user to be used without hugepages.)

New xml elements:
<memoryBacking>
  <source type="file|anonymous"/>
  <access mode="shared|private"/>
  <allocation mode="immediate|ondemand"/>
</memoryBacking>

Add new parameter memory_backing_dir where files will be stored when memoryBacking
source is selected as file.

Value is stored inside char* memoryBackingDir

Rename to avoid duplicate code. Because virDomainMemoryAccess will be
used in memorybacking for setting default behaviour.

NOTE: The enum cannot be moved to qemu/domain_conf because of headers
dependency

Strings associated with virDomainHyperv values in domain_conf.c are used to
construct HyperV CPU features names to be compared with names defined in
cpu_x86_data.h and the names for HyperV "spinlocks" feature don't match.
This leads to a misleading warning:
"host doesn't support hyperv 'spinlocks' feature" even when it's supported.
Let's fix it and rename along with it VIR_CPU_x86_KVM_HV_SPINLOCK to
VIR_CPU_x86_KVM_HV_SPINLOCKS.
Signed-off-by: NMaxim Nestratov <mnestratov@virtuozzo.com>

Signed-off-by: NJiri Denemark <jdenemar@redhat.com>

Signed-off-by: NJiri Denemark <jdenemar@redhat.com>

virCPUDefStealModel is called with keepVendor == true which means the
cpu structure will keep its original vendor/vendor_id values. Thus it
makes no sense to copy them to the translated definition as they won't
be used there anyway. Except that the translated->vendor pointer might
get lost in x86Decode.
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>

PARALLELS_STATISTICS_DROP_COUNT isn't used anymore
Signed-off-by: NMaxim Nestratov <mnestratov@virtuozzo.com>

When we happen to lose a domain but still get a performance event
for it, we should also free the event handle.
Signed-off-by: NMaxim Nestratov <mnestratov@virtuozzo.com>

Every successful call of PrlEvent_GetParamByName allocates a handle,
which has to be freed.
Signed-off-by: NMaxim Nestratov <mnestratov@virtuozzo.com>

Just like we need wrappers over other virSecurityManager APIs, we
need one for virSecurityManagerSetImageLabel and
virSecurityManagerRestoreImageLabel. Otherwise we might end up
relabelling device in wrong namespace.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

The typical pattern when calling libxl functions that populate a
structure is

  libxl_foo foo;
  libxl_foo_init(&foo);
  libxl_get_foo(ctx, &foo);
  ...
  libxl_foo_dispose(&foo);

Fix several instances of libxl_physinfo missing the init and
dispose calls.
Signed-off-by: NJim Fehlig <jfehlig@suse.com>

libxlGetAutoballoonConf is supposed to honor user-specified
autoballoon setting in libxl.conf. As written, the user-specified
setting could be overwritten by the subsequent logic to check
dom0_mem parameter. If user-specified setting is present and
correct, accept it. Only fallback to checking Xen dom0_mem
command line parameter if user-specfied setting is not present.
Signed-off-by: NJim Fehlig <jfehlig@suse.com>

If no graphics element is in XML xenFormatXLSpice will access
graphics without checking it has one in the first place, leading to a
segmentation fault.
Signed-off-by: NJoao Martins <joao.m.martins@oracle.com>

Firstly, instead of checking for next->path the
virStorageSourceIsEmpty() function should be used which also
takes disk type into account.
Secondly, not every disk source passed has the correct type set
(due to our laziness). Therefore, instead of checking for
virStorageSourceIsBlockLocal() and also S_ISBLK() the former can
be refined to just virStorageSourceIsLocalStorage().
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

Again, one missed bit. This time without this commit there is no
/dev entry  in the namespace of the qemu process when doing disk
snapshots or block-copy.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

These functions do not need to see the whole virDomainDiskDef.
Moreover, they are going to be called from places where we don't
have access to the full disk definition. Sticking with
virStorageSource is more than enough.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

Since its introduction in 81df2150 this variable was never
used.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

There is no need for this. None of the namespace helpers uses it.
Historically it was used when calling secdriver APIs, but we
don't to that anymore.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

This struct is unused after 095f042e.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

Again, one missed bit. This time without this commit there is no
/dev entry in the namespace of the qemu process when attaching
vhost SCSI device.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

Since we have qemuSecurity wrappers over
virSecurityManagerSetHostdevLabel and
virSecurityManagerRestoreHostdevLabel we ought to use them
instead of calling secdriver APIs directly.  Without those
wrappers the labelling won't be done in the correct namespace
and thus won't apply to the nodes seen by qemu itself.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

libvirt was able to set the host_mtu option when an MTU was explicitly
given in the interface config (with <mtu size='n'/>), set the MTU of a
libvirt network in the network config (with the same named
subelement), and would automatically set the MTU of any tap device to
the MTU of the network.

This patch ties that all together (for networks based on tap devices
and either Linux host bridges or OVS bridges) by learning the MTU of
the network (i.e. the bridge) during qemuInterfaceBridgeConnect(), and
returning that value so that it can then be passed to
qemuBuildNicDevStr(); qemuBuildNicDevStr() then sets host_mtu in the
interface's commandline options.

The result is that a higher MTU for all guests connecting to a
particular network will be plumbed top to bottom by simply changing
the MTU of the network (in libvirt's config for libvirt-managed
networks, or directly on the bridge device for simple host bridges or
OVS bridges managed outside of libvirt).

One question I have about this - it occurred to me that in the case of
migrating a guest from a host with an older libvirt to one with a
newer libvirt, the guest may have *not* had the host_mtu option on the
older machine, but *will* have it on the newer machine. I'm curious if
this could lead to incompatibilities between source and destination (I
guess it all depends on whether or not the setting of host_mtu has a
practical effect on a guest that is already running - Maxime?)

Likewise, we could run into problems when migrating from a newer
libvirt to older libvirt - The guest would have been told of the
higher MTU on the newer libvirt, then migrated to a host that didn't
understand <mtu size='blah'/>. (If this really is a problem, it would
be a problem with or without the current patch).

This resolves: https://bugzilla.redhat.com/1224348

Example:

  <network>
     ...
     <mtu size='9000'/>
     ...

If mtu is unset, it's assumed that we want the default for whatever is
the underlying transport (usually this is 1500).

This setting isn't yet wired in, so it will have no effect.

This partially resolves: https://bugzilla.redhat.com/1224348

virNetDevTapCreateInBridgePort() has always set the new tap device to
the current MTU of the bridge it's being attached to. There is one
case where we will want to set the new tap device to a different
(usually larger) MTU - if that's done with the very first device added
to the bridge, the bridge's MTU will be set to the device's MTU. This
patch allows for that possibility by adding "int mtu" to the arg list
for virNetDevTapCreateInBridgePort(), but all callers are sending -1,
so it doesn't yet have any effect.

Since the requested MTU isn't necessarily what is used in the end (for
example, if there is no MTU requested, the tap device will be set to
the current MTU of the bridge), and the hypervisor may want to know
the actual MTU used, we also return the actual MTU to the caller (if
actualMTU is non-NULL).

In order for memory locking to work, the hard limit on memory
locking (and usage) has to be set appropriately by the user.

The documentation mentions the requirement already: with this
patch, it's going to be enforced by runtime checks as well,
by forbidding a non-compliant guest from being defined as well
as edited and started.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1316774

Like it usually happens, I fixed one thing and broke another:
in 803966c7 address allocation was fixed for SATA disks, but
broke that for virtio disks, because it dropped disk address
assignment completely. It's not needed for SATA disks anymore,
but still needed for the virtio ones.

Bring that back and add a couple of tests to make sure it won't
happen again.

When working with symlinks it is fairly easy to get into a loop.
Don't.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

Similarly to one of the previous commits, we need to deal
properly with symlinks in hotplug case too.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

When working with symlinks it is fairly easy to get into a loop.
Don't.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

Imagine you have a disk with the following source set up:

/dev/disk/by-uuid/$uuid (symlink to) -> /dev/sda

After cbc45525 the transitive end of the symlink chain is
created (/dev/sda), but we need to create any item in chain too.
Others might rely on that.
In this case, /dev/disk/by-uuid/$uuid comes from domain XML thus
it is this path that secdriver tries to relabel. Not the resolved
one.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

After previous commit this has become redundant step.
Also setting up devices in namespace and setting their label
later on are two different steps and should be not done at once.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

The idea is to move all the seclabel setting to security driver.
Having the relabel code spread all over the place looks very
messy.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

Because of the nature of security driver transactions, it is
impossible to use them properly. The thing is, transactions enter
the domain namespace and commit all the seclabel changes.
However, in RestoreAllLabel() this is impossible - the qemu
process, the only process running in the namespace, is gone. And
thus is the namespace. Therefore we shouldn't use the transactions
as there is no namespace to enter.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

The current ordering is as follows:
1) set label
2) create the device in namespace
3) allow device in the cgroup

While this might work for now, it will definitely not work if the
security driver would use transactions as in that case there
would be no device to relabel in the domain namespace as the
device is created in the second step.
Swap steps 1) and 2) to allow security driver to use more
transactions.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

We will need to traverse the symlinks one step at the time.
Therefore we need to see where a symlink is pointing to.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

The comment to the function states that the errors from the child
process are reported. Well, the error buffer is filled with
possible error messages. But then it is thrown away. Among with
important error message from the child process.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

==11260== 1,006 bytes in 1 blocks are definitely lost in loss record 106 of 111
==11260==    at 0x4C2AE5F: malloc (vg_replace_malloc.c:297)
==11260==    by 0x4C2BDFF: realloc (vg_replace_malloc.c:693)
==11260==    by 0x4EA430B: virReallocN (viralloc.c:245)
==11260==    by 0x4EA7C52: virBufferGrow (virbuffer.c:130)
==11260==    by 0x4EA7D28: virBufferAdd (virbuffer.c:165)
==11260==    by 0x4EA8E10: virBufferStrcat (virbuffer.c:718)
==11260==    by 0x42D263: xenFormatXLDiskSrcNet (xen_xl.c:960)
==11260==    by 0x42D4EB: xenFormatXLDiskSrc (xen_xl.c:1015)
==11260==    by 0x42D870: xenFormatXLDisk (xen_xl.c:1101)
==11260==    by 0x42DA89: xenFormatXLDomainDisks (xen_xl.c:1148)
==11260==    by 0x42EAF8: xenFormatXL (xen_xl.c:1558)
==11260==    by 0x40E85F: testCompareParseXML (xlconfigtest.c:105)
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>