This patch introduces keep alive messages support for P2P migration
and it adds two new configuration entries namely 'keepalive_interval'
'keepalive_count' to control it. Behavior of these entries is the
same as qemu driver thus the description is copied from there
with just a few simplifications.
Signed-off-by: NJoao Martins <joao.m.martins@oracle.com>

Introduce support for VIR_MIGRATE_PEER2PEER in libvirt migration.
Most of the changes occur at the source and no modifications at
the receiver.

In P2P mode there is only the Perform phase so we must handle the
connection with the destination and actually perform the
migration. libxlDomainPerformP2P implements the connection to the
destination and libxlDoMigrateP2P implements the actual migration
logic with virConnectPtr. In this function we take care of doing
all phases of migration in the destination similar to
virDomainMigrateVersion3Full. We appropriately save the last
error reported in each of the phases to provide proper reporting.
We don't yet support VIR_MIGRATE_TUNNELED and we always use V3
with extensible params, thus it also makes the implementation
simpler.

It is worth noting that the receiver didn't have any changes, and
since it's still the v3 sequence thus it is possible to migrate
from a P2P to non-P2P host.
Signed-off-by: NJoao Martins <joao.m.martins@oracle.com>

The virDomainObjFormat and virDomainSaveStatus methods
both call into virDomainDefFormat, so should be providing
a non-NULL virCapsPtr instance.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

And use the newly added caps->host.netprefix (if it exists) for
interface names that match the autogenerated target names.
Signed-off-by: NJoao Martins <joao.m.martins@oracle.com>

Remove redundant error reporting in libxlDomainMigrationPerform().
virNetSocketNewConnectTCP() is perfectly capable of reporting
sensible errors.

Commit f86ae403 moved acquiring a job from libxlDomainStart()
to its callers. One spot missed was in libxlDoMigrateReceive().
Acquire a job in libxlDoMigrateReceive() before calling
libxlDomainStart().
Signed-off-by: NJim Fehlig <jfehlig@suse.com>

Failure of libxl_domain_suspend() does not leave the domain in
a suspended state, so no need to call libxl_domain_resume(),
which btw will fail with "domain not suspended".
Signed-off-by: NJim Fehlig <jfehlig@suse.com>

This patch fixes some flawed logic around ref counting the
libxlMigrationDstArgs object.

First, when adding sockets to the event loop with
virNetSocketAddIOCallback(), the generic virObjectFreeCallback()
was registered as a free function, with libxlMigrationDstArgs as
its parameter. A reference was also taken on
libxlMigrationDstArgs for each successful call to
virNetSocketAddIOCallback(). The rational behind this logic was
that the libxlMigrationDstArgs object had to out-live the socket
objects. But virNetSocketAddIOCallback() already takes a
reference on socket objects, ensuring their life until removed
from the event loop and unref'ed in virNetSocketEventFree(). We
only need to ensure libxlMigrationDstArgs lives until
libxlDoMigrateReceive() finishes, which can be done by simply
unref'ing libxlMigrationDstArgs at the end of
libxlDoMigrateReceive().

The second flaw was unref'ing the sockets in the failure path of
libxlMigrateReceive() and at the end of libxlDoMigrateReceive().
As mentioned above, the sockets are already unref'ed by
virNetSocketEventFree() when removed from the event loop.
Attempting to unref the socket a second time resulted in a
libvirtd crash since the socket was previously unref'ed and
disposed.
Signed-off-by: NJim Fehlig <jfehlig@suse.com>

Set the state of virDomainObj in the functions that
actually change the domain state, instead of the generic
libxlDomainCleanup function. This approach gives functions
calling libxlDomainCleanup more flexibility wrt when and
how they change virDomainObj state via virDomainObjSetState.

The prior approach of calling virDomainObjSetState in
libxlDomainCleanup resulted in the following incorrect
coding pattern in the various functions that change
domain state

 libxlDomain<DoStateTransition>
   call libxl function to do state transition
   emit lifecycle event
   libxlDomainCleanup
     virDomainObjSetState

Once simple manifestation of this bug is seeing a domain
running in virt-manager after selecting the shutdown button,
even after the domain has long shutdown.

By default, getaddrinfo() will return addresses for both
IPv4 and IPv6 if both protocols are enabled, and so the
RPC code will listen/connect to both protocols too. There
may be cases where it is desirable to restrict this to
just one of the two protocols, so add an 'int family'
parameter to all the TCP related APIs.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

The returned socks from virNetSocketNewListenTCP needs to be VIR_FREE'd
as well as seach of the Close/Unref on all the socks[i] that is
already done

Provide integration with libvirt's lock manager in the libxl driver.
Signed-off-by: NJim Fehlig <jfehlig@suse.com>

This needs to specified in way too many places for a simple validation
check. The ostype/arch/virttype validation checks later in
DomainDefParseXML should catch most of the cases that this was covering.

A destroy operation can take considerable time on large memory
domains due to scrubbing the domain's memory.  Unlock the
virDomainObj while libxl_domain_destroy is executing.

Implement libxlDomainDestroyInternal wrapper to handle unlocking,
calling destroy, and locking.  Change all callers of
libxl_domain_destroy to use the wrapper.
Signed-off-by: NJim Fehlig <jfehlig@suse.com>

Although needed in the Xen 4.1 libxl days, there is no longer any
benefit to having per-domain libxl_ctx.  On the contrary, their use
makes the code unecessarily complicated and prone to deadlocks under
load.  As suggested by the libxl maintainers, use a single libxl_ctx
as a handle to libxl instead of per-domain ctx's.

One downside to using a single libxl_ctx is there are no longer
per-domain log files for log messages emitted by libxl.  Messages
for all domains will be sent to /var/log/libvirt/libxl/libxl-driver.log.
Signed-off-by: NJim Fehlig <jfehlig@suse.com>

The virDomainDefParse* and virDomainDefFormat* methods both
accept the VIR_DOMAIN_XML_* flags defined in the public API,
along with a set of other VIR_DOMAIN_XML_INTERNAL_* flags
defined in domain_conf.c.

This is seriously confusing & error prone for a number of
reasons:

 - VIR_DOMAIN_XML_SECURE, VIR_DOMAIN_XML_MIGRATABLE and
   VIR_DOMAIN_XML_UPDATE_CPU are only relevant for the
   formatting operation
 - Some of the VIR_DOMAIN_XML_INTERNAL_* flags only apply
   to parse or to format, but not both.

This patch cleanly separates out the flags. There are two
distint VIR_DOMAIN_DEF_PARSE_* and VIR_DOMAIN_DEF_FORMAT_*
flags that are used by the corresponding methods. The
VIR_DOMAIN_XML_* flags received via public API calls must
be converted to the VIR_DOMAIN_DEF_FORMAT_* flags where
needed.

The various calls to virDomainDefParse which hardcoded the
use of the VIR_DOMAIN_XML_INACTIVE flag change to use the
VIR_DOMAIN_DEF_PARSE_INACTIVE flag.

Commit id 'cb88d433' refactored the calling sequence to use a thread;
however, in doing so "lost" the check for if virNetSocketAccept returns
failure.  Since other code makes that check, Coverity complains. Although
a false positive, adding back the failure check pacifies Coverity

This patch contains three domain cleanup improvements in the migration
finish phase, ensuring a domain is properly disposed when a failure is
detected or the migration is cancelled.

The check for virDomainObjIsActive is moved to libxlDomainMigrationFinish,
where cleanup can occur if migration failed and the domain is inactive.

The 'cleanup' label was missplaced in libxlDomainMigrationFinish, causing
a migrated domain to remain in the event of an error or cancelled migration.

In cleanup, the domain was not removed from the driver's list of domains.
Signed-off-by: NJim Fehlig <jfehlig@suse.com>

During the perform phase of migration, the domain is started on
the dst host in a running state if VIR_MIGRATE_PAUSED flag is not
specified.  In the finish phase, the domain is also unpaused if
VIR_MIGRATE_PAUSED flag is unset.  I've noticed this second unpause
fails if the domain was already unpaused following the perform phase.

This patch changes the perform phase to always start the domain
paused, and defers unpausing, if requested, to the finish phase.
Unpausing should occur in the finish phase anyhow, where the domain
can be properly destroyed if the perform phase fails and migration
is cancelled.
Signed-off-by: NJim Fehlig <jfehlig@suse.com>

Moving data reception of the perform phase of migration to a
thread introduces a race with the finish phase, where checking
if the domain is active races with the thread finishing the
perform phase.  The race is easily solved by acquiring a job in
the finish phase, which must wait for the perform phase job to
complete.

While wrapping the finish phase in a job, noticed the virDomainObj
was being unlocked in a callee - libxlDomainMigrationFinish.  Move
the unlocking to libxlDomainMigrateFinish3Params, where the lock
is acquired.
Signed-off-by: NJim Fehlig <jfehlig@suse.com>

The libxl driver receives migration data within an IO callback invoked
by the event loop, effectively disabling the event loop while migration
occurs.

This patch moves receving of the migration data to a thread.  The
incoming connection is still accepted in the IO callback, but control
is immediately returned to the event loop after spawning the thread.
Signed-off-by: NJim Fehlig <jfehlig@suse.com>

With all the changes in my previous foray into this code, I forgot to
remove the libxlDomainEventQueue(driver, event); call inside the
dom == NULL condition.
Signed-off-by: NJohn Ferlan <jferlan@redhat.com>

Coverity noted that all callers to libxlDomainEventQueue() could ensure
the second parameter (event) was true before calling except this case.
As I look at the code and how events are used - it seems that prior to
generating an event for the dom == NULL condition, the resume/suspend
event should be queue'd after the virDomainSaveStatus() call which will
goto cleanup and queue the saved event anyway.
Signed-off-by: NJohn Ferlan <jferlan@redhat.com>

In libxlDomainMigrationPrepare() if the uri_in is false, then
'hostname' is allocated and used "generically" in the routine,
but not freed.  Conversely, if uri_in is true, then a uri is
allocated and hostname is set to the uri->hostname value and
likewise generically used.

At function exit, hostname wasn't free'd in the !uri_in path,
so that was added.  To just make it clearer on usage the else
path became the call to virURIFree() although I suppose technically
it didn't have to since it would be a call using (NULL)

In libxlDomainMigrationConfirm(), a transient domain is removed
from the domain list after successful migration.  Later in cleanup,
the domain object is unlocked, resulting in a crash

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0x7fb4208ed700 (LWP 12044)]
0x00007fb4267251e6 in virClassIsDerivedFrom (klass=0xdeadbeef,
  parent=0x7fb42830d0c0) at util/virobject.c:169
169	        if (klass->magic == parent->magic)
(gdb) bt
0  0x00007fb4267251e6 in virClassIsDerivedFrom (klass=0xdeadbeef,
  parent=0x7fb42830d0c0) at util/virobject.c:169
1  0x00007fb42672591b in virObjectIsClass (anyobj=0x7fb4100082b0,
  klass=0x7fb42830d0c0) at util/virobject.c:365
2  0x00007fb42672583c in virObjectUnlock (anyobj=0x7fb4100082b0)
  at util/virobject.c:338
3  0x00007fb41a8c7d7a in libxlDomainMigrationConfirm (driver=0x7fb4100404c0,
  vm=0x7fb4100082b0, flags=1, cancelled=0) at libxl/libxl_migration.c:583

Fix by setting the virDomainObjPtr to NULL after removing it from
the domain list.

During migration, the libxl driver starts a modify job in the
begin phase, ending the job in the confirm phase.  This is
essentially VIR_MIGRATE_CHANGE_PROTECTION semantics, but the
driver does not support that flag.  Without CHANGE_PROTECTION
support, the job would never be terminated in error conditions
where migrate confirm phase is not executed.  Further attempts
to modify the domain would result in failure to acquire a job
after LIBXL_JOB_WAIT_TIME.

Similar to the qemu driver, end the job in the begin phase.
Protecting the domain object across all phases of migration can
be done in a future patch adding CHANGE_PROTECTION support.

In libxlDomainMigrationPrepare(), a new virDomainObj is created
from the incoming domain def and added to the driver's domain
list, but never removed if there are subsequent failures during
the prepare phase.

targethost# virsh list --all

sourcehost# virsh migrate --live dom xen+ssh://targethost/system
   error: operation failed: Fail to create socket for incoming migration.

targethost# virsh list --all
error: Failed to list domains
error: name in virGetDomain must not be NULL

After adding code to remove the domain on prepare failure, noticed
that libvirtd crashed due to double free of the virDomainDef.  Similar
to the qemu driver, pass a pointer to virDomainDefPtr so it can be set
to NULL once a virDomainObj is created from it.

In libxlDomainMigrationPrepare(), the cleanup label handles error
conditions and should be renamed as such for clarity.

Migration code specifies the problematic non-cooperative resume mode
which is a known issue with Xen's libxl [1].  Instead, use the better
supported cooperative mode.

Without this, guests BUG() in xen_irq_resume after failing to bind
still-bound event channels.

[1] http://bugs.xenproject.org/xen/bug/30

Resolve two Coverity issues introduced by commit id '9b8d6e1e'
Signed-off-by: NJohn Ferlan <jferlan@redhat.com>

This patch adds initial migration support to the libxl driver,
using the VIR_DRV_FEATURE_MIGRATION_PARAMS family of migration
functions.
Signed-off-by: NJim Fehlig <jfehlig@suse.com>