Fix for bug https://bugzilla.redhat.com/show_bug.cgi?id=618970
The "prepare" hook is called very early in the VM statup process
before device labeling, so that it can allocate ressources not
managed by libvirt, such as DRBD, or for instance create missing
bridges and vlan interfaces.
* src/util/hooks.c src/util/hooks.h: add definitions for new hooks
VIR_HOOK_QEMU_OP_PREPARE and VIR_HOOK_QEMU_OP_RELEASE
* src/qemu/qemu_process.c: use them in qemuProcessStart and
qemuProcessStop()
THREADS.txt states that the contents of vm should not be read or
modified while the vm lock is not held, but that the lock must not
be held while performing a monitor command. This fixes all the
offenders that I could find.
* src/qemu/qemu_process.c (qemuProcessStartCPUs)
(qemuProcessInitPasswords, qemuProcessStart): Don't modify or
refer to vm state outside lock.
* src/qemu/qemu_driver.c (qemudDomainHotplugVcpus): Likewise.
* src/qemu/qemu_hotplug.c (qemuDomainChangeGraphicsPasswords):
Likewise.
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.
This was also found while investigating
https://bugzilla.redhat.com/show_bug.cgi?id=670848
An EOF on a domain's monitor socket results in an event being queued
to handle the EOF. The handler calls qemuProcessHandleMonitorEOF. If
it is a transient domain, this leads to a call to
virDomainRemoveInactive, which removes the domain from the driver's
hashtable and unref's it. Nowhere in this code is the qemu driver lock
acquired.
However, all modifications to the driver's domain hashtable *must* be
done while holding the driver lock, otherwise the hashtable can become
corrupt, and (even more likely) another thread could call a different
hashtable function and acquire a pointer to the domain that is in the
process of being destroyed.
To prevent such a disaster, qemuProcessHandleMonitorEOF must get the
qemu driver lock *before* it gets the DomainObj's lock, and hold it
until it is finished with the DomainObj. This guarantees that nobody
else modifies the hashtable at the same time, and that anyone who had
already gotten the DomainObj from the hashtable prior to this call has
finished with it before we remove/destroy it.
This was found while researching the root cause of:
https://bugzilla.redhat.com/show_bug.cgi?id=670848
virDomainUnref should only be called with the lock held for the
virDomainObj in question. However, when a transient qemu domain gets
EOF on its monitor socket, it queues an event which frees the monitor,
which unref's the virDomainObj without first locking it. If another
thread has already locked the virDomainObj, the modification of the
refcount could potentially be corrupted. In an extreme case, it could
also be potentially unlocked by virDomainObjFree, thus left open to
modification by anyone else who would have otherwise waited for the
lock (not to mention the fact that they would be accessing freed
data!).
The solution is to have qemuMonitorFree lock the domain object right
before unrefing it. Since the caller to qemuMonitorFree doesn't expect
this lock to be held, if the refcount doesn't go all the way to 0,
qemuMonitorFree must unlock it after the unref.
Relax the restriction that the hash table key must be a string
by allowing an arbitrary hash code generator + comparison func
to be provided
* util/hash.c, util/hash.h: Allow any pointer as a key
* internal.h: Include stdbool.h as standard.
* conf/domain_conf.c, conf/domain_conf.c,
conf/nwfilter_params.c, nwfilter/nwfilter_gentech_driver.c,
nwfilter/nwfilter_gentech_driver.h, nwfilter/nwfilter_learnipaddr.c,
qemu/qemu_command.c, qemu/qemu_driver.c,
qemu/qemu_process.c, uml/uml_driver.c,
xen/xm_internal.c: s/char */void */ in hash callbacks
This is done for two reasons:
- we are getting very close to 64 flags which is the maximum we can use
with unsigned long long
- by using LL constants in enum we already violates C99 constraint that
enum values have to fit into int
Done mechanically with:
$ git grep -l '\bDEBUG0\? *(' | xargs -L1 sed -i 's/\bDEBUG0\? *(/VIR_&/'
followed by manual deletion of qemudDebug in daemon/libvirtd.c, along
with a single 'make syntax-check' fallout in the same file, and the
actual deletion in src/util/logging.h.
* src/util/logging.h (DEBUG, DEBUG0): Delete.
* daemon/libvirtd.h (qemudDebug): Likewise.
* global: Change remaining clients over to VIR_DEBUG counterpart.
Now that the virHash handling functions call virReportOOMError by
themselves when needed, users of the virHash API no longer need to
do it by themselves. Since users of the virHash API were not
consistently calling virReportOOMError after memory failures from
the virHash code, this has the added benefit of making OOM
reporting from this code more consistent and reliable.
Move the qemudStartVMDaemon and qemudShutdownVMDaemon
methods into a separate file, renaming them to
qemuProcessStart, qemuProcessStop. All helper methods
called by these are also moved & renamed to match
* src/Makefile.am: Add qemu_process.c/.h
* src/qemu/qemu_command.c: Add qemuDomainAssignPCIAddresses
* src/qemu/qemu_command.h: Add VNC port min/max
* src/qemu/qemu_domain.c, src/qemu/qemu_domain.h: Add
domain event queue helpers
* src/qemu/qemu_driver.c, src/qemu/qemu_driver.h: Remove
all QEMU process startup/shutdown functions
* src/qemu/qemu_process.c, src/qemu/qemu_process.h: Add
all QEMU process startup/shutdown functions
