Add a new storage driver registration function that will force the
backend code to fail if any of the storage backend modules can't be
loaded. This will make sure that they work and are present.

If driver modules are enabled turn storage driver backends into
dynamically loadable objects. This will allow greater modularity for
binary distributions, where heavyweight dependencies as rbd and gluster
can be avoided by selecting only a subset of drivers if the rest is not
necessary.

The storage modules are installed into 'LIBDIR/libvirt/storage-backend/'
and users can override the location by using
'LIBVIRT_STORAGE_BACKEND_DIR' environment variable.

rpm based distros will at this point install all the backends when
libvirt-daemon-driver-storage package is installed.

Our virSomeEnumTypeFromString() functions return either the value
of item from the enum or -1 on error. Usually however the value 0
means 'this value is not set in the domain XML, use some sensible
default'. Therefore, we don't accept corresponding string in
domain XML, for instance:

<memoryBacking>
  <source mode="none"/>
  <access mode="default"/>
  <allocation mode="none"/>
</memoryBacking>

should be rejected as invalid XML.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

Fix a leak introduced by 4337bc57 when VIR_STRDUP'g the parent.

Rather than the inlined VIR_FREE's, use a cleanup: label... Fixes an
issue introduced by 03346def where @name was free'd before usage in
a virAsprintf to format scsi_host_name.

The functions in virCommand() after fork() must be careful with regard
to accessing any mutexes that may have been locked by other threads in
the parent process. It is possible that another thread in the parent
process holds the lock for the virQEMUDriver while fork() is called.
This leads to a deadlock in the child process when
'virQEMUDriverGetConfig(driver)' is called and therefore the handshake
never completes between the child and the parent process. Ultimately
the virDomainObjectPtr will never be unlocked.

It gets much worse if the other thread of the parent process, that
holds the lock for the virQEMUDriver, tries to lock the already locked
virDomainObject. This leads to a completely unresponsive libvirtd.

It's possible to reproduce this case with calling 'virsh start XXX'
and 'virsh managedsave XXX' in a tight loop for multiple domains.

This commit fixes the deadlock in the same way as it is described in
commit 61b52d2e.
Signed-off-by: NMarc Hartmayer <mhartmay@linux.vnet.ibm.com>
Reviewed-by: NBoris Fiuczynski <fiuczy@linux.vnet.ibm.com>

Add code that validates user's selection of cores and then uses the
existing code to plug in the vCPU.

Similarly to domainSetGuestVcpus this commit adds API which allows to
modify state of individual vcpus rather than just setting the count.

This allows to enable CPUs in specific guest NUMA nodes to achieve any
necessary configuration.

Signed-off-by: NMartin Kletzander <mkletzan@redhat.com>

With that users could access files outside /dev/shm.  That itself
isn't a security problem, but might cause some errors we want to
avoid.  So let's forbid slashes as we do with domain and volume names
and also mention that in the schema.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1395496Signed-off-by: NMartin Kletzander <mkletzan@redhat.com>

Compile the storage driver into modules rather than by compiling all
files together. All modules are still linked together statically.

Add APIs that allow to dynamically register driver backends so that the
list of available drivers does not need to be known during compile time.

This will allow us to modularize the storage driver on runtime.

Pass the registration function name to virDriverLoadModule so that we
can later call specific functions if necessary (e.g. for testing
purposes). This gets rid of the rather ugly automatic name generator and
unifies the code to load/initialize the modules.

It's also clear which registration function gets called.

Split the convoluted driver loader function into simpler parts which
will potentially allow reuse.

The niothreadids struct field is size_t, so must use %zu not %lu
with printf. While they're identical on some platforms, on others
they are different, causing warnings

conf/domain_conf.c: In function 'virDomainDefCheckABIStabilityFlags':
conf/domain_conf.c:19575:26: error: format '%lu' expects argument of type 'long unsigned int', but argument 7 has type 'size_t {aka unsigned int}' [-Werror=format=]
                        _("Target domain iothreads count %lu does not "
                          ^

conf/domain_conf.c: In function 'virDomainDefFormatInternal':
conf/domain_conf.c:23915:46: error: format '%lu' expects argument of type 'long unsigned int', but argument 3 has type 'size_t {aka unsigned int}' [-Werror=format=]
         virBufferAsprintf(buf, "<iothreads>%lu</iothreads>\n",
                                              ^
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Signed-off-by: NPavel Hrdina <phrdina@redhat.com>

This follows the same check for disk, because we cannot remove iothread
if it's used by disk or by controller.  It could lead to crashing QEMU.
Signed-off-by: NPavel Hrdina <phrdina@redhat.com>

Signed-off-by: NPavel Hrdina <phrdina@redhat.com>

If virDomainDelIOThread API was called with VIR_DOMAIN_AFFECT_LIVE
and VIR_DOMAIN_AFFECT_CONFIG and both XML were already a different
it could result in removing iothread from config XML even if there
was a disk using that iothread.
Signed-off-by: NPavel Hrdina <phrdina@redhat.com>

This will ensure that IOThreads are properly validated while
a domain is defined.
Signed-off-by: NPavel Hrdina <phrdina@redhat.com>

The situation covered by the removed code will not ever happen.
This code is called only while starting a new QEMU process where
the capabilities where already checked and while attaching to
existing QEMU process where we don't even detect the iothreads.
Signed-off-by: NPavel Hrdina <phrdina@redhat.com>

Signed-off-by: NPavel Hrdina <phrdina@redhat.com>

Signed-off-by: NPavel Hrdina <phrdina@redhat.com>

Signed-off-by: NPavel Hrdina <phrdina@redhat.com>

Signed-off-by: NPavel Hrdina <phrdina@redhat.com>

Signed-off-by: NPavel Hrdina <phrdina@redhat.com>

Signed-off-by: NPavel Hrdina <phrdina@redhat.com>

The utils code should stay separated from other code (except for very
well justified cases). Unfortunately commit 272769be
made it trivial to break the separation (and not get slapped by the
syntax-check rule) by adding -I src/conf to the CFLAGS for utils.

Remove this shortcut and except the two offenders from the syntax check
so that the codebase can be kept separated.

The comment was actually wrong as
https://www.freedesktop.org/software/systemd/man/udev_new.html#
mentions that on failure NULL is returned.  Also the same return value
is checked in src/interface/interface_backend_udev.c already.
Signed-off-by: NMarc Hartmayer <mhartmay@linux.vnet.ibm.com>

When enabling virgl, qemu opens /dev/dri/render*. So far, we are
not allowing that in devices CGroup nor creating the file in
domain's namespace and thus requiring users to set the paths in
qemu.conf. This, however, is suboptimal as it allows access to
ALL qemu processes even those which don't have virgl configured.
Now that we have a way to specify render node that qemu will use
we can be more cautious and enable just that.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

So far, qemuDomainGetHostdevPath has no knowledge of the reasong
it is called and thus reports /dev/vfio/vfio for every VFIO
backed device. This is suboptimal, as we want it to:

a) report /dev/vfio/vfio on every addition or domain startup
b) report /dev/vfio/vfio only on last VFIO device being unplugged

If a domain is being stopped then namespace and CGroup die with
it so no need to worry about that. I mean, even when a domain
that's exiting has more than one VFIO devices assigned to it,
this function does not clean /dev/vfio/vfio in CGroup nor in the
namespace. But that doesn't matter.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>
Reviewed-by: NMarc-André Lureau <marcandre.lureau@redhat.com>

So far, we are allowing /dev/vfio/vfio in the devices cgroup
unconditionally (and creating it in the namespace too). Even if
domain has no hostdev assignment configured. This is potential
security hole. Therefore, when starting the domain (or
hotplugging a hostdev) create & allow /dev/vfio/vfio too (if
needed).
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>
Reviewed-by: NMarc-André Lureau <marcandre.lureau@redhat.com>

Since these two functions are nearly identical (with
qemuSetupHostdevCgroup actually calling virCgroupAllowDevicePath)
we can have one function call the other and thus de-duplicate
some code.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>
Reviewed-by: NMarc-André Lureau <marcandre.lureau@redhat.com>

There's no need for this function. Currently it is passed as a
callback to virSCSIVHostDeviceFileIterate(). However, SCSI host
devices have just one file path. Therefore we can mimic approach
used in qemuDomainGetHostdevPath() to get path and call
virCgroupAllowDevicePath() directly.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>
Reviewed-by: NMarc-André Lureau <marcandre.lureau@redhat.com>

There's no need for this function. Currently it is passed as a
callback to virSCSIDeviceFileIterate(). However, SCSI devices
have just one file path. Therefore we can mimic approach used in
qemuDomainGetHostdevPath() to get path and call
virCgroupAllowDevicePath() directly.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>
Reviewed-by: NMarc-André Lureau <marcandre.lureau@redhat.com>

There's no need for this function. Currently it is passed as a
callback to virUSBDeviceFileIterate(). However, USB devices have
just one file path. Therefore we can mimic approach used in
qemuDomainGetHostdevPath() to get path and call
virCgroupAllowDevicePath() directly.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>
Reviewed-by: NMarc-André Lureau <marcandre.lureau@redhat.com>

Signed-off-by: NPavel Hrdina <phrdina@redhat.com>

Add a test that allows providing the parent fabric_wwn in the input XML
in order to create the vHBA.

This also fixes a mixed setting of the fabric_wwn field from the read
test driver XML strings.

Rework the code to perform the various searches by parent, parent_wwnn/
parent_wwpn, parent_fabric_wwn, or vport capable in order to return the
'parent_host' number that is vHBA capable.

The former virNodeDeviceGetParentHost is renamed to add the ByParent
on it fixes an issue where if no parent was supplied in the XML to
create the vHBA, then virNodeDeviceFindByName was called with a NULL
second parameter which had bad results.

The reworked code will make the various calls to fetch the NPIV host
by the passed parameter options or if none are provided find a vport
capable NPIV HBA to perform the create. If the call is from the delete
path, then this option won't be allowed.

Each of virNodeDeviceGetParentHostBy* functions is now static, so
remove them external definitions.

A secondary benefit of this is the test_driver now can make use of
the new API to add some new tests to test the various creation options.

While perhaps improbable, it could be possible that after finding our
object that another thread running essentially in parallel could attempt
to delete the same vHBA.

So rather than dropping the lock right after finding the object, keep
the lock around while we drop the object lock and work on deleting the
object. Once the delete occurs we can safely drop the driver lock again.

Cleanup some of the usage of cleanup instead out for the goto label.