When idx is 0 virStorageFileChainLookup returns the base (bottom) of the
backing chain rather than the top. This is expected by the callers of
qemuDomainGetStorageSourceByDevstr.

Add a special case for idx == 0

For guests that use <memoryBacking><locked>, our only option
is to remove the memory locking limit altogether.

Partially-resolves: https://bugzilla.redhat.com/1431793

Instead of having a separate function, we can simply return
zero from the existing qemuDomainGetMemLockLimitBytes() to
signal the caller that the memory locking limit doesn't need
to be set for the guest.

Having a single function instead of two makes it less likely
that we will use the wrong value, which is exactly what
happened when we started applying the limit that was meant
for VFIO-using guests to <memoryBacking><locked>-using
guests.

This reverts commit c2e60ad0.

Turns out this check is excessively strict: there are ways
other than <memtune><hard_limit> to raise the memory locking
limit for QEMU processes, one prominent example being
tweaking /etc/security/limits.conf.

Partially-resolves: https://bugzilla.redhat.com/1431793

Since mdevs are just another type of VFIO devices, we should increase
the memory locking limit the same way we do for VFIO PCI devices.
Signed-off-by: NErik Skultety <eskultet@redhat.com>

As goes for all the other hostdev device types, grant the qemu process
access to /dev/vfio/<mediated_device_iommu_group>.
Signed-off-by: NErik Skultety <eskultet@redhat.com>

A mediated device will be identified by a UUID (with 'model' now being
a mandatory <hostdev> attribute to represent the mediated device API) of
the user pre-created mediated device. We also need to make sure that if
user explicitly provides a guest address for a mdev device, the address
type will be matching the device API supported on that specific mediated
device and error out with an incorrect XML message.

The resulting device XML:
<devices>
  <hostdev mode='subsystem' type='mdev' model='vfio-pci'>
    <source>
      <address uuid='c2177883-f1bb-47f0-914d-32a22e3a8804'>
    </source>
  </hostdev>
</devices>
Signed-off-by: NErik Skultety <eskultet@redhat.com>

The code is currently simple, but if we later add node names, it will be
necessary to generate the names based on the node name. Add a helper so
that there's a central point to fix once we add self-generated node
names.

Looks up a disk and its corresponding backing chain element by node
name.

If the migration flags indicate this migration will be using TLS,
then set up the destination during the prepare phase once the target
domain has been started to add the TLS objects to perform the migration.

This will create at least an "-object tls-creds-x509,endpoint=server,..."
for TLS credentials and potentially an "-object secret,..." to handle the
passphrase response to access the TLS credentials. The alias/id used for
the TLS objects will contain "libvirt_migrate".

Once the objects are created, the code will set the "tls-creds" and
"tls-hostname" migration parameters to signify usage of TLS.

During the Finish phase we'll be sure to attempt to clear the
migration parameters and delete those objects (whether or not they
were created). We'll also perform the same reset during recovery
if we've reached FINISH3.

If the migration isn't using TLS, then be sure to check if the
migration parameters exist and clear them if so.

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

Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

So, majority of the code is just ready as-is. Well, with one
slight change: differentiate between dimm and nvdimm in places
like device alias generation, generating the command line and so
on.

Speaking of the command line, we also need to append 'nvdimm=on'
to the '-machine' argument so that the nvdimm feature is
advertised in the ACPI tables properly.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

NVDIMM is new type of memory introduced into QEMU 2.6. The idea
is that we have a Non-Volatile memory module that keeps the data
persistent across domain reboots.

At the domain XML level, we already have some representation of
'dimm' modules. Long story short, NVDIMM will utilize the
existing <memory/> element that lives under <devices/> by adding
a new attribute 'nvdimm' to the existing @model and introduce a
new <path/> element for <source/> while reusing other fields. The
resulting XML would appear as:

    <memory model='nvdimm'>
      <source>
        <path>/tmp/nvdimm</path>
      </source>
      <target>
        <size unit='KiB'>523264</size>
        <node>0</node>
      </target>
      <address type='dimm' slot='0'/>
    </memory>

So far, this is just a XML parser/formatter extension. QEMU
driver implementation is in the next commit.

For more info on NVDIMM visit the following web page:

    http://pmem.io/Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

https://bugzilla.redhat.com/show_bug.cgi?id=1431112

Yeah, that's right. A mount point doesn't have to be a directory.
It can be a file too. However, the code that tries to preserve
mount points under /dev for new namespace for qemu does not count
with that option.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

https://bugzilla.redhat.com/show_bug.cgi?id=1430634

If a qemu process has died, we get EOF on its monitor. At this
point, since qemu process was the only one running in the
namespace kernel has already cleaned the namespace up. Any
attempt of ours to enter it has to fail.

This really happened in the bug linked above. We've tried to
attach a disk to qemu and while we were in the monitor talking to
qemu it just died. Therefore our code tried to do some roll back
(e.g. deny the device in cgroups again, restore labels, etc.).
However, during the roll back (esp. when restoring labels) we
still thought that domain has a namespace. So we used secdriver's
transactions. This failed as there is no namespace to enter.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

When libvirtd is started we call qemuDomainRecheckInternalPaths
to detect whether a domain has VNC socket path generated by libvirt
based on option from qemu.conf.  However if we are parsing status XML
for running domain the existing socket path can be generated also if
the config XML uses the new <listen type='socket'/> element without
specifying any socket.

The current code doesn't make difference how the socket was generated
and always marks it as "fromConfig".  We need to store the
"autoGenerated" value in the status XML in order to preserve that
information.

The difference between "fromConfig" and "autoGenerated" is important
for migration, because if the socket is based on "fromConfig" we don't
print it into the migratable XML and we assume that user has properly
configured qemu.conf on both hosts.  However if the socket is based
on "autoGenerated" it means that a new feature was used and therefore
we need to leave the socket in migratable XML to make sure that if
this feature is not supported on destination the migration will fail.
Signed-off-by: NPavel Hrdina <phrdina@redhat.com>

Rename 'secretUsageType' to 'usageType' since it's superfluous in an
API qemu*Secret*

Building upon the qemuDomainSecretInfoNew, create a helper which will
build the secret used for TLS.
Signed-off-by: NJohn Ferlan <jferlan@redhat.com>

Create a helper which will create the secinfo used for disks, hostdevs,
and chardevs.
Signed-off-by: NJohn Ferlan <jferlan@redhat.com>

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

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

Now that we have some qemuSecurity wrappers over
virSecurityManager APIs, lets make sure everybody sticks with
them. We have them for a reason and calling virSecurityManager
API directly instead of wrapper may lead into accidentally
labelling a file on the host instead of namespace.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

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>

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>

The bare fact that mnt namespace is available is not enough for
us to allow/enable qemu namespaces feature. There are other
requirements: we must copy all the ACL & SELinux labels otherwise
we might grant access that is administratively forbidden or vice
versa.
At the same time, the check for namespace prerequisites is moved
from domain startup time to qemu.conf parser as it doesn't make
much sense to allow users to start misconfigured libvirt just to
find out they can't start a single domain.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

mknod() is affected my the current umask, so we're not
guaranteed the newly-created device node will have the
right permissions.

Call chmod(), which is not affected by the current umask,
immediately afterwards to solve the issue.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1421036

This controller only allows up to 15 ports.

https://bugzilla.redhat.com/show_bug.cgi?id=1375417

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>

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>

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

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