Split out the code into a separate function so that all steps for a
storage protocol are contained and the original function is easily
extendable.
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
When using blockdev the approach to base aliases will change. Add a
helper function that will aggregate all code which needs to be called
with the disk alias for the -drive to setup internal data.
qemuDomainSecretDiskPrepare wrapper is no longer necessary as the
contents were moved to a function which is designed to use the old
aliases.
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Remove the call to the validating function from the function which sets
stuff up.
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Convert the function to just prepare data for the disk. Callers need to
do the looping since there's more to do than just copy the data around.
The code path in qemuDomainPrepareDiskSource doesn't need to loop over
the chain yet, since there currently is no chain at this point. This
will be addressed later in the blockdev series where we will setup much
more stuff.
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
qemuDomainPrepareDiskSourceChain should set up the disk zero detection
mode only for the top level image. Since it's invoked also for the
middle of the chain we need to check that it's really only the top level
image.
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
When restarting libvirt would previously lose the alias of the x509
certificate object. Upon unplug we would then not delete the
corresponding objects.
Restore the alias if we know it should be there.
Luckily for disks we don't support encrypted TLS environment, so there's
no need to regenerate the 'secret' alias for decryption.
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Libvirt uses the stored alias to detach the TLS x509 object on disk
unplug. As the alias was not stored, the object would not be detached
if unplugging disks after libvirtd restart.
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Previously we did not store the aliases but rather re-generated them
when unplug was necessary. This is very cumbersome since the knowledge
when and which alias to use needs to be stored in the hotplug code as
well.
While this patch will not strictly improve this situation since there
still will be two places containing this code it at least will allow to
remove the mess from the disk-unplug code and will prevent introducing
more mess when adding blockdev support.
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Rather than trying to figure out which alias was used, store it in the
status XML.
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
We need to reference the secret objects by name when hot-unplugging
disks. Don't remove the alias so that it does not need to be
recalculated.
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
It's desired to keep the alias around to allow referencing of the secret
object used with qemu. Add set of APIs which will destroy all data
except the alias.
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Move the logic that determines which secret shall be used into the
caller and make this function work only for plain secrets.
This untangles the control flow by only checking relevant data.
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
The encryption secret is setup only for LUKS and thus requires the new
approach. Use qemuDomainSecretInfoNew for initializing it.
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Some code paths can't use the unencrypted secret. Add a helper which
checks and sets up an encrypted secret only and reuse it when setting up
the secret to decrypt the TLS private key in qemuDomainSecretInfoTLSNew.
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Rename it to qemuDomainSecretInfoNewPlain and annotate that it also may
set up a 'plain' secret in some cases. This will eventually be
refactored further.
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
The function checks whether the storage source requires authentication
secret setup. Rename it accordingly.
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Use qemuDomainSecretStorageSourcePrepare in
qemuDomainSecretHostdevPrepare as it uses a virStorageSource to prepare
the authentication secret object data.
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
This helper checks that the vm has the master key setup and libvirt
supports the given encryption algorithm.
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
My commit b8b42ca added support for formatting the vsock
command line without actually checking if it's supported.
Add it to the per-device validation function.
https://bugzilla.redhat.com/show_bug.cgi?id=1291851
Reported-by: John Ferlan <jferlan@redhat.com>
Signed-off-by: Ján Tomko <jtomko@redhat.com>
Reviewed-by: Jiri Denemark <jdenemar@redhat.com>
Create a new vsock endpoint by opening /dev/vhost-vsock,
set the requested CID via ioctl (or assign a free one if auto='yes'),
pass the file descriptor to QEMU and build the command line.
https://bugzilla.redhat.com/show_bug.cgi?id=1291851
Signed-off-by: Ján Tomko <jtomko@redhat.com>
Add a new 'vsock' element for the vsock device.
The 'model' attribute is optional.
A <source cid> subelement should be used to specify the guest cid,
or <source auto='yes'/> should be used.
https://bugzilla.redhat.com/show_bug.cgi?id=1291851
Signed-off-by: Ján Tomko <jtomko@redhat.com>
When status XML was parsed the post-parse callbacks could not access
qemu caps and potentially upgrade the definition according to the
present caps. Implement the callback to pass it in.
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Rather than a lot of checks use a switch statement. This optimizes the
code as if one device is matched the rest will certainly not match.
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Later on, more stuff will be added so prevent the main function growing
out of control.
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Allow saving various aspects necessary to do NBD migration via blockdev
by storing a 'virStorageSource' in the disk private data meant to store
the NBD target of migration. Along with this add code to parse and
format it into the status XML.
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
Extract the NBD portion of the 'job' status XML element parser into a
separate function.
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
We will be adding source data to it so extract it to a separate function.
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
Rather than always checking which path to use pre-assign it when
preparing storage source.
This reduces the need to pass 'vm' around too much. For later use the
path can be retrieved from the status XML.
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
To allow storing status information in the XML move the validation that
the 'path' is not valid for managed PR daemon case into
qemuDomainValidateStorageSource and allow parsing of the data even in
case when managed='yes'.
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Disk source definition should be validated in
qemuDomainValidateStorageSource rather than in individual generators of
command line arguments.
Change to the XML2XML test is required since now the definition is
actually validated at define time.
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Let us introduce the capability QEMU_CAPS_CCW for virtual-css-bridge
and replace QEMU_CAPS_VIRTIO_CCW with QEMU_CAPS_CCW in code segments
which identify support for ccw devices.
The virtual-css-bridge is part of the ccw support introduced in QEMU 2.7.
The QEMU_CAPS_CCW capability is based on the existence of the QEMU type.
Let us also add the capability QEMU_CAPS_CCW to the tests which
require support for ccw devices.
Signed-off-by: Shalini Chellathurai Saroja <shalini@linux.vnet.ibm.com>
Reviewed-by: Bjoern Walk <bwalk@linux.ibm.com>
Reviewed-by: Boris Fiuczynski <fiuczy@linux.ibm.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
Before we exec() qemu we have to spawn pr-helper processes for
all managed reservations (well, technically there can only one).
The only caveat there is that we should place the process into
the same namespace and cgroup as qemu (so that it shares the same
view of the system). But we can do that only after we've forked.
That means calling the setup function between fork() and exec().
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
If qemu-pr-helper is compiled with multipath support the first
thing it does is open /dev/mapper/control. Since we're going
to be running it inside qemu namespace we need to create it
there. Unfortunately, we don't know if it was compiled with or
without multipath so we have to create it anyway.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
For command line we need two things:
1) -object pr-manager-helper,id=$alias,path=$socketPath
2) -drive file.pr-manager=$alias
In -object pr-manager-helper we tell qemu which socket to connect
to, then in -drive file-pr-manager we just reference the object
the drive in question should use.
For managed PR helper the alias is always "pr-helper0" and socket
path "${vm->priv->libDir}/pr-helper0.sock".
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
Couple of reasons for that:
a) there's no monitor command to change path where the pr-helper
connects to, or
b) there's no monitor command to introduce a new pr-helper for a
disk that already exists.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
Use the new helper when checking that the VM needs to be tainted as a
host-cdrom passthrough.
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Laine Stump <laine@laine.org>
The function will be reused in the test code where we don't care much
that the gluster debug level can't be populated from the qemu config.
Set the level only when 'cfg' is passed.
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
Use virFileIsCDROM to detect whether a block device is a cdrom drive and
store it in virStorageSource. This will be necessary to correctly create
the 'host_cdrom' backend in qemu when using -blockdev.
We assume that host_cdrom makes only sense when used directly as a raw
image, but if a backing chain would be put in front of it, libvirt will
use 'host_device' in that case.
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
Move it to the validation callback and make it more robust. This will
also put the checks in the correct place to use with -blockdev.
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
Add a flag denoting that a virStorageSource is going to be used as a
floppy image. This will be useful in cases where the user passes in
files which shall be exposed as an image to the guest.
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
Some properties don't make sense to be configured for every single layer
of the backing chain, but to avoid needing to pass the disk structure we
will copy them to the individual virStorageSource.
Zero detection is applied only for the top layer image, while caching
and iomode for all layers.
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
Save and restore node names if we know them or when we will be
generating them in the status XML.
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
When adding a new object to the domain object list, there should
have been 2 virObjectRef calls made one for each list into which
the object was placed to match the 2 virObjectUnref calls that
would occur during Remove as part of virHashRemoveEntry when
virObjectFreeHashData is called when the element is removed from
the hash table as set up in virDomainObjListNew.
Some drivers (libxl, lxc, qemu, and vz) handled this inconsistency
by calling virObjectRef upon successful return from virDomainObjListAdd
in order to use virDomainObjEndAPI when done with the returned @vm.
While others (bhyve, openvz, test, and vmware) handled this via only
calling virObjectUnlock upon successful return from virDomainObjListAdd.
This patch will "unify" the approach to use virDomainObjEndAPI
for any @vm successfully returned from virDomainObjListAdd.
Because list removal is so tightly coupled with list addition,
this patch fixes the list removal algorithm to return the object
as entered - "locked and reffed". This way, the callers can then
decide how to uniformly handle add/remove success and failure.
This removes the onus on the caller to "specially handle" the
@vm during removal processing.
The Add/Remove logic allows for some logic simplification such
as in libxl where we can Remove the @vm directly rather than
needing to set a @remove_dom boolean and removing after the
libxlDomainObjEndJob completes as the @vm is locked/reffed.
Signed-off-by: John Ferlan <jferlan@redhat.com>
Reviewed-by: Erik Skultety <eskultet@redhat.com>
The virStorageFileSupportsSecurityDriver and
virStorageFileSupportsAccess currently just return a boolean
value. This is ok because they don't have any failure scenarios
but a subsequent patch is going to introduce potential failure
scenario. This changes their return type from a boolean to an
int with values -1, 0, 1.
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
The current private XML parsing code relies on the assumption
that NUMA node IDs start from 0 and are densely allocated,
neither of which is necessarily the case.
Change it so that the bitmap size is dynamically calculated by
looking at NUMA node IDs instead, which ensures all nodes will
be able to fit and thus the bitmap will be parsed successfully.
Update one of the test cases so that it would fail with the
previous approach, but passes with the new one.
Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1490158
Signed-off-by: Andrea Bolognani <abologna@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Allocated in qemuMigrationParamsNew() we need to free
priv->job.migParams when no longer needed.
==8061== 234 (192 direct, 42 indirect) bytes in 1 blocks are definitely lost in loss record 112 of 123
==8061== at 0x4C2CF26: calloc (vg_replace_malloc.c:711)
==8061== by 0x5325D05: virAlloc (viralloc.c:144)
==8061== by 0x1984F9: qemuMigrationParamsNew (qemu_migration_params.c:218)
==8061== by 0x19A352: qemuMigrationParamsParse (qemu_migration_params.c:1185)
==8061== by 0x1604D8: qemuDomainObjPrivateXMLParseJob (qemu_domain.c:2390)
==8061== by 0x160AE9: qemuDomainObjPrivateXMLParse (qemu_domain.c:2517)
==8061== by 0x5419EAE: virDomainObjParseXML (domain_conf.c:20442)
==8061== by 0x541A25E: virDomainObjParseNode (domain_conf.c:20555)
==8061== by 0x541A2FC: virDomainObjParseFile (domain_conf.c:20574)
==8061== by 0x13607D: testCompareStatusXMLToXMLFiles (qemuxml2xmltest.c:75)
==8061== by 0x14F3E8: virTestRun (testutils.c:180)
==8061== by 0x14DCD0: mymain (qemuxml2xmltest.c:1200)
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Add helper which will map values of disk cache mode to the flags which
are accepted by various parts of the qemu block layer.
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
There were two places where we'd check this independently. Move it to
the disk definition validation callback. This also fixes possible use of
NULL in a printf for network storage.
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
So far we are repeating the following lines over and over:
if (!(virSomeObjectClass = virClassNew(virClassForObject(),
"virSomeObject",
sizeof(virSomeObject),
virSomeObjectDispose)))
return -1;
While this works, it is impossible to do some checking. Firstly,
the class name (the 2nd argument) doesn't match the name in the
code in all cases (the 3rd argument). Secondly, the current style
is needlessly verbose. This commit turns example into following:
if (!(VIR_CLASS_NEW(virSomeObject,
virClassForObject)))
return -1;
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
In order to not affect running VMs, refreshing the halted state
is only performed if QEMU supports the query-cpus-fast QAPI.
Signed-off-by: Viktor Mihajlovski <mihajlov@linux.vnet.ibm.com>
Reviewed-by: Boris Fiuczynski <fiuczy@linux.vnet.ibm.com>
Reviewed-by: Marc Hartmayer <mhartmay@linux.vnet.ibm.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
Use query-cpus-fast instead of query-cpus if supported by QEMU.
Based on the QEMU_CAPS_QUERY_CPUS_FAST capability.
Signed-off-by: Viktor Mihajlovski <mihajlov@linux.vnet.ibm.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
This will help us decide what to do when libvirtd is restarted while an
async job is running.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
We store the flags passed to the API which started the migration. Let's
use them instead of a separate bool to check if post-copy migration was
requested.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
We store the flags passed to the API which started QEMU_ASYNC_JOB_DUMP
and we can use them to check whether a memory-only dump is running.
There's no need for a specific bool flag.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
When an async job is running, we sometimes need to know how it was
started to distinguish between several types of the job, e.g., post-copy
vs. normal migration. So far we added a specific bool item to
qemuDomainJobObj for such cases, which doesn't scale very well and
storing such bools in status XML would be painful so we didn't do it.
A better approach is to store the flags passed to the API which started
the async job, which can be easily stored in status XML.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
To be able to restore all migration parameters when libvirtd is
restarting during an active migration job, we need to store the original
values of all parameters (stored in priv->job.migParams) in the status
XML.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
The function checks whether QEMU supports TLS migration and stores the
original value of tls-creds parameter to priv->migTLSAlias. This is no
longer needed because we already have the original value stored in
priv->migParams.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Any job which touches migration parameters will first store their
original values (i.e., QEMU defaults) to qemuDomainJobObj to make it
easier to reset them back once the job finishes.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Since the function is tightly connected to migration, it was renamed as
qemuMigrationCapsCheck and moved to qemu_migration_params.c.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Introduced in d3db304d2e. Instead of returning immediately we
need to jump onto cleanup label where @paths is freed.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Now that we assume QEMU_CAPS_NETDEV, the only thing left to check
is whether we need to use the legacy -net syntax because of
a non-conforming armchitecture.
Signed-off-by: Ján Tomko <jtomko@redhat.com>
Reviewed-by: Andrea Bolognani <abologna@redhat.com>
This makes qemuDomainSupportsNetdev identical to
qemuDomainSupportsNicdev and leaves some code in
qemuDomainAttachNetDevice to be cleaned up later.
Signed-off-by: Ján Tomko <jtomko@redhat.com>
Reviewed-by: Andrea Bolognani <abologna@redhat.com>
Rather than VIR_ALLOC, use the New function for allocation. We
already use the Free function anyway.
Signed-off-by: John Ferlan <jferlan@redhat.com>
Reviewed-by: Laine Stump <laine@laine.org>
Reviewed-by: Marc Hartmayer <mhartmay@linux.vnet.ibm.com>
The array of strings we are building is indeed array of const
strings. We are not STRDUP()-ing them nor FREE()-ing them.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Marc Hartmayer <mhartmay@linux.vnet.ibm.com>
The new controller will not yet be used automatically by
libvirt, but at this point it's already possible to configure
a guest to use it.
Signed-off-by: Andrea Bolognani <abologna@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
The qemu command line generator code set disk caching of shareable disks
to 'none' when formatting the command line silently. Move this code to a
common place when preparing the domain definition for startup so that it
does not have to be duplicated.
The new test case shows that the actual cache mode will now be recorded
in the live XML definition.
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
This format is used by the storage driver and other hypervisors but qemu
does not have notion of the 'iso' format and libvirt does not translate
it to anything useful, so it would not work anyways. Users should use
'raw' instead.
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
This is a storage driver type, which is not handled in qemu driver
properly. For accessing directories, disk type 'dir' is used instead.
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
It will be necessary to initialize various aspects for the detected
members of the backing chain. Add a function that will handle it and
call it from qemuDomainPrepareDiskSource and qemuDomainDetermineDiskChain
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
If someone set a user alias or pcihole64 on an implicit controller,
we need to format it to migrate the domain properly.
Signed-off-by: Ján Tomko <jtomko@redhat.com>
Reported-by: Joseph Richard <Joseph.Richard@windriver.com>
S390 guests can only support a virtio-gpu-ccw device as a video
device. So set default video model type to VIR_DOMAIN_VIDEO_TYPE_VIRTIO
for S390 guests.
Signed-off-by: Farhan Ali <alifm@linux.vnet.ibm.com>
Having to repeat "./job[1]/" XPath prefix for every single element or
attribute we want to parse is suboptimal. And even more so once we
further extract code from qemuDomainObjPrivateXMLParseJob into separate
functions.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Commit dc567cc22b introduced qemuDomainObjPrivateXMLParseJob, but forgot
to move "./job[1]/@type" parsing into it.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Modernize the code by using the clever formatter rather than checking
manually when to format the end of the element.
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
The code overwrote the internal job type and then fixed it back. Since
the job type is not accessed in the code this does not make much sense.
Use the temporary value instead.
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
The qemu driver registered the helpers from util code, but it will be
necessary to format also some qemu-specific data.
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
We've implemented all existing checks, and more, in the new
function, so we can finally drop the old one.
Signed-off-by: Andrea Bolognani <abologna@redhat.com>
Reviewed-by: Laine Stump <laine@laine.org>
This change catches an invalid use of the option in our
test suite.
https://bugzilla.redhat.com/show_bug.cgi?id=1483816
Signed-off-by: Andrea Bolognani <abologna@redhat.com>
Reviewed-by: Laine Stump <laine@laine.org>
This change catches an invalid use of the option in our
test suite.
https://bugzilla.redhat.com/show_bug.cgi?id=1483816
Signed-off-by: Andrea Bolognani <abologna@redhat.com>
Reviewed-by: Laine Stump <laine@laine.org>
The existing function is renamed and called from the new one, so
that even while we're in the process of implementing new checks
all the existing ones will be performed.
Signed-off-by: Andrea Bolognani <abologna@redhat.com>
Reviewed-by: Laine Stump <laine@laine.org>
When trying to destroy a domain (e.g. because we've seen EOF on
the monitor) we try to acquire QEMU_JOB_DESTROY. However, if
max_queued is set in qemu.conf this may fail and since our code
doesn't count on that we will still report domain as active even
though the qemu process is long gone. More specifically, if we've
seen EOF on the monitor, qemuProcessHandleMonitorEOF() is called
which sends MONITOR_EOF job to the event worker pool and
unregisters monitor from the event loop. The worker pool calls
processMonitorEOFEvent() which tries to set job which may fail
due to the limit as described above.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Ensure all enum cases are listed in switch statements, or cast away
enum type in places where we don't wish to cover all cases.
Reviewed-by: John Ferlan <jferlan@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
GCC 8 became more fussy about detecting switch
fallthroughs. First it doesn't like it if you have
a fallthrough attribute that is not before a case
statement. e.g.
FOO:
BAR:
WIZZ:
ATTRIBUTE_FALLTHROUGH;
Is unacceptable as there's no final case statement,
so while FOO & BAR are falling through, WIZZ is
not falling through. IOW, GCC wants us to write
FOO:
BAR:
ATTRIBUTE_FALLTHROUGH;
WIZZ:
Second, it will report risk of fallthrough even if you
have a case statement for every single enum value, but
only if the switch is nested inside another switch and
the outer case statement has no final break. This is
is arguably valid because despite the fact that we have
cast from "int" to the enum typedef, nothing guarantees
that the variable we're switching on only contains values
that have corresponding switch labels. e.g.
int domstate = 87539319;
switch ((virDomainState)domstate) {
...
}
will not match enum value, but also not raise any kind
of compiler warning. So it is right to complain about
risk of fallthrough if no default: is present.
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
The controller model is slightly unusual in that the default value is
-1, not 0. As a result the default value is not covered by any of the
existing enum cases. This in turn means that any switch() statements
that think they have covered all cases, will in fact not match the
default value at all. In the qemuDomainDeviceCalculatePCIConnectFlags()
method this has caused a serious mistake where we fallthrough from the
SCSI controller case, to the VirtioSerial controller case, and from
the USB controller case to the IDE controller case.
By adding explicit enum constant starting at -1, we can ensure switches
remember to handle the default case.
Reviewed-by: John Ferlan <jferlan@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
During domain startup there are many places where we need to acquire
secrets. Currently code passes around a virConnectPtr, except in the
places where we pass in NULL. So there are a few codepaths where ability
to start guests using secrets will fail. Change to acquire a handle to
the secret driver when needed.
Reviewed-by: John Ferlan <jferlan@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
https://bugzilla.redhat.com/show_bug.cgi?id=1515533
We're already checking if IPv4 prefix isn't too long. But we are
not checking if it isn't too short. QEMU supports prefixes longer
than 4 (including). I haven't find anything similar related to
IPv6 in qemu sources.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
Instead of storing separately whether the feature is enabled
or not and what resizing policy should be used, store both of
them in a single place.
Signed-off-by: Andrea Bolognani <abologna@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
Instead of storing separately whether the feature is enabled
or not and what driver should be used, store both of them in
a single place.
Signed-off-by: Andrea Bolognani <abologna@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
When no GIC version is specified, we currently default to GIC v2;
however, that's not a great default, since guests will fail to
start if the hardware only supports GIC v3.
Change the behavior so that a sensible default is chosen instead.
That basically means using the same algorithm whether the user
didn't explicitly enable the GIC feature or they explicitly
enabled it but didn't specify any GIC version.
Signed-off-by: Andrea Bolognani <abologna@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
Keep them along with other arch/machine type checks for
features instead of waiting until command line generation
time.
Signed-off-by: Andrea Bolognani <abologna@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
The compiler can make sure we are handling all features.
While reworking the logic, also change error messages to a more
consistent style.
Signed-off-by: Andrea Bolognani <abologna@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
We want to perform all feature verification in a single spot, but
some of it (eg. GIC) is currently being performed at command line
generation time, and moving it to PostParse() would cause guests
to disappear. Moving verification to Validate() allows us to
side-step the issue.
Signed-off-by: Andrea Bolognani <abologna@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
This is a hard error, and should be handled as such.
Introduced in 2461476022.
Signed-off-by: Andrea Bolognani <abologna@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
Loadable drivers must never depend on each other. Over time some usage
mistakenly crept in for the storage and network drivers, but now this is
eliminated the syntax-check rules can enforce this separation once more.
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
The QEMU driver loadable module needs to be able to resolve all ELF
symbols it references against libvirt.so. Some of its symbols can only
be resolved against the storage_driver.so loadable module which creates
a hard dependancy between them. By moving the storage file backend
framework into the util directory, this gets included directly in the
libvirt.so library. The actual backend implementations are still done as
loadable modules, so this doesn't re-add deps on gluster libraries.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Refreshing the halted state can cause VM performance issues. Since
s390 is currently the only architecture with a known interest in
the halted state, we're avoiding to call QEMU on other platforms.
Signed-off-by: Viktor Mihajlovski <mihajlov@linux.vnet.ibm.com>
Since it may be possible that the state is unknown in some cases we
should store it as a tristate so that other code using it can determine
whether the state was updated.
Add an API to allow fetching the memory only dump statistics
for a job via the qemuDomainGetJobInfo API.
Reviewed-by: Jiri Denemark <jdenemar@redhat.com>
Handle a DUMP_COMPLETED event processing the status, stats, and
error string. Use the @status in order to copy the error that
was generated whilst processing the @stats data. If an error was
provided by QEMU, then use that instead.
If there's no async job, we can just ignore the data.
Reviewed-by: Jiri Denemark <jdenemar@redhat.com>
Define the qemuMonitorDumpStats as a new job JobStatsType to handle
being able to get memory dump statistics. For now do nothing with
the new TYPE_MEMDUMP.
Reviewed-by: Jiri Denemark <jdenemar@redhat.com>
Add a TYPE_SAVEDUMP so that when coalescing stats for a save or
dump we don't needlessly try to get the mirror stats for a migration.
Other conditions can still use MIGRATION and SAVEDUMP interchangably
including usage of the @migStats field to fetch/store the data.
Reviewed-by: Jiri Denemark <jdenemar@redhat.com>
Convert the stats field in _qemuDomainJobInfo to be a union. This
will allow for the collection of various different types of stats
in the same field.
When starting the async job that will end up being used for stats,
set the @statsType value appropriately. The @mirrorStats are
special and are used with stats.mig in order to generate the
returned job stats for a migration.
Using the NONE should avoid the possibility that some random
async job would try to return stats for migration even though
a migration is not in progress.
For now a migration and a save job will use the same statsType
Reviewed-by: Jiri Denemark <jdenemar@redhat.com>
Add and use qemuProcessEventFree for freeing qemuProcessEvents. This
is less error-prone as the compiler can help us make sure that for
every new enumeration value of qemuProcessEventType the
qemuProcessEventFree function has to be adapted.
All process*Event functions are *only* called by
qemuProcessHandleEvent and this function does the freeing by itself
with qemuProcessEventFree. This means that an explicit freeing of
processEvent->data is no longer required in each process*Event
handler.
The effectiveness of this change is also demonstrated by the fact that
it fixes a memory leak of the panic info data in
qemuProcessHandleGuestPanic.
Reported-by: Wang Dong <dongdwdw@linux.vnet.ibm.com>
Signed-off-by: Bjoern Walk <bwalk@linux.vnet.ibm.com>
Signed-off-by: Marc Hartmayer <mhartmay@linux.vnet.ibm.com>
Reviewed-by: Boris Fiuczynski <fiuczy@linux.vnet.ibm.com>
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Move the SATA controller check from command line building to
controller def validation. This includes copying the SATA
skip check found in qemuBuildSkipController.
Move the qemuCaps checks over to qemuDomainControllerDefValidatePCI.
This requires two test updates in order to set the correct capability
bit for an xml2xml test as well as setting up the similar capability
for the pseries memlocktest.
Excluding the qemuCaps checks, move the remainder of the checks
that validate whether the PCI definition is valid or not into
qemuDomainControllerDefValidatePCI.
Similar to the checking the modelName vs. NAME_NONE, let's make the
ModelNameTypeToString check more generic too within the checking done
in controller validation (with the same ignore certain models.
NB: We need to keep the ModelNameTypeToString fetch in command line
validation since we use it, but at least we can assume it returns
something valid now.
Move the various modelName == NAME_NONE from the command line
generation into domain controller validation. Also rather than
have multiple cases with the same check, let's make the code
more generic, but also note that it was the modelName option
that caused the failure. We also have to be sure not to check
the PCI models that we don't care about.
For the remaining checks in command line building, we can use
the field name in the error message to be more specific about
what causes the failure.
Move PCI validation checks out of qemu_command into the proper
qemu_domain validation helper.
Since there's a lot to move, we'll start slow by replicating the
pcie-root and pci-root avoidance from qemuBuildSkipController and
the first switch found in qemuBuildControllerDevStr.
Move SCSI validation from qemu_command into qemu_domain.
Rename/reorder the args in qemuCheckSCSIControllerIOThreads
to match the caller as well as fixing up the comments to
remove the previously removed qemuCaps arg.
Move the checks that various attributes are not set on any controller
other than SCSI controller using virtio-scsi model into the common
controller validate checks.
During post parse processing, let's force setting the controller
model to default value if not already set for defined controllers
(e.g. the non implicit ones).
We recently added a generic XHCI USB3 controller to QEMU, and libvirt
supports adding that controller rather than the NEC XHCI USB3
controller, but when auto-adding a USB controller to Q35 domains we
were still adding the vendor-specific NEC controller. This patch
changes to add the generic controller instead, if it's available in
the QEMU binary that will be used.
Signed-off-by: Laine Stump <laine@laine.org>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
qemuDomainDefValidateVideo() (called from qemuDomainDefValidate()) is
just a loop performing various checks on each video device. Rather
than maintaining this separate function, just fold the validations
into qemuDomainDeviceDefValidateVideo(), which is called once for each
video device.
Commit 7a931a4204 refactored the code and probably forgot to add
this line.
Signed-off-by: Marc Hartmayer <mhartmay@linux.vnet.ibm.com>
Reviewed-by: Boris Fiuczynski <fiuczy@linux.vnet.ibm.com>
virSecurityManagerDomainSetPathLabel is used to make a path known
to the security modules, but today is used interchangably for
- paths to files/dirs to be accessed directly
- paths to a dir, but the access will actually be to files therein
Depending on the security module it is important to know which of
these types it will be.
The argument allowSubtree augments the call to the implementations of
DomainSetPathLabel that can - per security module - decide if extra
actions shall be taken.
For now dac/selinux handle this as before, but apparmor will make
use of it to add a wildcard to the path that was passed.
Signed-off-by: Christian Ehrhardt <christian.ehrhardt@canonical.com>
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
https://bugzilla.redhat.com/show_bug.cgi?id=1527740
Users might use a block device as UEFI VAR store. Or even have
OVMF stored there. Therefore, when starting a domain and separate
mount namespace is used, we have to create all the /dev entries
that are configured for the domain.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
https://bugzilla.redhat.com/show_bug.cgi?id=1528502
So imagine you have /dev/blah symlink which points to /dev/sda.
You attach /dev/blah as disk to your domain. Libvirt correctly
creates the /dev/blah -> /dev/sda symlink in the qemu namespace.
However, then you detach the disk, change the symlink so that it
points to /dev/sdb and tries to attach the disk again. This time,
however, the attach fails (well, qemu attaches wrong disk)
because the code assumes that symlinks don't change. Well they
do.
This is inspired by test fix written by Eduardo Habkost.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Andrea Bolognani <abologna@redhat.com>
Since we have user aliases it may happen that users want to
change it using 'update-device'. Instead of ignoring it silently,
error out loudly. Note that we don't limit the check just for
"ua-" prefixes because users might try to change libvirt
generated aliases too.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
https://bugzilla.redhat.com/show_bug.cgi?id=1448149
If a domain has no numa nodes, that means we don't put any
memory-backend-file onto the qemu command line. That in turn
means we can't set access='shared'. Therefore, we should produce
an error instead of ignoring the setting silently.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
QEMU 2.7 and newer don't allow guests to start unless the initial
vCPUs count is a multiple of the vCPU hotplug granularity, so
validate it and report an error if needed.
Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1283700
Signed-off-by: Andrea Bolognani <abologna@redhat.com>
While at the moment we're only performing a single check that is
connected to vCPU hotplugging, we're going to introduce a second
one soon. Move the topology check underneath the capability check
to make that easier; since, after this change, the 'topologycpus'
variable doesn't need to have function scope, we move its
declaration to the inner scope as well.
The comments around the check are modified in order to explain
the different QEMU versions involved.
Signed-off-by: Andrea Bolognani <abologna@redhat.com>
VM drivers may need to store additional private data to the status XML
so that it can be restored after libvirtd restart. Since not everything
is needed add a callback infrastructure, where VM drivers can add only
stuff they need.
Note that the private data is formatted as a <privateData> sub-element
of the <disk> or <backingStore> <source> sub-element. This is done since
storing it out of band (in the VM private data) would require a complex
matching process to allow to put the data into correct place.
Move the IDE controller check from command line building to
controller def validation. Also explicitly include the avoidance
check for the implicit IDE controller from qemuBuildSkipController.
Cause the IDE case for command line building to generate a
failure if called to add an IDE since that shouldn't happen
if the Validate code did the right thing.
Move the call to qemuDomainCheckCCWS390AddressSupport from
qemuBuildControllerDevStr to qemuDomainDeviceDefValidateController.
This means we will get the qemuCaps from the driver opaque
variable passed to qemuDomainDeviceDefValidate.
Separate the logic of creating devices from their gathering.
Use this new function in qemuDomainNamespaceSetupHostdev and
qemuDomainNamespaceSetupDisk.
This patch pass event error up to the place where we can
use it. Error is passed only for sync blockjob event mode
as we can't use the error in async mode. In async mode we
just pass the event details to the client thru event API
but current blockjob event API can not carry extra parameter.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Raw local files do not pass through the backing store detector and thus
the code did not allocate the required backing store terminator for
them. Previously the terminating element would be formatted into the XML
since the default values used for the metadata allowed that. This is a
regression since a693fdba01 which was not detected in the review.
This patch also reverts all the changes in the test files.
Until now we would skip loading of the backing chain for files which
don't support backing chains only when starting up the VM. Move the
check from qemuProcessPrepareHostStorage with some adaptations so that's
always applied.
Now that <serial> and <console> on s390/s390x behave a bit more like the
other architectures, remove this extra differentation, and use sclp
console by default for new guests. New virtio consoles can still be
added, and it is actually needed because of the limited number of
instances for sclp and sclplm.
This reverts commit b1c88c1476, whose
reasons are not totally clear.
Signed-off-by: Pino Toscano <ptoscano@redhat.com>
Reviewed-by: Andrea Bolognani <abologna@redhat.com>
Reviewed-by: Bjoern Walk <bwalk@linux.vnet.ibm.com>
Introduce specific a target types with two models for the console
devices (sclp and sclplm) used in s390 and s390x guests, so isa-serial
is no more used for them.
This makes <serial> usable on s390 and s390x guests, with at most only
a single sclpconsole and one sclplmconsole devices usable in a single
guest (due to limitations in QEMU, which will enforce already at
runtime).
Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1449265
Signed-off-by: Pino Toscano <ptoscano@redhat.com>
Reviewed-by: Andrea Bolognani <abologna@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
We can finally introduce a specific target model for the pl011 device
used by mach-virt guests, which means isa-serial will no longer show
up to confuse users.
We make sure migration works in both directions by interpreting the
isa-serial target type, or the lack of target type, appropriately
when parsing the guest XML, and skipping the newly-introduced type
when formatting if for migration. We also verify that pl011 is not
used for non-mach-virt guests and add a bunch of test cases.
Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=151292
Signed-off-by: Andrea Bolognani <abologna@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
We can finally introduce a specific target model for the spapr-vty
device used by pSeries guests, which means isa-serial will no longer
show up to confuse users.
We make sure migration works in both directions by interpreting the
isa-serial target type, or the lack of target type, appropriately
when parsing the guest XML, and skipping the newly-introduced type
when formatting if for migration. We also verify that spapr-vty is
not used for non-pSeries guests and add a bunch of test cases.
This commit is best viewed with 'git show -w'.
Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1511421
Signed-off-by: Andrea Bolognani <abologna@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
Target model and target type must agree for the configuration
to make sense, so check that's actually the case and error out
otherwise.
Signed-off-by: Andrea Bolognani <abologna@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
Instead of validating each target type / address type combination
separately, create a small helper to perform the matching and
collapse all existing checks into a single one.
Signed-off-by: Andrea Bolognani <abologna@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
Instead of waiting until we get to command line generation, we can
validate the target for a char device much earlier.
Move all the checks out of qemuBuildSerialChrDeviceStr() and into
the new fuction. This will later allow us to validate the target
for platform devices.
Signed-off-by: Andrea Bolognani <abologna@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
This is the first step in getting rid of the assumption that
isa-serial is the default target type for serial devices.
Signed-off-by: Andrea Bolognani <abologna@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
Having a separate function for char device handling is better than
adding even more code to qemuDomainDeviceDefPostParse().
Signed-off-by: Andrea Bolognani <abologna@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
Reviewed-by: Marc Hartmayer <mhartmay@linux.vnet.ibm.com>
https://bugzilla.redhat.com/show_bug.cgi?id=1425757
The blockdev-add code provides a mechanism to sanely provide user
and password-secret arguments for iscsi without placing them on the
command line to be viewable by a 'ps -ef' type command or needing
to create separate -iscsi devices for each disk/volume found.
So modify the iSCSI command line building to check for the presence
of the capability in order properly setup and use the domain master
secret object to encrypt the password in a secret object and alter
the parameters for the command line to utilize.
Modify the xml2argvtest to exhibit the syntax for both disk and
hostdev configurations.
Rather than picking apart the two pieces we need/want (path, hosts,
and auth)- let's allocate/use a virStorageSourcePtr for iSCSI storage.
The end result is that qemuBuildSCSIiSCSIHostdevDrvStr doesn't need
to "fake" one for the qemuBuildNetworkDriveStr call.
Move the setup of the disk attribute to the disk source prepare function
which will allow proper usage with JSON props and move the fallback
(legacy) generating code into the block which is executed with legacy
options.
As a side-effect of this change we can clean up propagation of 'cfg'
into the command generator.
Also it's nice to see that the test output is the same even when the
value is generated in a different place.
Disk sharing between two VMs may corrupt the images if the format driver
does not support it. Check that the user declared use of a supported
storage format when they want to share the disk.
Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1511480
When doing block commit we need to allow write for members of the
backing chain so that we can commit the data into them.
qemuDomainDiskChainElementPrepare was used for this which since commit
786d8d91b4 calls qemuDomainNamespaceSetupDisk which has very adverse
side-effects, namely it relabels the nodes to the same label it has in
the main namespace. This was messing up permissions for the commit
operation since its touching various parts of a single backing chain.
Since we are are actually not introducing new images at that point add a
flag for qemuDomainDiskChainElementPrepare which will refrain from
calling to the namespace setup function.
Calls from qemuDomainSnapshotCreateSingleDiskActive and
qemuDomainBlockCopyCommon do introduce new members all calls from
qemuDomainBlockCommit do not, so the calls are anotated accordingly.
Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1506072
Most of the time it's okay to leave this up to negotiation between
the guest and the host, but in some situations it can be useful to
manually decide the behavior, especially to enforce its availability.
Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1308743
Signed-off-by: Andrea Bolognani <abologna@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
Setup everything related to disks in one place rather than calling in
from various places.
The change to ordering of the setup steps is necessary since secrets
need the master key to be present.
In 4f15707202 I've tried to make duplicates detection for
nested /dev mount better. However, I've missed the obvious case
when there are two same mount points. For instance if:
# mount --bind /dev/blah /dev/blah
# mount --bind /dev/blah /dev/blah
Yeah, very unlikely (in qemu driver world) but possible.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
This function works over domain definition and not domain object.
Its name is thus misleading.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
Right-aligning backslashes when defining macros or using complex
commands in Makefiles looks cute, but as soon as any changes is
required to the code you end up with either distractingly broken
alignment or unnecessarily big diffs where most of the changes
are just pushing all backslashes a few characters to one side.
Generated using
$ git grep -El '[[:blank:]][[:blank:]]\\$' | \
grep -E '*\.([chx]|am|mk)$$' | \
while read f; do \
sed -Ei 's/[[:blank:]]*[[:blank:]]\\$/ \\/g' "$f"; \
done
Signed-off-by: Andrea Bolognani <abologna@redhat.com>
When a user provides the backing chain, we will not need to re-detect
all the backing stores again, but should move to the end of the user
specified chain. Additionally if a user provides a full terminated chain
we should not attempt any further detection.
