Commit Graph

670 Commits

Author SHA1 Message Date
Daniel P. Berrangé
5b13570ab8 conf: introduce callback registration for domain net device allocation
Currently virt drivers will call directly into the network driver impl
to allocate domain interface devices where type=network. This introduces
a callback system to allow us to decouple the virt drivers from the
network driver.

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
2018-02-09 11:05:10 +00:00
Jim Fehlig
0c710a37ea libxl: resume lock process after failed migration
During migration, the lock process is paused in the perform phase
but not resumed if there is a subsequent failure, leaving the locked
resource unprotected.

The perform phase itself can fail, in which case the lock process
should be resumed before returning from perform. The finish phase
could also fail on the destination host, in which case the migration
is canceled in the confirm phase and the VM is resumed. The lock
process needs to be resumed there as well.

Signed-off-by: Jim Fehlig <jfehlig@suse.com>
2018-01-25 09:22:14 -07:00
Jim Fehlig
69ed99c786 libxl: mark domain0 as persistent
A Xen domain0 is better described as a persistent domain. Mark it
as such during intialization.
2017-12-15 15:25:01 -07:00
Marek Marczykowski-Górecki
82ef04fe79 libxl: add support for multiple IP addresses
vif-* scripts support it for a long time, and expect addresses to be
separated by spaces. Add appropriate support to libxl driver.

Reviewed-by: Jim Fehlig <jfehlig@suse.com>
2017-12-08 13:55:07 -07:00
Wim ten Have
c9a5682ffa libxl: vnuma support
This patch generates a NUMA distance-aware libxl description from the
information extracted from a NUMA distance-aware libvirt XML file.

By default, if no NUMA node distance information is supplied in the
libvirt XML file, this patch uses the distances 10 for local and 20
for remote nodes/sockets.

Signed-off-by: Wim ten Have <wim.ten.have@oracle.com>
Reviewed-by: Jim Fehlig <jfehlig@suse.com>
Signed-off-by: Jim Fehlig <jfehlig@suse.com>
2017-11-12 19:39:18 -07:00
Peter Krempa
5af63c9aa3 conf: Fix type for @liveStatus in virDomainObjListLoadAllConfigs
Use bool instead of an int.
2017-11-09 10:37:58 +01:00
Peter Krempa
90521d0754 storage: Store RBD image name as pool and image name
Similarly to how we store gluster names, split the name into a pool and
image portions when paring the XML and store them separately.
2017-11-07 14:58:04 +01:00
Andrea Bolognani
3e7db8d3e8 Remove backslash alignment attempts
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>
2017-11-03 13:24:12 +01:00
Pavel Hrdina
8c85b1ed4a conf: merge virDomainLifecycleCrashAction with virDomainLifecycleAction
There is no need to have two different enums where one has the same
values as the other one with some additions.

Currently for on_poweroff and on_reboot we allow only subset of actions
that are allowed for on_crash.  This was covered in parse time using
two different enums.  Now to make sure that we don't allow setting
actions that are not supported we need to check it while validating
domain config.

Reviewed-by: John Ferlan <jferlan@redhat.com>
Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
2017-10-19 11:52:09 +02:00
Pavel Hrdina
21068580d6 conf: rename lifecycle enum values to correspond with typedef keyword
Reviewed-by: John Ferlan <jferlan@redhat.com>
Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
2017-10-19 11:51:53 +02:00
Jiri Denemark
a62dca833e cpu: Drop unused parameter from cpuDecode
The "preferred" parameter is not used by any caller of cpuDecode
anymore. It's only used internally in cpu_x86 to implement cpuBaseline.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
2017-10-16 09:21:52 +02:00
Jiri Denemark
fd885a06a0 cpu: Use virDomainCapsCPUModelsPtr in cpu driver APIs
All APIs which expect a list of CPU models supported by hypervisors were
switched from char **models and int models to just accept a pointer to
virDomainCapsCPUModels object stored in domain capabilities. This avoids
the need to transform virDomainCapsCPUModelsPtr into a NULL-terminated
list of model names and also allows the various cpu driver APIs to
access additional details (such as its usability) about each CPU model.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
2017-10-16 09:21:52 +02:00
Michal Privoznik
be9978bb89 virDomainInterfaceStats: Accept MAC addresses properly
https://bugzilla.redhat.com/show_bug.cgi?id=1497396

In 0d3d020ba6 I've added capability to accept MAC addresses
for the API too. However, the implementation was faulty. It needs
to lookup the corresponding interface in the domain definition
and pass the ifname instead of MAC address.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
2017-10-13 17:54:50 -07:00
Michal Privoznik
0d3d020ba6 virDomainInterfaceStats: Accept MAC address too
https://bugzilla.redhat.com/show_bug.cgi?id=1497396

The other APIs accept both, ifname and MAC address. There's no
reason virDomainInterfaceStats can't do the same.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
2017-10-13 13:46:59 -07:00
Michal Privoznik
e3909729d2 virDomainNetFind: Report error if no device found
Every caller reports the error themselves. Might as well move it
into the function and thus unify it.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
2017-10-13 13:46:36 -07:00
caoxinhua
0248098d38 Fix 1 << -1 in JOB_MASK macro
Calling JOB_MASK(QEMU_JOB_NONE) would result in 1 << -1.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
2017-10-12 15:53:56 +02:00
Michal Privoznik
d86fd2402e virNetDevTapInterfaceStats: Allow caller to not swap the statistics
https://bugzilla.redhat.com/show_bug.cgi?id=1497410

The comment in virNetDevTapInterfaceStats() implementation for
Linux states that packets transmitted by domain are received by
the host and vice versa. Well, this is true but not for all types
of interfaces. For instance, for macvtaps when TAP device is
hooked right onto a physical device any packet that domain sends
looks also like a packet sent to the host. Therefore, we should
allow caller to chose if the stats returned should be straight
copy or swapped.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
2017-10-05 09:16:05 +02:00
Michal Privoznik
c2c47b586f src: Use virDomainNetFindByName
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: John Ferlan <jferlan@redhat.com>
2017-10-05 09:16:05 +02:00
Jiri Denemark
4fd179f518 cpu_conf: Drop updateCPU from virCPUDefFormat
In the past we updated host-model CPUs with host CPU data by adding a
model and features, but keeping the host-model mode. And since the CPU
model is not normally formatted for host-model CPU defs, we had to pass
the updateCPU flag to the formatting code to be able to properly output
updated host-model CPUs. Libvirt doesn't do this anymore, host-model
CPUs are turned into custom mode CPUs once updated with host CPU data
and thus there's no reason for keeping the hacks inside CPU XML
formatters.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
2017-09-21 15:23:39 +02:00
Ashish Mittal
029c36c981 storage: Introduce VIR_STORAGE_NET_PROTOCOL_VXHS
Add a new virStorageNetProtocol for Veritas HyperScale (VxHS) disks

Signed-off-by: Ashish Mittal <Ashish.Mittal@veritas.com>
Signed-off-by: John Ferlan <jferlan@redhat.com>
2017-09-19 21:10:21 -04:00
Jiri Denemark
abec725ab1 cpu: Drop cpuBaselineXML
The implementation of virConnectBaselineCPU may be different for each
hypervisor. Thus it shouldn't really be implmented in the cpu code.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
2017-09-18 10:40:12 +02:00
Andrea Bolognani
bc0108845c docs: Fix typo deamon -> daemon
Suggested-by: Martin Kletzander <mkletzan@redhat.com>
Signed-off-by: Andrea Bolognani <abologna@redhat.com>
Reviewed-by: Martin Kletzander <mkletzan@redhat.com>
2017-09-04 15:07:17 +02:00
George Dunlap
92b6c99223 libxl: Avoid a variable named 'stat'
Using a variable named 'stat' clashes with the system function
'stat()' causing compiler warnings on some platforms:

libxl/libxl_driver.c: In function 'libxlDomainBlockStatsVBD':
libxl/libxl_driver.c:5387: error: declaration of 'stat' shadows a global declaration [-Wshadow]
/usr/include/sys/stat.h:455: error: shadowed declaration is here [-Wshadow]

Signed-off-by: George Dunlap <george.dunlap@citrix.com>
Reviewed-by: Andrea Bolognani <abologna@redhat.com>
2017-08-24 16:22:27 +02:00
Ján Tomko
e9f3222705 introduce virConfReadString
Rewrite virConfReadMem to take a null-terminated string.
All the callers were calling strlen on it anyway.
2017-08-08 12:19:17 +02:00
Martin Kletzander
6e6faf6d62 conf: Pass config.priv to xmlopt->privateData.alloc
This will help us to get to some data more easily.

Signed-off-by: Martin Kletzander <mkletzan@redhat.com>
2017-07-25 17:02:27 +02:00
Peter Krempa
97ea8da183 virStorageNetHostDef: Turn @port into integer
Currently, @port is type of string. Well, that's overkill and
waste of memory. Port is always an integer. Use it as such.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
2017-07-24 10:55:44 +02:00
Daniel P. Berrange
d8f8c7a83d Remove network constants out of internal.h
The HOST_NAME_MAX, INET_ADDRSTRLEN and VIR_LOOPBACK_IPV4_ADDR
constants are only used by a handful of files, so are better
kept in virsocketaddr.h or the source file that uses them.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2017-07-11 13:57:11 +01:00
John Ferlan
2065499b60 events: Avoid double free possibility on remote call failure
If a remote call fails during event registration (more than likely from
a network failure or remote libvirtd restart timed just right), then when
calling the virObjectEventStateDeregisterID we don't want to call the
registered @freecb function because that breaks our contract that we
would only call it after succesfully returning.  If the @freecb routine
were called, it could result in a double free from properly coded
applications that free their opaque data on failure to register, as seen
in the following details:

    Program terminated with signal 6, Aborted.
    #0  0x00007fc45cba15d7 in raise
    #1  0x00007fc45cba2cc8 in abort
    #2  0x00007fc45cbe12f7 in __libc_message
    #3  0x00007fc45cbe86d3 in _int_free
    #4  0x00007fc45d8d292c in PyDict_Fini
    #5  0x00007fc45d94f46a in Py_Finalize
    #6  0x00007fc45d960735 in Py_Main
    #7  0x00007fc45cb8daf5 in __libc_start_main
    #8  0x0000000000400721 in _start

The double dereference of 'pyobj_cbData' is triggered in the following way:

    (1) libvirt_virConnectDomainEventRegisterAny is invoked.
    (2) the event is successfully added to the event callback list
        (virDomainEventStateRegisterClient in
        remoteConnectDomainEventRegisterAny returns 1 which means ok).
    (3) when function remoteConnectDomainEventRegisterAny is hit,
        network connection disconnected coincidently (or libvirtd is
        restarted) in the context of function 'call' then the connection
        is lost and the function 'call' failed, the branch
        virObjectEventStateDeregisterID is therefore taken.
    (4) 'pyobj_conn' is dereferenced the 1st time in
        libvirt_virConnectDomainEventFreeFunc.
    (5) 'pyobj_cbData' (refered to pyobj_conn) is dereferenced the
         2nd time in libvirt_virConnectDomainEventRegisterAny.
    (6) the double free error is triggered.

Resolve this by adding a @doFreeCb boolean in order to avoid calling the
freeCb in virObjectEventStateDeregisterID for any remote call failure in
a remoteConnect*EventRegister* API. For remoteConnect*EventDeregister* calls,
the passed value would be true indicating they should run the freecb if it
exists; whereas, it's false for the remote call failure path.

Patch based on the investigation and initial patch posted by
fangying <fangying1@huawei.com>.
2017-06-25 08:16:04 -04:00
Marc Hartmayer
adf846d3c9 Use ATTRIBUTE_FALLTHROUGH
Use ATTRIBUTE_FALLTHROUGH, introduced by commit
5d84f5961b, instead of comments to
indicate that the fall through is an intentional behavior.

Signed-off-by: Marc Hartmayer <mhartmay@linux.vnet.ibm.com>
Reviewed-by: Boris Fiuczynski <fiuczy@linux.vnet.ibm.com>
Reviewed-by: Bjoern Walk <bwalk@linux.vnet.ibm.com>
2017-06-12 19:11:30 -04:00
Jiri Denemark
25af7e950a conf: Add save cookie callbacks to xmlopt
virDomainXMLOption gains driver specific callbacks for parsing and
formatting save cookies.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
2017-06-07 13:36:01 +02:00
Michal Privoznik
4f0aeed871 virDomainXMLOption: Introduce virDomainABIStabilityDomain
While checking for ABI stability, drivers might pose additional
checks that are not valid for general case. For instance, qemu
driver might check some memory backing attributes because of how
qemu works. But those attributes may work well in other drivers.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
2017-06-05 09:08:52 +02:00
Jim Fehlig
6de895f64c libxl: add default controllers for USB devices
Attempting to start a domain with USB hostdevs but no USB controllers
fails with the rather cryptic error

libxl: error: libxl_qmp.c:287:qmp_handle_error_response: received an
error message from QMP server: Bus 'xenusb-0.0' not found

This can be fixed by creating default USB controllers. When no USB
controllers are defined, create the number of 8 port controllers
necessary to accommodate the number of defined USB devices.

Note that USB controllers are already created as needed in the
domainAttachDevice code path. E.g. a USB controller will be created,
if necessary, when attaching a USB device with
'virsh attach-device dom usbdev.xml'.
2017-05-23 14:29:16 -06:00
Jim Fehlig
dbb85e0c15 libxl: add default listen address for VNC and spice
If a VNC listen address is not specified in domXML, libxl
will default to 127.0.0.1, but this is never reflected in the domXML.
In the case of spice, a missing listen address resulted in listening
on all interfaces, i.e. '0.0.0.0'. If not specified, set the listen
address in virDomainGraphicsDef struct to the libxl default when
creating the frame buffer device. Additionally, set default spice
listen address to 127.0.0.1.
2017-05-22 10:20:27 -06:00
Wim ten Have
bf12395230 libxl: report numa sibling distances on host capabilities
When running on a NUMA machine, populate the sibling node
and distance information using data supplied by Xen.

With locality distances information, under Xen, new host
capabilities would like:

    <topology>
      <cells num='4'>
        <cell id='0'>
          <memory unit='KiB'>263902380</memory>
          <distances>
            <sibling id='0' value='10'/>
            <sibling id='1' value='21'/>
          </distances>
          ...
        </cell>
        ...
      </cells>
      ...
    </topology>

Signed-off-by: Wim ten Have <wim.ten.have@oracle.com>
Reviewed-by: Joao Martins <joao.m.martins@oracle.com>
Reviewed-by: Jim Fehlig <jfehlig@suse.com>
2017-05-10 17:15:25 -06:00
Wim ten Have
c268b9eaeb libxl: set nestedhvm for mode host-passthrough
Xen feature nestedhvm is the option on Xen 4.4+ which enables
nested virtualization when mode host-passthrough is applied.

nested HVM is enabled by adding below on the target domain;
<cpu mode='host-passthrough'/>

Virtualization on target domain can be disabled by specifying
such under feature policy rule on target name;

[On Intel (VT-x) architecture]
<feature policy='disable' name='vmx'/>

or:

[On AMD (AMD-V) architecture]
<feature policy='disable' name='svm'/>

Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
Signed-off-by: Wim ten Have <wim.ten.have@oracle.com>
2017-04-27 15:05:44 -06:00
Michal Privoznik
5683b21309 virGetDomain: Set domain ID too
So far our code is full of the following pattern:

  dom = virGetDomain(conn, name, uuid)
  if (dom)
      dom->id = 42;

There is no reasong why it couldn't be just:

  dom = virGetDomain(conn, name, uuid, id);

After all, client domain representation consists of tuple (name,
uuid, id).

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
2017-04-03 08:35:57 +02:00
Martin Kletzander
bdcb199532 Move src/fdstream to src/util/virfdstream
There is no reason for it not to be in the utils, all global symbols
under that file already have prefix vir* and there is no reason for it
to be part of DRIVER_SOURCES because that is just a leftover from
older days (pre-driver modules era, I believe).

Signed-off-by: Martin Kletzander <mkletzan@redhat.com>
2017-03-27 13:13:29 +02:00
Guido Günther
b2aca2db7e libxl: fix typo in debug message 2017-03-16 10:50:38 +01:00
Jiri Denemark
d3f831a97a cpu_x86: Make virCPUx86DataAddCPUID work with virCPUDataPtr
The CPU driver provides APIs to create and free virCPUDataPtr. Thus all
APIs exported from the driver should work with that rather than
requiring the caller to pass a pointer to an internal part of the
structure.

In other words

    virCPUx86DataAddCPUID(cpudata, &cpuid)

is much better than the original

    virCPUx86DataAddCPUID(&cpudata->data.x86, &cpuid)

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
2017-02-24 14:10:57 +01:00
Jiri Denemark
f6d55a5f42 cpu: Rework cpuDataFree
The new API is called virCPUDataFree. Individual CPU drivers are no
longer required to implement their own freeing function unless they need
to free architecture specific data from virCPUData.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
2017-02-24 14:10:57 +01:00
Jiri Denemark
035d81b10a cpu_x86: Drop virCPUx86MakeData and use virCPUDataNew
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
2017-02-24 14:10:57 +01:00
Daniel P. Berrange
dd08d9ffe8 libxl: fix empty string check for channel path
The libxl code was checking that a 'char *' was != '\0', instead
of checking the first element in the string

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2017-02-23 10:11:16 +00:00
Joao Martins
1e6bc3c581 libxl: fix coverity issues introduced by 6a95edf
As discussed here [0][1] Coverity reported two issues:

- On libxlDomainMigrationPrepareTunnel3 @@mig will be leaked on failures
after sucessfull call libxlDomainMigrationPrepareAny hence we free it.

Setting mig = NULL after @mig is assigned plus adding libxlMigrationCookieFree
on error paths addresses the issue. In case virThreadCreate fails,
unref of args frees the cookie on dispose function (libxlMigrationDstArgsDispose)

- On libxlMigrationStartTunnel @tc would be leaked.

Fixed by correctly saving the newly allocated @tc onto @tnl such that
libxlMigrationStopTunnel would free it up.

[0] https://www.redhat.com/archives/libvir-list/2017-February/msg00791.html
[1] https://www.redhat.com/archives/libvir-list/2017-February/msg00833.html

Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
2017-02-16 12:19:35 -05:00
Jim Fehlig
2dc1cf19db libxl: fix potential double free in libxlDriverGetDom0MaxmemConf
Commit 4ab0c959 fixed a memory leak in libxlDriverGetDom0MaxmemConf
but introduced a potential double free of mem_tokens

*** Error in `/usr/sbin/libvirtd': double free or corruption (out):
    0x00007fffc808cfd0 ***

Avoid double free by setting mem_tokens to NULL after calling
virStringListFree.
2017-02-15 18:24:58 -07:00
Bob Liu
6a95edf9ab libxl: add tunnelled migration support
Tunnelled migration doesn't require any extra network connections
beside the libvirt daemon.  It's capable of strong encryption and the
default option of openstack-nova.

This patch adds the tunnelled migration(Tunnel3params) support to
libxl.  On the source side, the data flow is:

 * libxlDoMigrateSend() -> pipe libxlTunnel3MigrationFunc() polls pipe
 * out and then write to dest stream.

While on the destination side:
 * Stream -> pipe -> 'recvfd of libxlDomainStartRestore'

The usage is the same as p2p migration, execpt adding one extra
'--tunnelled' to the libvirt p2p migration command.

Signed-off-by: Bob Liu <bob.liu@oracle.com>
Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
2017-02-15 14:47:14 -07:00
Joao Martins
d2100f2b4a libxl: refactor libxlDomainMigrationPrepare
The newly introduced function libxlDomainMigrationPrepareAny
will be shared between P2P and tunnelled variations.

Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
2017-02-15 10:15:50 -07:00
John Ferlan
4ab0c959e9 libxl: Resolve possible resource leak in dom0 maximum memory setting
If either the "if (STRPREFIX(mem_tokens[j], "max:"))" is never entered
or the "if (virStrToLong_ull(mem_tokens[j] + 4, &p, 10, maxmem) < 0)" break
is hit, control goes back to the outer loop processing 'cmd_tokens' and
it's possible that the 'mem_tokens' would be overwritten.

Found by Coverity
2017-02-10 14:11:04 -05:00
Jim Fehlig
79692c3874 libxl: fix dom0 maximum memory setting
When the libxl driver is initialized, it creates a virDomainDef
object for dom0 and adds it to the list of domains. Total memory
for dom0 was being set from the max_memkb field of libxl_dominfo
struct retrieved from libxl, but this field can be set to
LIBXL_MEMKB_DEFAULT (~0ULL) if dom0 maximum memory has not been
explicitly set by the user.

This patch adds some simple parsing of the Xen commandline,
looking for a dom0_mem parameter that also specifies a 'max' value.
If not specified, dom0 maximum memory is effectively all physical
host memory.

Signed-off-by: Jim Fehlig <jfehlig@suse.com>
2017-02-09 10:02:19 -07:00
Jim Fehlig
d2b77608e9 libxl: fix reporting of maximum memory
The libxl driver reports different values of maximum memory depending
on state of a domain. If inactive, maximum memory value is reported
correctly. When active, maximum memory is derived from max_pages value
returned by the XEN_SYSCTL_getdomaininfolist sysctl operation. But
max_pages can be changed by toolstacks and does not necessarily
represent the maximum memory a domain can use during its active
lifetime.

A better location for determining a domain's maximum memory is the
/local/domain/<id>/memory/static-max node in xenstore. This value
is set from the libxl_domain_build_info.max_memkb field when creating
the domain. Currently it cannot be changed nor can its value be
exceeded by a balloon operation. From libvirt's perspective, always
reporting maximum memory with virDomainDefGetMemoryTotal() will produce
the same results as reading the static-max node in xenstore.

Signed-off-by: Jim Fehlig <jfehlig@suse.com>
2017-02-09 09:38:34 -07:00
Jim Fehlig
bd1168101a libxl: fix disk detach when <driver> not specified
When a user does not explicitly set a <driver> in the disk config,
libvirt defers selection of a default to libxl. This approach works
fine when starting a domain with such configuration or attaching a
disk to a running domain. But when detaching such a disk, libxl
will fail with "unrecognized disk backend type: 0". libxl makes no
attempt to recalculate a default backend (driver) on detach and
simply fails when uninitialized.

This patch updates the libvirt disk config with the backend selected
by libxl when starting a domain or attaching a disk to a running
domain. Another benefit of this approach is that the live XML is
also updated with the backend driver selected by libxl.
2017-02-09 09:24:44 -07:00