Commit Graph

13186 Commits

Author SHA1 Message Date
Andrea Bolognani
d77cc21d4b systemd: Drop unnecessary uses of @sockprefix@
Now that providing the value is optional, we can remove almost
all uses.

Signed-off-by: Andrea Bolognani <abologna@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
2023-09-26 16:57:50 +02:00
Andrea Bolognani
6ed0cc1711 systemd: Drop unnecessary uses of @sockets@
For most services, the value provided explicitly matches the
documented default.

Signed-off-by: Andrea Bolognani <abologna@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
2023-09-26 16:57:50 +02:00
Ján Tomko
a9ac674eda qemu: extend filesystem XML validation
Reject readonly argument for virtiofs and quotas for all filesystems.

https://issues.redhat.com/browse/RHEL-4994
https://issues.redhat.com/browse/RHEL-4432

Signed-off-by: Ján Tomko <jtomko@redhat.com>
Reviewed-by: Andrea Bolognani <abologna@redhat.com>
2023-09-25 14:24:20 +02:00
Ján Tomko
a1a3361e3c qemu: fix indentation in qemuValidateDomainDeviceDefFS
Signed-off-by: Ján Tomko <jtomko@redhat.com>
Reviewed-by: Andrea Bolognani <abologna@redhat.com>
2023-09-25 14:24:20 +02:00
Andrea Bolognani
1839c5c46e qemu: Improve error message for failed firmware autoselection
The current message can be misleading, because it seems to suggest
that no firmware of the requested type is available on the system.

What actually happens most of the time, however, is that despite
having multiple firmwares of the right type to choose from, none
of them is suitable because of lacking some specific feature or
being incompatible with some setting that the user has explicitly
enabled.

Providing an error message that describes exactly the problem is
not feasible, since we would have to list each candidate along
with the reason why we rejected it, which would get out of hand
quickly.

As a small but hopefully helpful improvement over the current
situation, reword the error message to make it clearer that the
culprit is not necessarily the firmware type, but rather the
overall domain configuration.

Suggested-by: Michael Kjörling <7d1340278307@ewoof.net>
Signed-off-by: Andrea Bolognani <abologna@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
2023-09-22 15:50:35 +02:00
Pavel Hrdina
ed80ce426e qemu_nbdkit: fix possible null dereference
Function virGetConnectSecret() can return NULL so we need to check it
since in virSecretGetSecretString() it gets dereferenced.

Reported-by: coverity
Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2023-09-20 14:25:17 +02:00
Jonathon Jongsma
3310b12d52 qemu: implement ssh-agent auth for ssh disks with nbdkit
It's not possible to use password-protected ssh keys directly with
libvirt because libvirt doesn't have any way to prompt a user for the
password. To accomodate password-protected key files, an administrator
can add these keys to an ssh agent and then configure the domain with
the path to the ssh-agent socket.

Note that this requires an administrator or management app to
configure the ssh-agent with an appropriate socket path and add the
necessary keys to it. In addition, it does not currently work with
selinux enabled. The ssh-agent socket would need a label that libvirt
would be allowed to access rather than unconfined_t.

Signed-off-by: Jonathon Jongsma <jjongsma@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2023-09-19 14:28:50 -05:00
Jonathon Jongsma
68599168ea qemu: implement keyfile auth for ssh disks with nbdkit
For ssh disks that are served by nbdkit, we can support logging in with
an ssh key file. Pass the path to the configured key file and the
username to the nbdkit process.

Signed-off-by: Jonathon Jongsma <jjongsma@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2023-09-19 14:28:50 -05:00
Jonathon Jongsma
21b377a31b qemu: implement knownHosts for ssh disks with nbdkit
For ssh disks that are served by nbdkit, use the configured value for
knownHosts and pass it to the nbdkit process.

Signed-off-by: Jonathon Jongsma <jjongsma@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2023-09-19 14:28:50 -05:00
Jonathon Jongsma
36f591402f qemu: implement password auth for ssh disks with nbdkit
For ssh disks that are served by nbdkit, lookup the password from the
configured secret and securely pass it to the nbdkit process using fd
passing.

Signed-off-by: Jonathon Jongsma <jjongsma@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2023-09-19 14:28:50 -05:00
Jonathon Jongsma
40935b395c qemu: try to connect to nbdkit early to detect errors
When using nbdkit to serve a network disk source, the nbdkit process
will start and wait for an nbd connection before actually attempting to
connect to the (remote) disk location. Because of this, nbdkit will not
report an error until after qemu is launched and tries to read from the
disk. This results in a fairly user-unfriendly error saying that qemu
was unable to start because "Requested export not available".

Ideally we'd like to be able to tell the user *why* the export is not
available, but this sort of information is only available to nbdkit, not
qemu. It could be because the url was incorrect, or because of an
authentication failure, or one of many other possibilities.

To make this friendlier for users and easier to detect
misconfigurations, try to connect to nbdkit immediately after starting
nbdkit and before we try to start qemu. This requires adding a
dependency on libnbd. If an error occurs when connecting to nbdkit, read
back from the nbdkit error log and provide that information in the error
report from qemuNbdkitProcessStart().

User-visible change demonstrated below:
Previous error:

    $ virsh start nbdkit-test
    2023-01-18 19:47:45.778+0000: 30895: error : virNetClientProgramDispatchError:172 : internal
    error: process exited while connecting to monitor: 2023-01-18T19:47:45.704658Z
    qemu-system-x86_64: -blockdev {"driver":"nbd","server":{"type":"unix",
    "path":"/var/lib/libvirt/qemu/domain-1-nbdkit-test/nbdkit-libvirt-1-storage.socket"},
    "node-name":"libvirt-1-storage","auto-read-only":true,"discard":"unmap"}: Requested export not
    available
    error: Failed to start domain 'nbdkit-test'
    error: internal error: process exited while connecting to monitor: 2023-01-18T19:47:45.704658Z
    qemu-system-x86_64: -blockdev {"driver":"nbd","server":{"type":"unix",
    "path":"/var/lib/libvirt/qemu/domain-1-nbdkit-test/nbdkit-libvirt-1-storage.socket"},
    "node-name":"libvirt-1-storage","auto-read-only":true,"discard":"unmap"}: Requested export not
    available

After this change:

    $ virsh start nbdkit-test
    2023-01-18 19:44:36.242+0000: 30895: error : virNetClientProgramDispatchError:172 : internal
    error: Failed to connect to nbdkit for 'http://localhost:8888/nonexistent.iso': nbdkit: curl[1]:
    error: problem doing HEAD request to fetch size of URL [http://localhost:8888/nonexistent.iso]:
    HTTP response code said error: The requested URL returned error: 404
    error: Failed to start domain 'nbdkit-test'
    error: internal error: Failed to connect to nbdkit for 'http://localhost:8888/nonexistent.iso]:
    error: problem doing HEAD request to fetch size of URL [http://localhost:8888/nonexistent.iso]:
    HTTP response code said error: The requested URL returned error: 404

Signed-off-by: Jonathon Jongsma <jjongsma@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2023-09-19 14:28:50 -05:00
Jonathon Jongsma
447e09dfdb qemu: Monitor nbdkit process for exit
Adds the ability to monitor the nbdkit process so that we can take
action in case the child exits unexpectedly.

When the nbdkit process exits, we pause the vm, restart nbdkit, and then
resume the vm. This allows the vm to continue working in the event of a
nbdkit failure.

Eventually we may want to generalize this functionality since we may
need something similar for e.g. qemu-storage-daemon, etc.

The process is monitored with the pidfd_open() syscall if it exists
(since linux 5.3). Otherwise it resorts to checking whether the process
is alive once a second. The one-second time period was chosen somewhat
arbitrarily.

Signed-off-by: Jonathon Jongsma <jjongsma@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2023-09-19 14:28:50 -05:00
Jonathon Jongsma
e7a9a2ae62 tests: add tests for nbdkit invocation
We were testing the arguments that were being passed to qemu when a disk
was being served by nbdkit, but the arguments used to start nbdkit
itself were not testable. This adds a test to ensure that we're invoking
nbdkit correctly for various disk source definitions.

Signed-off-by: Jonathon Jongsma <jjongsma@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2023-09-19 14:28:50 -05:00
Jonathon Jongsma
3361cfd79e qemu: use nbdkit to serve network disks if available
For virStorageSource objects that contain an nbdkitProcess, start that
nbdkit process to serve that network drive and then pass the nbdkit
socket to qemu rather than sending the network url to qemu directly.

Signed-off-by: Jonathon Jongsma <jjongsma@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2023-09-19 14:28:50 -05:00
Jonathon Jongsma
4f136a5f35 qemu: pass sensitive data to nbdkit via pipe
Rather than passing passwords and cookies (which could contain
passwords) to nbdkit via commandline arguments, use the alternate format
that nbdkit supports where we can specify a file descriptor which nbdkit
will read to get the password or cookies.

Signed-off-by: Jonathon Jongsma <jjongsma@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2023-09-19 14:28:50 -05:00
Jonathon Jongsma
dfa657aa27 qemu: include nbdkit state in private xml
Add xml to the private data for a disk source to represent the nbdkit
process so that the state can be re-created if the libvirt daemon is
restarted. Format:

   <nbdkit>
     <pidfile>/path/to/nbdkit.pid</pidfile>
     <socketfile>/path/to/nbdkit.socket</socketfile>
   </nbdkit>

Signed-off-by: Jonathon Jongsma <jjongsma@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2023-09-19 14:28:50 -05:00
Jonathon Jongsma
d20a6eda44 qemu: split qemuDomainSecretStorageSourcePrepare
This prepares encryption secrets and authentication secrets. When we add
nbdkit-backed network storage sources, we will not need to send
authentication secrets to qemu, since they will be sent to nbdkit
instead. So split this into two different functions.

Signed-off-by: Jonathon Jongsma <jjongsma@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2023-09-19 14:28:50 -05:00
Jonathon Jongsma
b5b1e5a947 tests: add ability to test various nbdkit capabilities
Add new DO_TEST_CAPS_LATEST_NBDKIT macro to test xml2argv for various
nbdkit capability scenarios.

Signed-off-by: Jonathon Jongsma <jjongsma@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2023-09-19 14:28:50 -05:00
Jonathon Jongsma
e04373794c qemu: log error output from nbdkit
log stderr and stdout from nbdkit into its own log so that
nbdkit-related issues can be debugged more easily.

Signed-off-by: Jonathon Jongsma <jjongsma@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2023-09-19 14:28:50 -05:00
Jonathon Jongsma
e498941476 qemu: move qemuProcessReadLog() to qemuLogContext
This code can be used by the nbdkit implementation for reading back
filtered log data for error reporting. Move it to qemuLogContext so that
it can be shared. Renamed to qemuLogContextReadFiltered().

Signed-off-by: Jonathon Jongsma <jjongsma@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2023-09-19 14:28:50 -05:00
Jonathon Jongsma
b658b1a27e qemu: Extract qemuDomainLogContext into a new file
This will allow us to use it for nbdkit logging in upcoming commits.

Signed-off-by: Jonathon Jongsma <jjongsma@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2023-09-19 14:28:50 -05:00
Jonathon Jongsma
abdc4f2092 Generalize qemuDomainLogContextNew()
Allow to specify a basename for the log file so that
qemuDomainLogContextNew() can be used to create log contexts for
secondary loggers.

Signed-off-by: Jonathon Jongsma <jjongsma@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2023-09-19 14:28:50 -05:00
Jonathon Jongsma
8d73929e04 qemu: add functions to start and stop nbdkit
Add some helper functions to build a virCommand object and run the
nbdkit process for a given virStorageSource.

Signed-off-by: Jonathon Jongsma <jjongsma@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2023-09-19 14:28:50 -05:00
Jonathon Jongsma
4a632de2ac qemu: query nbdkit module dir from binary
Rather than hard-coding the nbdkit module directory, query the nbdkit
binary for the location to these directories. nbdkit provides a
--dump-config optiont that outputs this information and can be easily
parsed. We can also get the version from this output rather than
executing `nbdkit --version` separately.

Signed-off-by: Jonathon Jongsma <jjongsma@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2023-09-19 14:28:50 -05:00
Jonathon Jongsma
1475c8c0d7 qemu: Add qemuNbdkitProcess
An object for storing information about a nbdkit process that is serving
a specific virStorageSource. At the moment, this information is just
stored in the private data of virStorageSource and not used at all.
Future commits will use this data to actually start a nbdkit process.

Signed-off-by: Jonathon Jongsma <jjongsma@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2023-09-19 14:28:50 -05:00
Jonathon Jongsma
0c00059a72 qemu: use file cache for nbdkit caps
Add the virFileCache implementation for nbdkit capabilities to the qemu
driver. This allows us to determine whether nbdkit is installed and
which plugins are supported. it also has persistent caching and the
capabilities are re-queried whenever something changes.

Signed-off-by: Jonathon Jongsma <jjongsma@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2023-09-19 14:28:50 -05:00
Jonathon Jongsma
d0fd04556c qemu: implement persistent file cache for nbdkit caps
Implement the loadFile and saveFile virFileCacheHandlers callbacks so
that nbdkit capabilities are cached perstistently across daemon
restarts. The format and implementation is modeled on the qemu
capabilities, but simplified slightly.

Signed-off-by: Jonathon Jongsma <jjongsma@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2023-09-19 14:28:50 -05:00
Jonathon Jongsma
9c0b83a9ed qemu: implement basic virFileCache for nbdkit caps
Preparatory step for caching nbdkit capabilities. This patch implements
the newData and isValid virFileCacheHandlers callback functions.

Signed-off-by: Jonathon Jongsma <jjongsma@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2023-09-19 14:28:49 -05:00
Jonathon Jongsma
03afd10cd3 qemu: expand nbdkit capabilities
In order to add caching of the nbdkit capabilities, we will need to
compare against file modification times, etc. So look up this
information when creating the nbdkit caps.

Add a nbdkit_moddir build option to allow the builder to specify the
location to look for nbdkit plugins and filters.

Signed-off-by: Jonathon Jongsma <jjongsma@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2023-09-19 14:28:49 -05:00
Jonathon Jongsma
6b7e6b73a9 qemu: Add functions for determining nbdkit availability
In future commits, we will optionally use nbdkit to serve some remote
disk sources. This patch queries to see whether nbdkit is installed on
the host and queries it for capabilities. The data will be used in later
commits.

Signed-off-by: Jonathon Jongsma <jjongsma@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2023-09-19 14:28:49 -05:00
Michal Privoznik
732c5f4270 src: Avoid needless checks before calling g_strdup()
There are few places where the following pattern occurs:

  if (var)
      other = g_strdup(var);

where @other wasn't initialized before g_strdup(). Checking for
var != NULL is useless in this case, as that's exactly what
g_strdup() does (in which case it returns NULL).

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2023-09-18 14:46:24 +02:00
Michal Privoznik
452695926d virStorageNetHostDef: Convert 'transport' field to proper enum type
Convert the field and adjust the XML parsers to use
virXMLPropEnumDefault().

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2023-09-15 10:35:20 +02:00
Michal Privoznik
2dd6369477 virDomainDeviceInfo: Convert 'type' field to proper enum type
Convert the field, adjust the XML parsers to use virXMLPropEnum()
and fill in missing cases to switch() statements.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2023-09-15 10:35:17 +02:00
Michal Privoznik
a6eadf00d2 virDomainWatchdogDef: Convert 'model' field to proper enum type
Convert the field and adjust the XML parsers to use
virXMLPropEnum().

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2023-09-15 10:35:13 +02:00
Michal Privoznik
b691d249d1 virDomainRNGDef: Convert 'backend' field to proper enum type
Convert the field and adjust the XML parser to use
virXMLPropEnum().

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2023-09-15 10:35:11 +02:00
Michal Privoznik
53edfa23f1 virDomainRNGDef: Convert 'model' field to proper enum type
Convert the field and adjust the XML parser to use
virXMLPropEnum().

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2023-09-15 10:35:09 +02:00
Michal Privoznik
27a653b893 virDomainControllerDef: Convert 'type' field to proper enum type
Convert the field and fill in missing cases to switch()
statements.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2023-09-15 10:35:06 +02:00
Michal Privoznik
44f0371c8c virDomainHostdevSubsys: Convert 'type' field to proper enum type
Convert the field, and fill in missing cases to switch()
statements.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2023-09-15 10:35:04 +02:00
Michal Privoznik
7bdab79e40 virDomainHostdevDef: Convert 'mode' field to proper enum type
Convert the field, adjust the XML parser to use
virXMLPropEnumDefault() and fill in missing cases to switch()
statements.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2023-09-15 10:34:59 +02:00
Michal Privoznik
d537f203b9 virDomainHostdevSubsysSCSI: Convert 'protocol' field to proper enum type
Convert the field and adjust the XML parser to use
virXMLPropEnum().

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2023-09-15 10:34:54 +02:00
Michal Privoznik
f7534c2573 src: Drop needless typecast to virDomainDiskBus
The 'bus' member of _virDomainDiskDef is already declared of
virDomainDiskModel type. Hence, there is no need to typecast the
variable when passing to switch() statements.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2023-09-15 10:34:52 +02:00
Michal Privoznik
0041723233 qemu_domain_address: Drop needless typecast to virDomainDiskModel
The 'mode' member of _virDomainDiskDef is already declared of
virDomainDiskModel type. Hence, there is no need to typecast the
variable when passing to switch() statements.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2023-09-15 10:34:50 +02:00
Michal Privoznik
75cdb664d0 src: Drop needless typecast to virDomainDeviceType
The 'type' member of _virDomainDeviceDef is already declared of
virDomainDeviceType type. Hence, there is no need to typecast the
variable when passing to switch() statements.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2023-09-15 10:34:48 +02:00
Michal Privoznik
3926f1e688 qemu: Drop needless typecast to virDomainFSDriverType
The 'fsdriver' member of _virDomainFSDef is already declared of
virDomainFSDriverType type. Hence, there is no need to typecast
the variable when passing to switch() statements.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2023-09-15 10:34:44 +02:00
Michal Privoznik
8435be3923 qemu_domain_address: Drop needless typecast in qemuDomainDeviceCalculatePCIConnectFlags()
Inside of qemuDomainDeviceCalculatePCIConnectFlags() there's a
switch() which typecasts a variable of
virDomainHostdevSubsysSCSIVHostModelType type to the very same
type. This is useless.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2023-09-15 10:34:41 +02:00
Jonathon Jongsma
4ef2bcfd3f qemu: Implement support for vDPA block devices
Requires recent qemu with support for the virtio-blk-vhost-vdpa device
and the ability to pass a /dev/fdset/N path for the vdpa path (8.1.0)

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1900770
Signed-off-by: Jonathon Jongsma <jjongsma@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2023-09-12 11:06:41 -05:00
Jonathon Jongsma
2efa9ba66a qemu: consider vdpa block devices for memlock limits
vDPA block devices will also need the same consideration for memlock
limits as other vdpa devices, so consider these devices when calculating
memlock limits.

Signed-off-by: Jonathon Jongsma <jjongsma@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2023-09-12 11:06:41 -05:00
Jonathon Jongsma
0ebb416d7e qemu: make vdpa connect function more generic
qemuInterfaceVDPAConnect() was a helper function for connecting to the
vdpa device file. But in order to support other vdpa devices besides
network interfaces (e.g. vdpa block devices) make this function a bit
more generic.

Signed-off-by: Jonathon Jongsma <jjongsma@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2023-09-12 11:06:41 -05:00
Jonathon Jongsma
6cf7dbeff8 qemu: add virtio-blk-vhost-vdpa capability
Check whether the qemu binary supports the vdpa block driver. We can't
rely simply on the existence of the virtio-blk-vhost-vdpa block driver
since the first releases of qemu didn't support fd-passing for this
driver. So we have to check for the 'fdset' feature on the driver
object. This feature will be present in the qemu 8.1.0 release and was
merged to qemu in commit 98b126f5.

Signed-off-by: Jonathon Jongsma <jjongsma@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2023-09-12 11:06:41 -05:00
Jonathon Jongsma
1df106cc20 conf: add ability to configure a vdpa block disk device
vDPA block devices can be configured as follows:

    <disk type='vhostvdpa'>
      <source dev='/dev/vhost-vdpa-0'/>
    </disk>

Signed-off-by: Jonathon Jongsma <jjongsma@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2023-09-12 11:06:41 -05:00