Hard drives, floppy disks, CDROMs¶

Disk capabilities are exposed under the disk element. For instance:

<domainCapabilities>
  ...
  <devices>
    <disk supported='yes'>
      <enum name='diskDevice'>
        <value>disk</value>
        <value>cdrom</value>
        <value>floppy</value>
        <value>lun</value>
      </enum>
      <enum name='bus'>
        <value>ide</value>
        <value>fdc</value>
        <value>scsi</value>
        <value>virtio</value>
        <value>xen</value>
        <value>usb</value>
        <value>sata</value>
        <value>sd</value>
      </enum>
    </disk>
    ...
  </devices>
</domainCapabilities>

diskDevice

Options for the device attribute of the <disk/> element.

bus

Options for the bus attribute of the <target/> element for a <disk/>.

Graphical framebuffers¶

Graphics device capabilities are exposed under the graphics element. For instance:

<domainCapabilities>
  ...
  <devices>
    <graphics supported='yes'>
      <enum name='type'>
        <value>sdl</value>
        <value>vnc</value>
        <value>spice</value>
      </enum>
    </graphics>
    ...
  </devices>
</domainCapabilities>

type

Options for the type attribute of the <graphics/> element.

Video device¶

Video device capabilities are exposed under the video element. For instance:

<domainCapabilities>
  ...
  <devices>
    <video supported='yes'>
      <enum name='modelType'>
        <value>vga</value>
        <value>cirrus</value>
        <value>vmvga</value>
        <value>qxl</value>
        <value>virtio</value>
      </enum>
    </video>
    ...
  </devices>
</domainCapabilities>

modelType

Options for the type attribute of the <video><model> element.

Host device assignment¶

Some host devices can be passed through to a guest (e.g. USB, PCI and SCSI). Well, only if the following is enabled:

<domainCapabilities>
  ...
  <devices>
    <hostdev supported='yes'>
      <enum name='mode'>
        <value>subsystem</value>
        <value>capabilities</value>
      </enum>
      <enum name='startupPolicy'>
        <value>default</value>
        <value>mandatory</value>
        <value>requisite</value>
        <value>optional</value>
      </enum>
      <enum name='subsysType'>
        <value>usb</value>
        <value>pci</value>
        <value>scsi</value>
      </enum>
      <enum name='capsType'>
        <value>storage</value>
        <value>misc</value>
        <value>net</value>
      </enum>
      <enum name='pciBackend'>
        <value>default</value>
        <value>kvm</value>
        <value>vfio</value>
        <value>xen</value>
      </enum>
    </hostdev>
  </devices>
</domainCapabilities>

mode

Options for the mode attribute of the <hostdev/> element.

startupPolicy

Options for the startupPolicy attribute of the <hostdev/> element.

subsysType

Options for the type attribute of the <hostdev/> element in case of mode="subsystem".

capsType

Options for the type attribute of the <hostdev/> element in case of mode="capabilities".

pciBackend

Options for the name attribute of the <driver/> element.

RNG device¶

RNG device capabilities are exposed under the rng element. For instance:

<domainCapabilities>
  ...
  <devices>
    <rng supported='yes'>
      <enum name='model'>
        <value>virtio</value>
        <value>virtio-transitional</value>
        <value>virtio-non-transitional</value>
      </enum>
      <enum name='backendModel'>
        <value>random</value>
        <value>egd</value>
        <value>builtin</value>
      </enum>
    </rng>
    ...
  </devices>
</domainCapabilities>

model

Options for the model attribute of the <rng> element.

backendModel

Options for the model attribute of the <rng><backend> element.

Filesystem device¶

Filesystem device capabilities are exposed under the filesystem element. For instance:

<domainCapabilities>
  ...
  <devices>
    <filesystem supported='yes'>
      <enum name='driverType'>
        <value>default</value>
        <value>path</value>
        <value>handle</value>
        <value>virtiofs</value>
      </enum>
    </filesystem>
    ...
  </devices>
</domainCapabilities>

driverType

Options for the type attribute of the <filesystem><driver> element.

TPM device¶

TPM device capabilities are exposed under the tpm element. For instance:

<domainCapabilities>
  ...
  <devices>
    <tpm supported='yes'>
      <enum name='model'>
        <value>tpm-tis</value>
        <value>tpm-crb</value>
      </enum>
      <enum name='backendModel'>
        <value>passthrough</value>
        <value>emulator</value>
      </enum>
      <enum name='backendVersion'>
        <value>1.2</value>
        <value>2.0</value>
      </enum>
    </tpm>
    ...
  </devices>
</domainCapabilities>

model

Options for the model attribute of the <tpm/> element.

backendModel

Options for the type attribute of the <tpm><backend/> element.

backendVersion

Options for the version attribute of the <tpm><backend/> element.

USB redirect device¶

USB redirdev device capabilities are exposed under the redirdev element. For instance:

<domainCapabilities>
  ...
  <devices>
    <redirdev supported='yes'>
      <enum name='bus'>
        <value>usb</value>
      </enum>
    </redirdev>
    ...
  </devices>
</domainCapabilities>

bus

Options for the bus attribute of the <redirdev/> element.

Channel device¶

Channel device capabilities are exposed under the channel element. For instance:

<domainCapabilities>
  ...
  <devices>
    <channel supported='yes'>
      <enum name='type'>
        <value>pty</value>
        <value>unix</value>
        <value>spicevmc</value>
      </enum>
    </channel
    ...
  </devices>
</domainCapabilities>

type

Options for the type attribute of the <channel/> element.

Crypto device¶

Crypto device capabilities are exposed under the crypto element. For instance:

<domainCapabilities>
  ...
  <devices>
    <crypto supported='yes'>
      <enum name='model'>
        <value>virtio</value>
      </enum>
      <enum name='type'>
        <value>qemu</value>
      </enum>
      <enum name='backendModel'>
        <value>builtin</value>
        <value>lkcf</value>
      </enum>
    </crypto>
    ...
  </devices>
</domainCapabilities>

model

Options for the model attribute of the <crypto/> element.

type

Options for the type attribute of the <crypto/> element.

backendModel

Options for the backendModel attribute of the <crypto><backend/> element.

GIC capabilities¶

GIC capabilities are exposed under the gic element.

version

Options for the version attribute of the gic element.

vmcoreinfo¶

Reports whether the vmcoreinfo feature can be enabled.

genid¶

Reports whether the genid feature can be used by the domain.

backingStoreInput¶

Reports whether the hypervisor will obey the <backingStore> elements configured for a <disk> when booting the guest, hotplugging the disk to a running guest, or similar. (Since 5.10)

backup¶

Reports whether the hypervisor supports the backup, checkpoint, and related features. (virDomainBackupBegin, virDomainCheckpointCreateXML etc). The presence of the backup element even if supported='no' implies that the VIR_DOMAIN_UNDEFINE_CHECKPOINTS_METADATA flag for virDomainUndefine is supported.

async-teardown¶

Reports whether the asynchronous teardown feature can be enabled.

s390-pv capability¶

Reports whether the hypervisor supports the Protected Virtualization. In order to use Protected Virtualization with libvirt have a look at the launchSecurity element in the domain XML. For more details on the Protected Virtualization feature please see Protected Virtualization on s390.

SEV capabilities¶

AMD Secure Encrypted Virtualization (SEV) capabilities are exposed under the sev element. SEV is an extension to the AMD-V architecture which supports running virtual machines (VMs) under the control of a hypervisor. When supported, guest owner can create a VM whose memory contents will be transparently encrypted with a key unique to that VM.

For more details on the SEV feature, please follow resources in the AMD developer's document store. In order to use SEV with libvirt have a look at SEV in domain XML

cbitpos

When memory encryption is enabled, one of the physical address bits (aka the C-bit) is utilized to mark if a memory page is protected. The C-bit position is Hypervisor dependent.

reducedPhysBits

When memory encryption is enabled, we lose certain bits in physical address space. The number of bits we lose is hypervisor dependent.

maxGuests

The maximum number of SEV guests that can be launched on the host. This value may be configurable in the firmware for some hosts.

maxESGuests

The maximum number of SEV-ES guests that can be launched on the host. This value may be configurable in the firmware for some hosts.

SGX capabilities¶

Intel Software Guard Extensions (Intel SGX) capabilities are exposed under the sgx element.

Intel SGX helps protect data in use via unique application isolation technology. Protect selected code and data from modification using hardened enclaves with Intel SGX.

For more details on the SGX feature, please follow resources in the SGX developer's document store. In order to use SGX with libvirt have a look at SGX in domain XML

flc

FLC (Flexible Launch Control), not strictly part of SGX2, but was not part of original SGX hardware either.

sgx1

the sgx version 1.

sgx2

The sgx version 2.

section_size

The size of the SGX enclave page cache (called EPC).

sections

The sections of the SGX enclave page cache (called EPC).

Hyper-V Enlightenments¶

Report which features improving behavior of guests running Microsoft Windows are supported. The features enum corresponds to the <hyperv/> element (well, its children) as documented in Hypervisor features.

Please note that depending on the QEMU version some capabilities might be missing even though QEMU does support them. This is because prior to QEMU-6.1.0 not all features were reported by QEMU.