device assignment. Use the <code>name</code> attribute to
select either "vfio" (for the new VFIO device assignment
backend, which is compatible with UEFI SecureBoot) or "kvm"
- (for the legacy device assignment handled directly by the KVM
+ (the legacy device assignment handled directly by the KVM
kernel module)<span class="since">Since 1.0.5 (QEMU and KVM
- only, requires kernel 3.6 or newer)</span>. The default, when
- the driver name is not explicitly specified, is to check whether
- VFIO is available and use it if it's the case. If VFIO is not
- available, the legacy "kvm" assignment is attempted.
+ only, requires kernel 3.6 or newer)</span>. When specified,
+ device assignment will fail if the requested method of device
+ assignment isn't available on the host. When not specified,
+ the default is "vfio" on systems where the VFIO driver is
+ available and loaded, and "kvm" on older systems, or those
+ where the VFIO driver hasn't been
+ loaded <span class="since">Since 1.1.3</span> (prior to that
+ the default was always "kvm").
</dd>
<dt><code>readonly</code></dt>
<dd>Indicates that the device is readonly, only supported by SCSI host
definition. <span class="since"> Since 0.10.0</span>
<p>
- To use VFIO device assignment rather than
- traditional/legacy KVM device assignment (VFIO is a new
- method of device assignment that is compatible with UEFI
- Secure Boot), a <forward type='hostdev'> interface
- can have an optional <code>driver</code> sub-element
- with a <code>name</code> attribute set to "vfio". To use
- legacy KVM device assignment you can
- set <code>name</code> to "kvm" (or simply omit the
- <driver> element, since "kvm" is currently the
- default).
- <span class="since">Since 1.0.5 (QEMU and KVM only, requires kernel 3.6 or newer)</span>
+ To force use of a particular type of device assignment,
+ a <forward type='hostdev'> interface can have an
+ optional <code>driver</code> sub-element with
+ a <code>name</code> attribute set to either "vfio" (VFIO
+ is a new method of device assignment that is compatible
+ with UEFI Secure Boot) or "kvm" (the legacy device
+ assignment handled directly by the KVM kernel module)
+ <span class="since">Since 1.0.5 (QEMU and KVM only,
+ requires kernel 3.6 or newer)</span>. When specified,
+ device assignment will fail if the requested method of
+ device assignment isn't available on the host. When not
+ specified, the default is "vfio" on systems where the
+ VFIO driver is available and loaded, and "kvm" on older
+ systems, or those where the VFIO driver hasn't been
+ loaded <span class="since">Since 1.1.3</span> (prior to
+ that the default was always "kvm").
</p>
<p>Note that this "intelligent passthrough" of network