[libvirt PATCH 1/2] docs: update description of virsh nodedev-detach --driver option

[Laine Stump]

--driver can now be used to specify a specific driver to bind to the
device being detached from the host driver (e.g. vfio-pci-igbvf), not
just the *type* of driver (e.g. "vfio" or "xen", which are unnecessary
anyway, since they are implicit in which hypervisor driver is in use)

Signed-off-by: Laine Stump <laine at redhat.com>
---
 docs/manpages/virsh.rst | 25 +++++++++++++++++--------
 1 file changed, 17 insertions(+), 8 deletions(-)

diff --git a/docs/manpages/virsh.rst b/docs/manpages/virsh.rst
index f4e5a0bd62..ec7c823602 100644
--- a/docs/manpages/virsh.rst
+++ b/docs/manpages/virsh.rst
@@ -5388,14 +5388,23 @@ nodedev-detach
 
    nodedev-detach nodedev [--driver backend_driver]
 
-Detach *nodedev* from the host, so that it can safely be used by
-guests via <hostdev> passthrough.  This is reversed with
-``nodedev-reattach``, and is done automatically for managed devices.
-
-Different backend drivers expect the device to be bound to different
-dummy devices. For example, QEMU's "vfio" backend driver expects the
-device to be bound to vfio-pci. The *--driver* parameter can be used
-to specify the desired backend driver.
+Detach *nodedev* from the host driver and bind it to a special driver
+that provides the API needed by the hypervisor for assigning the
+device to a virtual machine (using <hostdev> in the domain XML
+definition).  This is reversed with ``nodedev-reattach``, and is done
+automatically by the hypervisor driver for managed devices (those
+devices with "managed='yes'" in their XML definition).
+
+Different hypervisors expect the device being assigned to be bound to
+different drivers. For example, QEMU's "vfio" backend requires the
+device to be bound to the driver "vfio-pci" or to a "VFIO variant"
+driver (this is a driver that supports the full API provided by
+vfio-pci, plus some other APIs to support things like live
+migration). The *--driver* parameter can be used to specify a
+particular driver (e.g. a device-specific VFIO variant driver) the
+device should be bound to. When *--driver* is omitted, the default
+driver for the hypervisor is used ("vfio-pci" for QEMU, "pciback" for
+Xen).
 
 
 nodedev-dumpxml
-- 
2.41.0