This patch adds create and destroy function for XenBlockDevice-s so that
they can be created automatically when the Xen toolstack instantiates a new
PV backend via xenstore. When the XenBlockDevice is created this way it is
also necessary to create a 'drive' which matches the configuration that the
Xen toolstack has written into xenstore. This is done by formulating the
parameters necessary for each 'blockdev' layer of the drive and then using
qmp_blockdev_add() to create the layers. Also, for compatibility with the
legacy 'xen_disk' implementation, an iothread is automatically created for
the new XenBlockDevice. This, like the driver layers, will be destroyed
after the XenBlockDevice is unrealized.
The legacy backend scan for 'qdisk' is removed by this patch, which makes
the 'xen_disk' code is redundant. The code will be removed by a subsequent
patch.
Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
Reviewed-by: Anthony PERARD <anthony.perard@citrix.com>
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
...and wire in the dataplane.
This patch adds the remaining code to make the xen-block XenDevice
functional. The parameters that a block frontend expects to find are
populated in the backend xenstore area, and the 'ring-ref' and
'event-channel' values specified in the frontend xenstore area are
mapped/bound and used to set up the dataplane.
Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
Reviewed-by: Anthony Perard <anthony.perard@citrix.com>
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
This patch adds new XenDevice-s: 'xen-disk' and 'xen-cdrom', both derived
from a common 'xen-block' parent type. These will eventually replace the
'xen_disk' (note the underscore rather than hyphen) legacy PV backend but
it is illustrative to build up the implementation incrementally, along with
the XenBus/XenDevice framework. Subsequent patches will therefore add to
these devices' implementation as new features are added to the framework.
After this patch has been applied it is possible to instantiate new
'xen-disk' or 'xen-cdrom' devices with a single 'vdev' parameter, which
accepts values adhering to the Xen VBD naming scheme [1]. For example, a
command-line instantiation of a xen-disk can be done with an argument
similar to the following:
-device xen-disk,vdev=hda
The implementation of the vdev parameter formulates the appropriate VBD
number for use in the PV protocol.
[1] https://xenbits.xen.org/docs/unstable/man/xen-vbd-interface.7.html
Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
Reviewed-by: Anthony Perard <anthony.perard@citrix.com>
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
