This patch re-introduces blktap support to libxl. Unlike earlier
versions, it does not link against any blktap library. libxl changes
are needed to write to the vbd3 backend XenStore nodes.
blktap has three components. tapdisk is a daemon implementing the disk
IO, NBD (Network Block Device), and Xen PV interfaces. tap-ctl is a
tool to control tapdisks - creating, starting, stopping and freeing.
tapback manages the XenStore operations and instructs tapdisk to
connect.
It is notable that tapdisk performs the grant and event channel ops, but
doesn't interact with XenStore. tapback performs XenStore operations
and notifies tapdisks of values and changes.
The flow is: libxl writes to the "vbd3" XenStore nodes and runs the
block-tap script. The block-tap script runs tap-ctl to create a tapdisk
instance as the physical device. tapback then sees the tapdisk and
instructs the tapdisk to connect up the PV blkif interface.
This is expected to work without the kernel blktap driver, so the
block-tap script is modified accordingly to write the UNIX NBD path.
backendtype=tap was not fully removed previously, but it would never
succeed since it would hit the hardcoded error in disk_try_backend().
It is reused now.
An example command to attach a vhd:
xl block-attach vm 'vdev=xvdf,backendtype=tap,format=vhd,target=/srv/target.vhd'
Format raw also works to run an "aio:" tapdisk.
Signed-off-by: Jason Andryuk <jandryuk@gmail.com>
Reviewed-by: Anthony PERARD <anthony.perard@citrix.com>
Printing the integer isn't particularly informative. Switch to a
human-readable string when printing the device_kind in
libxl__get_hotplug_script_info().
Signed-off-by: Jason Andryuk <jandryuk@gmail.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Setting errno to a negative value makes no sense.
Fixes: e78e8b9bb6 ("libxl: Add interface for querying hypervisor about PCI topology")
Signed-off-by: Juergen Gross <jgross@suse.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
Switch NetBSD to QEMU_XEN.
All 3 versions of libxl__default_device_model() now return
LIBXL_DEVICE_MODEL_VERSION_QEMU_XEN, so remove it and just set
b_info->device_model_version to LIBXL_DEVICE_MODEL_VERSION_QEMU_XEN in
libxl__domain_build_info_setdefault().
Signed-off-by: Manuel Bouyer <bouyer@netbsd.org>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
Carve out all libxenlight related sources and move them to
tools/libs/light in order to use the generic library build environment.
The closely related sources for libxl-save-helper and the libxl test
environment are being moved, too.
Signed-off-by: Juergen Gross <jgross@suse.com>
Acked-by: Wei Liu <wl@xen.org>
Jason Andryuk
Juergen Gross
Manuel Bouyer