Allow administrators to control whether Xen grant mappings for
the virtio disk devices should be used. By default (when new
parameter is not specified), the existing behavior is retained
(we enable grants if backend-domid != 0).
Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Reviewed-by: Anthony PERARD <anthony.perard@citrix.com>
A Linux HVM domain ignores PV block devices with type cdrom. The
Windows PV drivers also ignore device-type != "disk". Therefore QEMU's
emulated CD-ROM support is used. This allows ejection and other CD-ROM
features to work.
With a stubdom, QEMU is running in the stubdom. A PV disk is still
connected into the stubdom, and then QEMU can emulate the CD-ROM into
the guest. Phy support has been enhanced to provide a placeholder file
forempty disks, so it is usable as a CDROM backend as well. Allow Phy
to pass the check as well.
(Bypassing just for a linux-based stubdom doesn't work because
libxl__device_disk_setdefault() gets called early in domain creation
before xenstore is populated with relevant information for the stubdom
type. The build information isn't readily available and won't exist in
some call trees, so it isn't usable either.)
Let disk_try_backend() allow format empty for Phy cdrom drives.
Signed-off-by: Jason Andryuk <jandryuk@gmail.com>
Reviewed-by: Anthony PERARD <anthony.perard@citrix.com>
With a device model stubdom, dom0 exports a PV disk to the stubdom.
Inside the stubdom, QEMU emulates a cdrom to the guest with a
host_device pointing at the PV frontend (/dev/xvdc)
An empty cdrom drive causes problems booting the stubdom. The PV disk
protocol isn't designed to support no media. That can be partially
hacked around, but the stubdom kernel waits for all block devices to
transition to Connected. Since the backend never connects empty media,
stubdom launch times out and it is destroyed.
Empty media and the PV disks not connecting is fine at runtime since the
stubdom keeps running irrespective of the disk state.
Empty media can be worked around my providing an empty file to the
stubdom for the PV disk source. This works as the disk is exposed as a
zero-size disk. Dynamically create the empty file as needed and remove
in the stubdom cleanup.
libxl__device_disk_set_backend() needs to allow through these "empty"
disks with a pdev_path.
Fixup the params writing since scripts have trouble with an empty params
field.
This works for non-stubdom HVMs as well.
Signed-off-by: Jason Andryuk <jandryuk@gmail.com>
Reviewed-by: Anthony PERARD <anthony.perard@citrix.com>
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>
This patch adds basic support for configuring and assisting virtio-mmio
based virtio-disk backend (emulator) which is intended to run out of
Qemu and could be run in any domain.
Although the Virtio block device is quite different from traditional
Xen PV block device (vbd) from the toolstack's point of view:
- as the frontend is virtio-blk which is not a Xenbus driver, nothing
written to Xenstore are fetched by the frontend currently ("vdev"
is not passed to the frontend). But this might need to be revised
in future, so frontend data might be written to Xenstore in order to
support hotplugging virtio devices or passing the backend domain id
on arch where the device-tree is not available.
- the ring-ref/event-channel are not used for the backend<->frontend
communication, the proposed IPC for Virtio is IOREQ/DM
it is still a "block device" and ought to be integrated in existing
"disk" handling. So, re-use (and adapt) "disk" parsing/configuration
logic to deal with Virtio devices as well.
For the immediate purpose and an ability to extend that support for
other use-cases in future (Qemu, virtio-pci, etc) perform the following
actions:
- Add new disk backend type (LIBXL_DISK_BACKEND_STANDALONE) and reflect
that in the configuration
- Introduce new disk "specification" and "transport" fields to struct
libxl_device_disk. Both are written to the Xenstore. The transport
field is only used for the specification "virtio" and it assumes
only "mmio" value for now.
- Introduce new "specification" option with "xen" communication
protocol being default value.
- Add new device kind (LIBXL__DEVICE_KIND_VIRTIO_DISK) as current
one (LIBXL__DEVICE_KIND_VBD) doesn't fit into Virtio disk model
An example of domain configuration for Virtio disk:
disk = [ 'phy:/dev/mmcblk0p3, xvda1, backendtype=standalone, specification=virtio']
Nothing has changed for default Xen disk configuration.
Please note, this patch is not enough for virtio-disk to work
on Xen (Arm), as for every Virtio device (including disk) we need
to allocate Virtio MMIO params (IRQ and memory region) and pass
them to the backend, also update Guest device-tree. The subsequent
patch will add these missing bits. For the current patch,
the default "irq" and "base" are just written to the Xenstore.
This is not an ideal splitting, but this way we avoid breaking
the bisectability.
Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Reviewed-by: Anthony PERARD <anthony.perard@citrix.com>
Acked-by: George Dunlap <george.dunlap@citrix.com>
Tested-by: Jiamei Xie <jiamei.xie@arm.com>
Allow administrators to notify a frontend driver that it's backend
counterpart is not to be trusted, so the frontend can deploy whatever
mitigations required in order to secure itself.
Allow such option for disk and network frontends only, as those are
the only hardened ones currently supported.
This is part of XSA-403
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Anthony PERARD <anthony.perard@citrix.com>
Remove generating _libxl_list.h and use the common _xen_list.h instead.
Signed-off-by: Juergen Gross <jgross@suse.com>
Acked-by: Anthony PERARD <anthony.perard@citrix.com>
"change" command as been removed in QEMU 6.0. We can use
"blockdev-change-medium" instead.
Using `id` with "blockdev-change-medium" requires a change to the QEMU
command line, introduced by:
"libxl: Use -device for cd-rom drives"
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Reviewed-by: Jason Andryuk <jandryuk@gmail.com>
`device` parameter is deprecated since QEMU 2.8.
This requires changes to the command line introduced by:
"libxl: Use -device for cd-rom drives"
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Reviewed-by: Jason Andryuk <jandryuk@gmail.com>
The seemingly arbitrary use of 'pci' and 'pcidev' in the code in libxl_pci.c
is confusing and also compromises use of some macros used for other device
types. Indeed it seems that DEFINE_DEVICE_TYPE_STRUCT_X exists solely because
of this duality.
This patch purges use of 'pcidev' from the libxl internal code, but
unfortunately the 'pcidevs' and 'num_pcidevs' fields in 'libxl_domain_config'
are part of the API and need to be retained to avoid breaking callers,
particularly libvirt.
DEFINE_DEVICE_TYPE_STRUCT_X is still removed to avoid the special case in
libxl_pci.c but DEFINE_DEVICE_TYPE_STRUCT is given an extra 'array' argument
which is used to identify the fields in 'libxl_domain_config' relating to
the device type.
NOTE: Some of the more gross formatting errors (such as lack of spaces after
keywords) that came into context have been fixed in libxl_pci.c.
Signed-off-by: Paul Durrant <pdurrant@amazon.com>
Acked-by: Wei Liu <wl@xen.org>
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
Oleksandr Tyshchenko
Roger Pau Monne
Juergen Gross
Anthony PERARD
Paul Durrant