If xenstored runs out of memory it is possible for it to fail operations
that should succeed. libxl wasn't robust against this, and could fail
to ensure that the TTY path of a non-initial console was created and
read-only for guests. This doesn't qualify for an XSA because guests
should not be able to run xenstored out of memory, but it still needs to
be fixed.
Add the missing error checks to ensure that all errors are properly
handled and that at no point can a guest make the TTY path of its
frontend directory writable.
Signed-off-by: Demi Marie Obenour <demi@invisiblethingslab.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Add support for xl devd to support 9pfs in a domU. devd need to spawn a
pvqemu for the domain to service 9pfs as well as qdisk backends. Rename
num_qdisks to pvqemu_refcnt to be more generic.
Keep the qdisk-backend-pid xenstore key as well as the disk-%u log file.
They are externally visible, so they might be used by other tooling.
Signed-off-by: Jason Andryuk <jandryuk@gmail.com>
Signed-off-by: Jason Andryuk <jason.andryuk@amd.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>
Print the rc when an error is found in device_backend_callback() so the
user can have some idea of why things went wrong.
Signed-off-by: Jason Andryuk <jandryuk@gmail.com>
Reviewed-by: Juergen Gross <jgross@suse.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>
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>
When device is removed, backend domain (which may be a driver domain) is
responsible for removing backend entries from xenstore. But in case of
driver domain, it has no access to remove all of them - specifically the
directory named after frontend-id remains. This may accumulate enough to
exceed xenstore quote of the driver domain, breaking further devices.
Fix this by calling libxl__xs_path_cleanup() on the backend path from
libxl__device_destroy() in the toolstack domain too. Note
libxl__device_destroy() is called when the driver domain already removed
what it can (see device_destroy_be_watch_cb()->device_hotplug_done()).
Signed-off-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Acked-by: Wei Liu <wl@xen.org>
... devices.
Currently there is an assumption built into libxl__device_list() that device
backends are fully enumarated under the '/libxl' path in xenstore. This is
not the case for PCI backend devices, which are only properly enumerated
under '/local/domain/0/backend'.
This patch adds a new get_path() method to libxl__device_type to allow a
backend implementation (such as PCI) to specify the xenstore path where
devices are enumerated and modifies libxl__device_list() to use this method
if it is available. Also, if the get_num() method is defined then the
from_xenstore() method expects to be passed the backend path without the device
number concatenated, so this issue is also rectified.
Having made libxl__device_list() work correctly, this patch removes the
open-coded libxl_pci_device_pci_list() in favour of an evaluation of the
LIBXL_DEFINE_DEVICE_LIST() macro. This has the side-effect of also defining
libxl_pci_device_pci_list_free() which will be used in subsequent patches.
Signed-off-by: Paul Durrant <pdurrant@amazon.com>
Reviewed-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.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>
Demi Marie Obenour
Jason Andryuk
Oleksandr Tyshchenko
Juergen Gross
Marek Marczykowski-Górecki
Paul Durrant