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2019-02-28xen-block: stop leaking memory in xen_block_drive_create()Paul Durrant
The locally allocated QDict-s need to be freed. ('file_layer' will be freed implicitly since it is added as an object to 'driver_layer'). Spotted by Coverity: CID 1398649 While in the neighbourhood free 'driver' and 'filename' as soon as they are added to the QDicts. Freeing after the 'done' label doesn't make that much sense as, if the error path jumps to that label, the values would be NULL anyway. This patch also makes that more obvious by taking the error path if 'params' is NULL and then asserting that both driver and filename are non-NULL in the normal path. Reported-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Paul Durrant <paul.durrant@citrix.com> Message-Id: <20190219163440.15702-1-paul.durrant@citrix.com> Acked-by: Anthony PERARD <anthony.perard@citrix.com> Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
2019-02-28xen-block: report error condition from vbd_name_to_disk()Paul Durrant
The function needs to make sure it is passed a valid disk name. This is easily done by making sure that the parsing loop results in a non-zero value. Spotted by Coverity: CID 1398640 Reported-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Paul Durrant <paul.durrant@citrix.com> Acked-by: Anthony PERARD <anthony.perard@citrix.com> Message-Id: <20190215162533.19475-4-paul.durrant@citrix.com> Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
2019-02-28xen-block: remove redundant assignmentPaul Durrant
The assignment to 'p' is unnecessary as the code will either goto 'invalid' or p will get overwritten. Spotted by Coverity: CID 1398638 Reported-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Paul Durrant <paul.durrant@citrix.com> Acked-by: Anthony PERARD <anthony.perard@citrix.com> Message-Id: <20190215162533.19475-3-paul.durrant@citrix.com> Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
2019-02-04xen-block: handle resize callbackPaul Durrant
Some frontend drivers will handle dynamic resizing of PV disks, so set up the BlockDevOps resize_cb() method during xen_block_realize() to allow this to be done. 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>
2019-01-21hw/block/xen: use proper format string for printing sectorsAlex Bennée
The %lu format string is different depending on the host architecture which causes builds like the debian-armhf-cross build to fail. Use the correct PRi64 format string. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Paul Durrant <paul.durrant@citrix.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> Message-id: 20190116121350.23863-1-alex.bennee@linaro.org Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2019-01-14xen: automatically create XenBlockDevice-sPaul Durrant
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>
2019-01-14xen: add implementations of xen-block connect and disconnect functions...Paul Durrant
...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>
2019-01-14xen: add xenstore watcher infrastructurePaul Durrant
A Xen PV frontend communicates its state to the PV backend by writing to the 'state' key in the frontend area in xenstore. It is therefore necessary for a XenDevice implementation to be notified whenever the value of this key changes. This patch adds code to do this as follows: - an 'fd handler' is registered on the libxenstore handle which will be triggered whenever a 'watch' event occurs - primitives are added to xen-bus-helper to add or remove watch events - a list of Notifier objects is added to XenBus to provide a mechanism to call the appropriate 'watch handler' when its associated event occurs The xen-block implementation is extended with a 'frontend_changed' method, which calls as-yet stub 'connect' and 'disconnect' functions when the relevant frontend state transitions occur. A subsequent patch will supply a full implementation for these functions. 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>
2019-01-14xen: create xenstore areas for XenDevice-sPaul Durrant
This patch adds a new source module, xen-bus-helper.c, which builds on basic libxenstore primitives to provide functions to create (setting permissions appropriately) and destroy xenstore areas, and functions to 'printf' and 'scanf' nodes therein. The main xen-bus code then uses these primitives [1] to initialize and destroy the frontend and backend areas for a XenDevice during realize and unrealize respectively. The 'xen-block' implementation is extended with a 'get_name' method that returns the VBD number. This number is required to 'name' the xenstore areas. NOTE: An exit handler is also added to make sure the xenstore areas are cleaned up if QEMU terminates without devices being unrealized. [1] The 'scanf' functions are actually not yet needed, but they will be needed by code delivered in subsequent patches. 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>
2019-01-14xen: introduce 'xen-block', 'xen-disk' and 'xen-cdrom'Paul Durrant
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>