interface/io/blkif.h

69  *      granted to the frontend.
154  *      by the frontend driver mapped, so the same set of grants should be
160  *      persistently if the frontend supports it. If a backend driver chooses
161  *      to use the persistent protocol when the frontend doesn't support it,
163  *      (due to the fact that the frontend won't be reusing the same grants),
166  *      notifying the frontend depending on memory constraints (this might
173  *      backend driver paired with a LIFO queue in the frontend will
202  *      to offer (or not to offer) discard to the frontend. If the property
244  *            set to 512, unless the frontend advertizes a non-zero value
262  *                            Frontend XenBus Nodes
284  *      For a frontend providing a multi-page ring, a "number of ring pages"
302  *      The size of the frontend allocated request ring buffer in units
312  *      The size of the frontend allocated request ring buffer in units of
322  *      A value of "1" indicates that the frontend will reuse the same grants
324  *      access (even when it should be read-only). If the frontend hits the
329  *      the previous protocol, a frontend driver can choose to work in
332  *      It is recommended that the frontend driver stores the persistently
342  *      A value of "1" indicates that the frontend will correctly supply and
346  *      that the frontend requires that the logical block size is 512 as it
347  *      is hardcoded (which is the case in some frontend implementations).
353  *      A value of "0" indicates that the frontend should not trust the
366  *      frontend's domain.  (e.g. "The first ATA disk", "The third SCSI
388  *     Providing just one of the two may be considered an error by the frontend.
404  * (8) The frontend driver has to allow the backend driver to map all grants
408  *     grants that can be persistently mapped in the frontend driver, but
428  * to avoid distinguishing between a frontend that doesn't understand the
435  * For example, a frontend with two queues must write the following set of
448  * For example, a frontend requests two queues/rings and the size of each ring
498  *                                       o Query frontend transport parameters.
518  *       o A frontend may transition to XenbusStateInitialised without
521  *         transport parameters published by the frontend must contain
525  *         XenbusStateInitWait, without waiting for the frontend to first
589  * present, the frontend might use blkif_request_indirect structs in order to
592  * frontend can issue requests with any number of indirect segments as long as
594  * in blkif_request_indirect should be filled by the frontend with the
625  * of the "feature-large-sector-size" frontend xenbus node above for