/* SPDX-License-Identifier: MIT */ /****************************************************************************** * displif.h * * Unified display device I/O interface for Xen guest OSes. * * Copyright (C) 2016-2017 EPAM Systems Inc. * * Authors: Oleksandr Andrushchenko <[email protected]> * Oleksandr Grytsov <[email protected]> */ #ifndef __XEN_PUBLIC_IO_DISPLIF_H__ #define __XEN_PUBLIC_IO_DISPLIF_H__ #include "ring.h" #include "../grant_table.h" /* ****************************************************************************** * Protocol version ****************************************************************************** */ #define XENDISPL_PROTOCOL_VERSION … #define XENDISPL_PROTOCOL_VERSION_INT … /* ****************************************************************************** * Main features provided by the protocol ****************************************************************************** * This protocol aims to provide a unified protocol which fits more * sophisticated use-cases than a framebuffer device can handle. At the * moment basic functionality is supported with the intention to be extended: * o multiple dynamically allocated/destroyed framebuffers * o buffers of arbitrary sizes * o buffer allocation at either back or front end * o better configuration options including multiple display support * * Note: existing fbif can be used together with displif running at the * same time, e.g. on Linux one provides framebuffer and another DRM/KMS * * Note: display resolution (XenStore's "resolution" property) defines * visible area of the virtual display. At the same time resolution of * the display and frame buffers may differ: buffers can be smaller, equal * or bigger than the visible area. This is to enable use-cases, where backend * may do some post-processing of the display and frame buffers supplied, * e.g. those buffers can be just a part of the final composition. * ****************************************************************************** * Direction of improvements ****************************************************************************** * Future extensions to the existing protocol may include: * o display/connector cloning * o allocation of objects other than display buffers * o plane/overlay support * o scaling support * o rotation support * ****************************************************************************** * Feature and Parameter Negotiation ****************************************************************************** * * Front->back notifications: when enqueuing a new request, sending a * notification can be made conditional on xendispl_req (i.e., the generic * hold-off mechanism provided by the ring macros). Backends must set * xendispl_req appropriately (e.g., using RING_FINAL_CHECK_FOR_REQUESTS()). * * Back->front notifications: when enqueuing a new response, sending a * notification can be made conditional on xendispl_resp (i.e., the generic * hold-off mechanism provided by the ring macros). Frontends must set * xendispl_resp appropriately (e.g., using RING_FINAL_CHECK_FOR_RESPONSES()). * * The two halves of a para-virtual display driver utilize nodes within * XenStore to communicate capabilities and to negotiate operating parameters. * This section enumerates these nodes which reside in the respective front and * backend portions of XenStore, following the XenBus convention. * * All data in XenStore is stored as strings. Nodes specifying numeric * values are encoded in decimal. Integer value ranges listed below are * expressed as fixed sized integer types capable of storing the conversion * of a properly formated node string, without loss of information. * ****************************************************************************** * Example configuration ****************************************************************************** * * Note: depending on the use-case backend can expose more display connectors * than the underlying HW physically has by employing SW graphics compositors * * This is an example of backend and frontend configuration: * *--------------------------------- Backend ----------------------------------- * * /local/domain/0/backend/vdispl/1/0/frontend-id = "1" * /local/domain/0/backend/vdispl/1/0/frontend = "/local/domain/1/device/vdispl/0" * /local/domain/0/backend/vdispl/1/0/state = "4" * /local/domain/0/backend/vdispl/1/0/versions = "1,2" * *--------------------------------- Frontend ---------------------------------- * * /local/domain/1/device/vdispl/0/backend-id = "0" * /local/domain/1/device/vdispl/0/backend = "/local/domain/0/backend/vdispl/1/0" * /local/domain/1/device/vdispl/0/state = "4" * /local/domain/1/device/vdispl/0/version = "1" * /local/domain/1/device/vdispl/0/be-alloc = "1" * *-------------------------- Connector 0 configuration ------------------------ * * /local/domain/1/device/vdispl/0/0/resolution = "1920x1080" * /local/domain/1/device/vdispl/0/0/req-ring-ref = "2832" * /local/domain/1/device/vdispl/0/0/req-event-channel = "15" * /local/domain/1/device/vdispl/0/0/evt-ring-ref = "387" * /local/domain/1/device/vdispl/0/0/evt-event-channel = "16" * *-------------------------- Connector 1 configuration ------------------------ * * /local/domain/1/device/vdispl/0/1/resolution = "800x600" * /local/domain/1/device/vdispl/0/1/req-ring-ref = "2833" * /local/domain/1/device/vdispl/0/1/req-event-channel = "17" * /local/domain/1/device/vdispl/0/1/evt-ring-ref = "388" * /local/domain/1/device/vdispl/0/1/evt-event-channel = "18" * ****************************************************************************** * Backend XenBus Nodes ****************************************************************************** * *----------------------------- Protocol version ------------------------------ * * versions * Values: <string> * * List of XENDISPL_LIST_SEPARATOR separated protocol versions supported * by the backend. For example "1,2,3". * ****************************************************************************** * Frontend XenBus Nodes ****************************************************************************** * *-------------------------------- Addressing --------------------------------- * * dom-id * Values: <uint16_t> * * Domain identifier. * * dev-id * Values: <uint16_t> * * Device identifier. * * conn-idx * Values: <uint8_t> * * Zero based contigous index of the connector. * /local/domain/<dom-id>/device/vdispl/<dev-id>/<conn-idx>/... * *----------------------------- Protocol version ------------------------------ * * version * Values: <string> * * Protocol version, chosen among the ones supported by the backend. * *------------------------- Backend buffer allocation ------------------------- * * be-alloc * Values: "0", "1" * * If value is set to "1", then backend can be a buffer provider/allocator * for this domain during XENDISPL_OP_DBUF_CREATE operation (see below * for negotiation). * If value is not "1" or omitted frontend must allocate buffers itself. * *----------------------------- Connector settings ---------------------------- * * unique-id * Values: <string> * * After device instance initialization each connector is assigned a * unique ID, so it can be identified by the backend by this ID. * This can be UUID or such. * * resolution * Values: <width, uint32_t>x<height, uint32_t> * * Width and height of the connector in pixels separated by * XENDISPL_RESOLUTION_SEPARATOR. This defines visible area of the * display. * If backend provides extended display identification data (EDID) with * XENDISPL_OP_GET_EDID request then EDID values must take precedence * over the resolutions defined here. * *------------------ Connector Request Transport Parameters ------------------- * * This communication path is used to deliver requests from frontend to backend * and get the corresponding responses from backend to frontend, * set up per connector. * * req-event-channel * Values: <uint32_t> * * The identifier of the Xen connector's control event channel * used to signal activity in the ring buffer. * * req-ring-ref * Values: <uint32_t> * * The Xen grant reference granting permission for the backend to map * a sole page of connector's control ring buffer. * *------------------- Connector Event Transport Parameters -------------------- * * This communication path is used to deliver asynchronous events from backend * to frontend, set up per connector. * * evt-event-channel * Values: <uint32_t> * * The identifier of the Xen connector's event channel * used to signal activity in the ring buffer. * * evt-ring-ref * Values: <uint32_t> * * The Xen grant reference granting permission for the backend to map * a sole page of connector's event ring buffer. */ /* ****************************************************************************** * STATE DIAGRAMS ****************************************************************************** * * Tool stack creates front and back state nodes with initial state * XenbusStateInitialising. * Tool stack creates and sets up frontend display configuration * nodes per domain. * *-------------------------------- Normal flow -------------------------------- * * Front Back * ================================= ===================================== * XenbusStateInitialising XenbusStateInitialising * o Query backend device identification * data. * o Open and validate backend device. * | * | * V * XenbusStateInitWait * * o Query frontend configuration * o Allocate and initialize * event channels per configured * connector. * o Publish transport parameters * that will be in effect during * this connection. * | * | * V * XenbusStateInitialised * * o Query frontend transport parameters. * o Connect to the event channels. * | * | * V * XenbusStateConnected * * o Create and initialize OS * virtual display connectors * as per configuration. * | * | * V * XenbusStateConnected * * XenbusStateUnknown * XenbusStateClosed * XenbusStateClosing * o Remove virtual display device * o Remove event channels * | * | * V * XenbusStateClosed * *------------------------------- Recovery flow ------------------------------- * * In case of frontend unrecoverable errors backend handles that as * if frontend goes into the XenbusStateClosed state. * * In case of backend unrecoverable errors frontend tries removing * the virtualized device. If this is possible at the moment of error, * then frontend goes into the XenbusStateInitialising state and is ready for * new connection with backend. If the virtualized device is still in use and * cannot be removed, then frontend goes into the XenbusStateReconfiguring state * until either the virtualized device is removed or backend initiates a new * connection. On the virtualized device removal frontend goes into the * XenbusStateInitialising state. * * Note on XenbusStateReconfiguring state of the frontend: if backend has * unrecoverable errors then frontend cannot send requests to the backend * and thus cannot provide functionality of the virtualized device anymore. * After backend is back to normal the virtualized device may still hold some * state: configuration in use, allocated buffers, client application state etc. * In most cases, this will require frontend to implement complex recovery * reconnect logic. Instead, by going into XenbusStateReconfiguring state, * frontend will make sure no new clients of the virtualized device are * accepted, allow existing client(s) to exit gracefully by signaling error * state etc. * Once all the clients are gone frontend can reinitialize the virtualized * device and get into XenbusStateInitialising state again signaling the * backend that a new connection can be made. * * There are multiple conditions possible under which frontend will go from * XenbusStateReconfiguring into XenbusStateInitialising, some of them are OS * specific. For example: * 1. The underlying OS framework may provide callbacks to signal that the last * client of the virtualized device has gone and the device can be removed * 2. Frontend can schedule a deferred work (timer/tasklet/workqueue) * to periodically check if this is the right time to re-try removal of * the virtualized device. * 3. By any other means. * ****************************************************************************** * REQUEST CODES ****************************************************************************** * Request codes [0; 15] are reserved and must not be used */ #define XENDISPL_OP_DBUF_CREATE … #define XENDISPL_OP_DBUF_DESTROY … #define XENDISPL_OP_FB_ATTACH … #define XENDISPL_OP_FB_DETACH … #define XENDISPL_OP_SET_CONFIG … #define XENDISPL_OP_PG_FLIP … /* The below command is available in protocol version 2 and above. */ #define XENDISPL_OP_GET_EDID … /* ****************************************************************************** * EVENT CODES ****************************************************************************** */ #define XENDISPL_EVT_PG_FLIP … /* ****************************************************************************** * XENSTORE FIELD AND PATH NAME STRINGS, HELPERS ****************************************************************************** */ #define XENDISPL_DRIVER_NAME … #define XENDISPL_LIST_SEPARATOR … #define XENDISPL_RESOLUTION_SEPARATOR … #define XENDISPL_FIELD_BE_VERSIONS … #define XENDISPL_FIELD_FE_VERSION … #define XENDISPL_FIELD_REQ_RING_REF … #define XENDISPL_FIELD_REQ_CHANNEL … #define XENDISPL_FIELD_EVT_RING_REF … #define XENDISPL_FIELD_EVT_CHANNEL … #define XENDISPL_FIELD_RESOLUTION … #define XENDISPL_FIELD_BE_ALLOC … #define XENDISPL_FIELD_UNIQUE_ID … #define XENDISPL_EDID_BLOCK_SIZE … #define XENDISPL_EDID_BLOCK_COUNT … #define XENDISPL_EDID_MAX_SIZE … /* ****************************************************************************** * STATUS RETURN CODES ****************************************************************************** * * Status return code is zero on success and -XEN_EXX on failure. * ****************************************************************************** * Assumptions ****************************************************************************** * o usage of grant reference 0 as invalid grant reference: * grant reference 0 is valid, but never exposed to a PV driver, * because of the fact it is already in use/reserved by the PV console. * o all references in this document to page sizes must be treated * as pages of size XEN_PAGE_SIZE unless otherwise noted. * ****************************************************************************** * Description of the protocol between frontend and backend driver ****************************************************************************** * * The two halves of a Para-virtual display driver communicate with * each other using shared pages and event channels. * Shared page contains a ring with request/response packets. * * All reserved fields in the structures below must be 0. * Display buffers's cookie of value 0 is treated as invalid. * Framebuffer's cookie of value 0 is treated as invalid. * * For all request/response/event packets that use cookies: * dbuf_cookie - uint64_t, unique to guest domain value used by the backend * to map remote display buffer to its local one * fb_cookie - uint64_t, unique to guest domain value used by the backend * to map remote framebuffer to its local one * *---------------------------------- Requests --------------------------------- * * All requests/responses, which are not connector specific, must be sent over * control ring of the connector which has the index value of 0: * /local/domain/<dom-id>/device/vdispl/<dev-id>/0/req-ring-ref * * All request packets have the same length (64 octets) * All request packets have common header: * 0 1 2 3 octet * +----------------+----------------+----------------+----------------+ * | id | operation | reserved | 4 * +----------------+----------------+----------------+----------------+ * | reserved | 8 * +----------------+----------------+----------------+----------------+ * id - uint16_t, private guest value, echoed in response * operation - uint8_t, operation code, XENDISPL_OP_??? * * Request dbuf creation - request creation of a display buffer. * 0 1 2 3 octet * +----------------+----------------+----------------+----------------+ * | id |_OP_DBUF_CREATE | reserved | 4 * +----------------+----------------+----------------+----------------+ * | reserved | 8 * +----------------+----------------+----------------+----------------+ * | dbuf_cookie low 32-bit | 12 * +----------------+----------------+----------------+----------------+ * | dbuf_cookie high 32-bit | 16 * +----------------+----------------+----------------+----------------+ * | width | 20 * +----------------+----------------+----------------+----------------+ * | height | 24 * +----------------+----------------+----------------+----------------+ * | bpp | 28 * +----------------+----------------+----------------+----------------+ * | buffer_sz | 32 * +----------------+----------------+----------------+----------------+ * | flags | 36 * +----------------+----------------+----------------+----------------+ * | gref_directory | 40 * +----------------+----------------+----------------+----------------+ * | data_ofs | 44 * +----------------+----------------+----------------+----------------+ * | reserved | 48 * +----------------+----------------+----------------+----------------+ * |/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/| * +----------------+----------------+----------------+----------------+ * | reserved | 64 * +----------------+----------------+----------------+----------------+ * * Must be sent over control ring of the connector which has the index * value of 0: * /local/domain/<dom-id>/device/vdispl/<dev-id>/0/req-ring-ref * All unused bits in flags field must be set to 0. * * An attempt to create multiple display buffers with the same dbuf_cookie is * an error. dbuf_cookie can be re-used after destroying the corresponding * display buffer. * * Width and height of the display buffers can be smaller, equal or bigger * than the connector's resolution. Depth/pixel format of the individual * buffers can differ as well. * * width - uint32_t, width in pixels * height - uint32_t, height in pixels * bpp - uint32_t, bits per pixel * buffer_sz - uint32_t, buffer size to be allocated, octets * flags - uint32_t, flags of the operation * o XENDISPL_DBUF_FLG_REQ_ALLOC - if set, then backend is requested * to allocate the buffer with the parameters provided in this request. * Page directory is handled as follows: * Frontend on request: * o allocates pages for the directory (gref_directory, * gref_dir_next_page(s) * o grants permissions for the pages of the directory to the backend * o sets gref_dir_next_page fields * Backend on response: * o grants permissions for the pages of the buffer allocated to * the frontend * o fills in page directory with grant references * (gref[] in struct xendispl_page_directory) * gref_directory - grant_ref_t, a reference to the first shared page * describing shared buffer references. At least one page exists. If shared * buffer size (buffer_sz) exceeds what can be addressed by this single page, * then reference to the next page must be supplied (see gref_dir_next_page * below) * data_ofs - uint32_t, offset of the data in the buffer, octets */ #define XENDISPL_DBUF_FLG_REQ_ALLOC … struct xendispl_dbuf_create_req { … }; /* * Shared page for XENDISPL_OP_DBUF_CREATE buffer descriptor (gref_directory in * the request) employs a list of pages, describing all pages of the shared * data buffer: * 0 1 2 3 octet * +----------------+----------------+----------------+----------------+ * | gref_dir_next_page | 4 * +----------------+----------------+----------------+----------------+ * | gref[0] | 8 * +----------------+----------------+----------------+----------------+ * |/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/| * +----------------+----------------+----------------+----------------+ * | gref[i] | i*4+8 * +----------------+----------------+----------------+----------------+ * |/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/| * +----------------+----------------+----------------+----------------+ * | gref[N - 1] | N*4+8 * +----------------+----------------+----------------+----------------+ * * gref_dir_next_page - grant_ref_t, reference to the next page describing * page directory. Must be 0 if there are no more pages in the list. * gref[i] - grant_ref_t, reference to a shared page of the buffer * allocated at XENDISPL_OP_DBUF_CREATE * * Number of grant_ref_t entries in the whole page directory is not * passed, but instead can be calculated as: * num_grefs_total = (XENDISPL_OP_DBUF_CREATE.buffer_sz + XEN_PAGE_SIZE - 1) / * XEN_PAGE_SIZE */ struct xendispl_page_directory { … }; /* * Request dbuf destruction - destroy a previously allocated display buffer: * 0 1 2 3 octet * +----------------+----------------+----------------+----------------+ * | id |_OP_DBUF_DESTROY| reserved | 4 * +----------------+----------------+----------------+----------------+ * | reserved | 8 * +----------------+----------------+----------------+----------------+ * | dbuf_cookie low 32-bit | 12 * +----------------+----------------+----------------+----------------+ * | dbuf_cookie high 32-bit | 16 * +----------------+----------------+----------------+----------------+ * | reserved | 20 * +----------------+----------------+----------------+----------------+ * |/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/| * +----------------+----------------+----------------+----------------+ * | reserved | 64 * +----------------+----------------+----------------+----------------+ * * Must be sent over control ring of the connector which has the index * value of 0: * /local/domain/<dom-id>/device/vdispl/<dev-id>/0/req-ring-ref */ struct xendispl_dbuf_destroy_req { … }; /* * Request framebuffer attachment - request attachment of a framebuffer to * previously created display buffer. * 0 1 2 3 octet * +----------------+----------------+----------------+----------------+ * | id | _OP_FB_ATTACH | reserved | 4 * +----------------+----------------+----------------+----------------+ * | reserved | 8 * +----------------+----------------+----------------+----------------+ * | dbuf_cookie low 32-bit | 12 * +----------------+----------------+----------------+----------------+ * | dbuf_cookie high 32-bit | 16 * +----------------+----------------+----------------+----------------+ * | fb_cookie low 32-bit | 20 * +----------------+----------------+----------------+----------------+ * | fb_cookie high 32-bit | 24 * +----------------+----------------+----------------+----------------+ * | width | 28 * +----------------+----------------+----------------+----------------+ * | height | 32 * +----------------+----------------+----------------+----------------+ * | pixel_format | 36 * +----------------+----------------+----------------+----------------+ * | reserved | 40 * +----------------+----------------+----------------+----------------+ * |/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/| * +----------------+----------------+----------------+----------------+ * | reserved | 64 * +----------------+----------------+----------------+----------------+ * * Must be sent over control ring of the connector which has the index * value of 0: * /local/domain/<dom-id>/device/vdispl/<dev-id>/0/req-ring-ref * Width and height can be smaller, equal or bigger than the connector's * resolution. * * An attempt to create multiple frame buffers with the same fb_cookie is * an error. fb_cookie can be re-used after destroying the corresponding * frame buffer. * * width - uint32_t, width in pixels * height - uint32_t, height in pixels * pixel_format - uint32_t, pixel format of the framebuffer, FOURCC code */ struct xendispl_fb_attach_req { … }; /* * Request framebuffer detach - detach a previously * attached framebuffer from the display buffer in request: * 0 1 2 3 octet * +----------------+----------------+----------------+----------------+ * | id | _OP_FB_DETACH | reserved | 4 * +----------------+----------------+----------------+----------------+ * | reserved | 8 * +----------------+----------------+----------------+----------------+ * | fb_cookie low 32-bit | 12 * +----------------+----------------+----------------+----------------+ * | fb_cookie high 32-bit | 16 * +----------------+----------------+----------------+----------------+ * | reserved | 20 * +----------------+----------------+----------------+----------------+ * |/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/| * +----------------+----------------+----------------+----------------+ * | reserved | 64 * +----------------+----------------+----------------+----------------+ * * Must be sent over control ring of the connector which has the index * value of 0: * /local/domain/<dom-id>/device/vdispl/<dev-id>/0/req-ring-ref */ struct xendispl_fb_detach_req { … }; /* * Request configuration set/reset - request to set or reset * the configuration/mode of the display: * 0 1 2 3 octet * +----------------+----------------+----------------+----------------+ * | id | _OP_SET_CONFIG | reserved | 4 * +----------------+----------------+----------------+----------------+ * | reserved | 8 * +----------------+----------------+----------------+----------------+ * | fb_cookie low 32-bit | 12 * +----------------+----------------+----------------+----------------+ * | fb_cookie high 32-bit | 16 * +----------------+----------------+----------------+----------------+ * | x | 20 * +----------------+----------------+----------------+----------------+ * | y | 24 * +----------------+----------------+----------------+----------------+ * | width | 28 * +----------------+----------------+----------------+----------------+ * | height | 32 * +----------------+----------------+----------------+----------------+ * | bpp | 40 * +----------------+----------------+----------------+----------------+ * | reserved | 44 * +----------------+----------------+----------------+----------------+ * |/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/| * +----------------+----------------+----------------+----------------+ * | reserved | 64 * +----------------+----------------+----------------+----------------+ * * Pass all zeros to reset, otherwise command is treated as * configuration set. * Framebuffer's cookie defines which framebuffer/dbuf must be * displayed while enabling display (applying configuration). * x, y, width and height are bound by the connector's resolution and must not * exceed it. * * x - uint32_t, starting position in pixels by X axis * y - uint32_t, starting position in pixels by Y axis * width - uint32_t, width in pixels * height - uint32_t, height in pixels * bpp - uint32_t, bits per pixel */ struct xendispl_set_config_req { … }; /* * Request page flip - request to flip a page identified by the framebuffer * cookie: * 0 1 2 3 octet * +----------------+----------------+----------------+----------------+ * | id | _OP_PG_FLIP | reserved | 4 * +----------------+----------------+----------------+----------------+ * | reserved | 8 * +----------------+----------------+----------------+----------------+ * | fb_cookie low 32-bit | 12 * +----------------+----------------+----------------+----------------+ * | fb_cookie high 32-bit | 16 * +----------------+----------------+----------------+----------------+ * | reserved | 20 * +----------------+----------------+----------------+----------------+ * |/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/| * +----------------+----------------+----------------+----------------+ * | reserved | 64 * +----------------+----------------+----------------+----------------+ */ struct xendispl_page_flip_req { … }; /* * Request EDID - request EDID describing current connector: * 0 1 2 3 octet * +----------------+----------------+----------------+----------------+ * | id | _OP_GET_EDID | reserved | 4 * +----------------+----------------+----------------+----------------+ * | buffer_sz | 8 * +----------------+----------------+----------------+----------------+ * | gref_directory | 12 * +----------------+----------------+----------------+----------------+ * | reserved | 16 * +----------------+----------------+----------------+----------------+ * |/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/| * +----------------+----------------+----------------+----------------+ * | reserved | 64 * +----------------+----------------+----------------+----------------+ * * Notes: * - This command is not available in protocol version 1 and should be * ignored. * - This request is optional and if not supported then visible area * is defined by the relevant XenStore's "resolution" property. * - Shared buffer, allocated for EDID storage, must not be less then * XENDISPL_EDID_MAX_SIZE octets. * * buffer_sz - uint32_t, buffer size to be allocated, octets * gref_directory - grant_ref_t, a reference to the first shared page * describing EDID buffer references. See XENDISPL_OP_DBUF_CREATE for * grant page directory structure (struct xendispl_page_directory). * * See response format for this request. */ struct xendispl_get_edid_req { … }; /* *---------------------------------- Responses -------------------------------- * * All response packets have the same length (64 octets) * * All response packets have common header: * 0 1 2 3 octet * +----------------+----------------+----------------+----------------+ * | id | reserved | 4 * +----------------+----------------+----------------+----------------+ * | status | 8 * +----------------+----------------+----------------+----------------+ * | reserved | 12 * +----------------+----------------+----------------+----------------+ * |/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/| * +----------------+----------------+----------------+----------------+ * | reserved | 64 * +----------------+----------------+----------------+----------------+ * * id - uint16_t, private guest value, echoed from request * status - int32_t, response status, zero on success and -XEN_EXX on failure * * * Get EDID response - response for XENDISPL_OP_GET_EDID: * 0 1 2 3 octet * +----------------+----------------+----------------+----------------+ * | id | operation | reserved | 4 * +----------------+----------------+----------------+----------------+ * | status | 8 * +----------------+----------------+----------------+----------------+ * | edid_sz | 12 * +----------------+----------------+----------------+----------------+ * | reserved | 16 * +----------------+----------------+----------------+----------------+ * |/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/| * +----------------+----------------+----------------+----------------+ * | reserved | 64 * +----------------+----------------+----------------+----------------+ * * Notes: * - This response is not available in protocol version 1 and should be * ignored. * * edid_sz - uint32_t, size of the EDID, octets */ struct xendispl_get_edid_resp { … }; /* *----------------------------------- Events ---------------------------------- * * Events are sent via a shared page allocated by the front and propagated by * evt-event-channel/evt-ring-ref XenStore entries * All event packets have the same length (64 octets) * All event packets have common header: * 0 1 2 3 octet * +----------------+----------------+----------------+----------------+ * | id | type | reserved | 4 * +----------------+----------------+----------------+----------------+ * | reserved | 8 * +----------------+----------------+----------------+----------------+ * * id - uint16_t, event id, may be used by front * type - uint8_t, type of the event * * * Page flip complete event - event from back to front on page flip completed: * 0 1 2 3 octet * +----------------+----------------+----------------+----------------+ * | id | _EVT_PG_FLIP | reserved | 4 * +----------------+----------------+----------------+----------------+ * | reserved | 8 * +----------------+----------------+----------------+----------------+ * | fb_cookie low 32-bit | 12 * +----------------+----------------+----------------+----------------+ * | fb_cookie high 32-bit | 16 * +----------------+----------------+----------------+----------------+ * | reserved | 20 * +----------------+----------------+----------------+----------------+ * |/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/| * +----------------+----------------+----------------+----------------+ * | reserved | 64 * +----------------+----------------+----------------+----------------+ */ struct xendispl_pg_flip_evt { … }; struct xendispl_req { … }; struct xendispl_resp { … }; struct xendispl_evt { … }; DEFINE_RING_TYPES(xen_displif, struct xendispl_req, struct xendispl_resp); /* ****************************************************************************** * Back to front events delivery ****************************************************************************** * In order to deliver asynchronous events from back to front a shared page is * allocated by front and its granted reference propagated to back via * XenStore entries (evt-ring-ref/evt-event-channel). * This page has a common header used by both front and back to synchronize * access and control event's ring buffer, while back being a producer of the * events and front being a consumer. The rest of the page after the header * is used for event packets. * * Upon reception of an event(s) front may confirm its reception * for either each event, group of events or none. */ struct xendispl_event_page { … }; #define XENDISPL_EVENT_PAGE_SIZE … #define XENDISPL_IN_RING_OFFS … #define XENDISPL_IN_RING_SIZE … #define XENDISPL_IN_RING_LEN … #define XENDISPL_IN_RING(page) … #define XENDISPL_IN_RING_REF(page, idx) … #endif /* __XEN_PUBLIC_IO_DISPLIF_H__ */
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