linux/include/linux/visorbus.h
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   1// SPDX-License-Identifier: GPL-2.0+
   2/*
   3 * Copyright (C) 2010 - 2013 UNISYS CORPORATION
   4 * All rights reserved.
   5 */
   6
   7/*
   8 *  This header file is to be included by other kernel mode components that
   9 *  implement a particular kind of visor_device.  Each of these other kernel
  10 *  mode components is called a visor device driver.  Refer to visortemplate
  11 *  for a minimal sample visor device driver.
  12 *
  13 *  There should be nothing in this file that is private to the visorbus
  14 *  bus implementation itself.
  15 */
  16
  17#ifndef __VISORBUS_H__
  18#define __VISORBUS_H__
  19
  20#include <linux/device.h>
  21
  22#define VISOR_CHANNEL_SIGNATURE ('L' << 24 | 'N' << 16 | 'C' << 8 | 'E')
  23
  24/*
  25 * enum channel_serverstate
  26 * @CHANNELSRV_UNINITIALIZED: Channel is in an undefined state.
  27 * @CHANNELSRV_READY:         Channel has been initialized by server.
  28 */
  29enum channel_serverstate {
  30        CHANNELSRV_UNINITIALIZED = 0,
  31        CHANNELSRV_READY = 1
  32};
  33
  34/*
  35 * enum channel_clientstate
  36 * @CHANNELCLI_DETACHED:
  37 * @CHANNELCLI_DISABLED:  Client can see channel but is NOT allowed to use it
  38 *                        unless given TBD* explicit request
  39 *                        (should actually be < DETACHED).
  40 * @CHANNELCLI_ATTACHING: Legacy EFI client request for EFI server to attach.
  41 * @CHANNELCLI_ATTACHED:  Idle, but client may want to use channel any time.
  42 * @CHANNELCLI_BUSY:      Client either wants to use or is using channel.
  43 * @CHANNELCLI_OWNED:     "No worries" state - client can access channel
  44 *                        anytime.
  45 */
  46enum channel_clientstate {
  47        CHANNELCLI_DETACHED = 0,
  48        CHANNELCLI_DISABLED = 1,
  49        CHANNELCLI_ATTACHING = 2,
  50        CHANNELCLI_ATTACHED = 3,
  51        CHANNELCLI_BUSY = 4,
  52        CHANNELCLI_OWNED = 5
  53};
  54
  55/*
  56 * Values for VISOR_CHANNEL_PROTOCOL.Features: This define exists so that
  57 * a guest can look at the FeatureFlags in the io channel, and configure the
  58 * driver to use interrupts or not based on this setting. All feature bits for
  59 * all channels should be defined here. The io channel feature bits are defined
  60 * below.
  61 */
  62#define VISOR_DRIVER_ENABLES_INTS (0x1ULL << 1)
  63#define VISOR_CHANNEL_IS_POLLING (0x1ULL << 3)
  64#define VISOR_IOVM_OK_DRIVER_DISABLING_INTS (0x1ULL << 4)
  65#define VISOR_DRIVER_DISABLES_INTS (0x1ULL << 5)
  66#define VISOR_DRIVER_ENHANCED_RCVBUF_CHECKING (0x1ULL << 6)
  67
  68/*
  69 * struct channel_header - Common Channel Header
  70 * @signature:         Signature.
  71 * @legacy_state:      DEPRECATED - being replaced by.
  72 * @header_size:       sizeof(struct channel_header).
  73 * @size:              Total size of this channel in bytes.
  74 * @features:          Flags to modify behavior.
  75 * @chtype:            Channel type: data, bus, control, etc..
  76 * @partition_handle:  ID of guest partition.
  77 * @handle:            Device number of this channel in client.
  78 * @ch_space_offset:   Offset in bytes to channel specific area.
  79 * @version_id:        Struct channel_header Version ID.
  80 * @partition_index:   Index of guest partition.
  81 * @zone_uuid:         Guid of Channel's zone.
  82 * @cli_str_offset:    Offset from channel header to null-terminated
  83 *                     ClientString (0 if ClientString not present).
  84 * @cli_state_boot:    CHANNEL_CLIENTSTATE of pre-boot EFI client of this
  85 *                     channel.
  86 * @cmd_state_cli:     CHANNEL_COMMANDSTATE (overloaded in Windows drivers, see
  87 *                     ServerStateUp, ServerStateDown, etc).
  88 * @cli_state_os:      CHANNEL_CLIENTSTATE of Guest OS client of this channel.
  89 * @ch_characteristic: CHANNEL_CHARACTERISTIC_<xxx>.
  90 * @cmd_state_srv:     CHANNEL_COMMANDSTATE (overloaded in Windows drivers, see
  91 *                     ServerStateUp, ServerStateDown, etc).
  92 * @srv_state:         CHANNEL_SERVERSTATE.
  93 * @cli_error_boot:    Bits to indicate err states for boot clients, so err
  94 *                     messages can be throttled.
  95 * @cli_error_os:      Bits to indicate err states for OS clients, so err
  96 *                     messages can be throttled.
  97 * @filler:            Pad out to 128 byte cacheline.
  98 * @recover_channel:   Please add all new single-byte values below here.
  99 */
 100struct channel_header {
 101        u64 signature;
 102        u32 legacy_state;
 103        /* SrvState, CliStateBoot, and CliStateOS below */
 104        u32 header_size;
 105        u64 size;
 106        u64 features;
 107        guid_t chtype;
 108        u64 partition_handle;
 109        u64 handle;
 110        u64 ch_space_offset;
 111        u32 version_id;
 112        u32 partition_index;
 113        guid_t zone_guid;
 114        u32 cli_str_offset;
 115        u32 cli_state_boot;
 116        u32 cmd_state_cli;
 117        u32 cli_state_os;
 118        u32 ch_characteristic;
 119        u32 cmd_state_srv;
 120        u32 srv_state;
 121        u8 cli_error_boot;
 122        u8 cli_error_os;
 123        u8 filler[1];
 124        u8 recover_channel;
 125} __packed;
 126
 127#define VISOR_CHANNEL_ENABLE_INTS (0x1ULL << 0)
 128
 129/*
 130 * struct signal_queue_header - Subheader for the Signal Type variation of the
 131 *                              Common Channel.
 132 * @version:          SIGNAL_QUEUE_HEADER Version ID.
 133 * @chtype:           Queue type: storage, network.
 134 * @size:             Total size of this queue in bytes.
 135 * @sig_base_offset:  Offset to signal queue area.
 136 * @features:         Flags to modify behavior.
 137 * @num_sent:         Total # of signals placed in this queue.
 138 * @num_overflows:    Total # of inserts failed due to full queue.
 139 * @signal_size:      Total size of a signal for this queue.
 140 * @max_slots:        Max # of slots in queue, 1 slot is always empty.
 141 * @max_signals:      Max # of signals in queue (MaxSignalSlots-1).
 142 * @head:             Queue head signal #.
 143 * @num_received:     Total # of signals removed from this queue.
 144 * @tail:             Queue tail signal.
 145 * @reserved1:        Reserved field.
 146 * @reserved2:        Reserved field.
 147 * @client_queue:
 148 * @num_irq_received: Total # of Interrupts received. This is incremented by the
 149 *                    ISR in the guest windows driver.
 150 * @num_empty:        Number of times that visor_signal_remove is called and
 151 *                    returned Empty Status.
 152 * @errorflags:       Error bits set during SignalReinit to denote trouble with
 153 *                    client's fields.
 154 * @filler:           Pad out to 64 byte cacheline.
 155 */
 156struct signal_queue_header {
 157        /* 1st cache line */
 158        u32 version;
 159        u32 chtype;
 160        u64 size;
 161        u64 sig_base_offset;
 162        u64 features;
 163        u64 num_sent;
 164        u64 num_overflows;
 165        u32 signal_size;
 166        u32 max_slots;
 167        u32 max_signals;
 168        u32 head;
 169        /* 2nd cache line */
 170        u64 num_received;
 171        u32 tail;
 172        u32 reserved1;
 173        u64 reserved2;
 174        u64 client_queue;
 175        u64 num_irq_received;
 176        u64 num_empty;
 177        u32 errorflags;
 178        u8 filler[12];
 179} __packed;
 180
 181/* VISORCHANNEL Guids */
 182/* {414815ed-c58c-11da-95a9-00e08161165f} */
 183#define VISOR_VHBA_CHANNEL_GUID \
 184        GUID_INIT(0x414815ed, 0xc58c, 0x11da, \
 185                  0x95, 0xa9, 0x0, 0xe0, 0x81, 0x61, 0x16, 0x5f)
 186#define VISOR_VHBA_CHANNEL_GUID_STR \
 187        "414815ed-c58c-11da-95a9-00e08161165f"
 188struct visorchipset_state {
 189        u32 created:1;
 190        u32 attached:1;
 191        u32 configured:1;
 192        u32 running:1;
 193        /* Remaining bits in this 32-bit word are reserved. */
 194};
 195
 196/**
 197 * struct visor_device - A device type for things "plugged" into the visorbus
 198 *                       bus
 199 * @visorchannel:               Points to the channel that the device is
 200 *                              associated with.
 201 * @channel_type_guid:          Identifies the channel type to the bus driver.
 202 * @device:                     Device struct meant for use by the bus driver
 203 *                              only.
 204 * @list_all:                   Used by the bus driver to enumerate devices.
 205 * @timer:                      Timer fired periodically to do interrupt-type
 206 *                              activity.
 207 * @being_removed:              Indicates that the device is being removed from
 208 *                              the bus. Private bus driver use only.
 209 * @visordriver_callback_lock:  Used by the bus driver to lock when adding and
 210 *                              removing devices.
 211 * @pausing:                    Indicates that a change towards a paused state.
 212 *                              is in progress. Only modified by the bus driver.
 213 * @resuming:                   Indicates that a change towards a running state
 214 *                              is in progress. Only modified by the bus driver.
 215 * @chipset_bus_no:             Private field used by the bus driver.
 216 * @chipset_dev_no:             Private field used the bus driver.
 217 * @state:                      Used to indicate the current state of the
 218 *                              device.
 219 * @inst:                       Unique GUID for this instance of the device.
 220 * @name:                       Name of the device.
 221 * @pending_msg_hdr:            For private use by bus driver to respond to
 222 *                              hypervisor requests.
 223 * @vbus_hdr_info:              A pointer to header info. Private use by bus
 224 *                              driver.
 225 * @partition_guid:             Indicates client partion id. This should be the
 226 *                              same across all visor_devices in the current
 227 *                              guest. Private use by bus driver only.
 228 */
 229struct visor_device {
 230        struct visorchannel *visorchannel;
 231        guid_t channel_type_guid;
 232        /* These fields are for private use by the bus driver only. */
 233        struct device device;
 234        struct list_head list_all;
 235        struct timer_list timer;
 236        bool timer_active;
 237        bool being_removed;
 238        struct mutex visordriver_callback_lock; /* synchronize probe/remove */
 239        bool pausing;
 240        bool resuming;
 241        u32 chipset_bus_no;
 242        u32 chipset_dev_no;
 243        struct visorchipset_state state;
 244        guid_t inst;
 245        u8 *name;
 246        struct controlvm_message_header *pending_msg_hdr;
 247        void *vbus_hdr_info;
 248        guid_t partition_guid;
 249        struct dentry *debugfs_dir;
 250        struct dentry *debugfs_bus_info;
 251};
 252
 253#define to_visor_device(x) container_of(x, struct visor_device, device)
 254
 255typedef void (*visorbus_state_complete_func) (struct visor_device *dev,
 256                                              int status);
 257
 258/*
 259 * This struct describes a specific visor channel, by providing its GUID, name,
 260 * and sizes.
 261 */
 262struct visor_channeltype_descriptor {
 263        const guid_t guid;
 264        const char *name;
 265        u64 min_bytes;
 266        u32 version;
 267};
 268
 269/**
 270 * struct visor_driver - Information provided by each visor driver when it
 271 *                       registers with the visorbus driver
 272 * @name:               Name of the visor driver.
 273 * @owner:              The module owner.
 274 * @channel_types:      Types of channels handled by this driver, ending with
 275 *                      a zero GUID. Our specialized BUS.match() method knows
 276 *                      about this list, and uses it to determine whether this
 277 *                      driver will in fact handle a new device that it has
 278 *                      detected.
 279 * @probe:              Called when a new device comes online, by our probe()
 280 *                      function specified by driver.probe() (triggered
 281 *                      ultimately by some call to driver_register(),
 282 *                      bus_add_driver(), or driver_attach()).
 283 * @remove:             Called when a new device is removed, by our remove()
 284 *                      function specified by driver.remove() (triggered
 285 *                      ultimately by some call to device_release_driver()).
 286 * @channel_interrupt:  Called periodically, whenever there is a possiblity
 287 *                      that "something interesting" may have happened to the
 288 *                      channel.
 289 * @pause:              Called to initiate a change of the device's state.  If
 290 *                      the return valu`e is < 0, there was an error and the
 291 *                      state transition will NOT occur.  If the return value
 292 *                      is >= 0, then the state transition was INITIATED
 293 *                      successfully, and complete_func() will be called (or
 294 *                      was just called) with the final status when either the
 295 *                      state transition fails or completes successfully.
 296 * @resume:             Behaves similar to pause.
 297 * @driver:             Private reference to the device driver. For use by bus
 298 *                      driver only.
 299 */
 300struct visor_driver {
 301        const char *name;
 302        struct module *owner;
 303        struct visor_channeltype_descriptor *channel_types;
 304        int (*probe)(struct visor_device *dev);
 305        void (*remove)(struct visor_device *dev);
 306        void (*channel_interrupt)(struct visor_device *dev);
 307        int (*pause)(struct visor_device *dev,
 308                     visorbus_state_complete_func complete_func);
 309        int (*resume)(struct visor_device *dev,
 310                      visorbus_state_complete_func complete_func);
 311
 312        /* These fields are for private use by the bus driver only. */
 313        struct device_driver driver;
 314};
 315
 316#define to_visor_driver(x) (container_of(x, struct visor_driver, driver))
 317
 318int visor_check_channel(struct channel_header *ch, struct device *dev,
 319                        const guid_t *expected_uuid, char *chname,
 320                        u64 expected_min_bytes, u32 expected_version,
 321                        u64 expected_signature);
 322
 323int visorbus_register_visor_driver(struct visor_driver *drv);
 324void visorbus_unregister_visor_driver(struct visor_driver *drv);
 325int visorbus_read_channel(struct visor_device *dev,
 326                          unsigned long offset, void *dest,
 327                          unsigned long nbytes);
 328int visorbus_write_channel(struct visor_device *dev,
 329                           unsigned long offset, void *src,
 330                           unsigned long nbytes);
 331int visorbus_enable_channel_interrupts(struct visor_device *dev);
 332void visorbus_disable_channel_interrupts(struct visor_device *dev);
 333
 334int visorchannel_signalremove(struct visorchannel *channel, u32 queue,
 335                              void *msg);
 336int visorchannel_signalinsert(struct visorchannel *channel, u32 queue,
 337                              void *msg);
 338bool visorchannel_signalempty(struct visorchannel *channel, u32 queue);
 339const guid_t *visorchannel_get_guid(struct visorchannel *channel);
 340
 341#define BUS_ROOT_DEVICE UINT_MAX
 342struct visor_device *visorbus_get_device_by_id(u32 bus_no, u32 dev_no,
 343                                               struct visor_device *from);
 344#endif
 345