drivers/hv/hv_fcopy.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * An implementation of file copy service.
   4  *
   5  * Copyright (C) 2014, Microsoft, Inc.
   6  *
   7  * Author : K. Y. Srinivasan <ksrinivasan@novell.com>
   8  */
   9
  10 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  11
  12 #include <linux/nls.h>
  13 #include <linux/workqueue.h>
  14 #include <linux/hyperv.h>
  15 #include <linux/sched.h>
  16 #include <asm/hyperv-tlfs.h>
  17
  18 #include "hyperv_vmbus.h"
  19 #include "hv_utils_transport.h"
  20
  21 #define WIN8_SRV_MAJOR          1
  22 #define WIN8_SRV_MINOR          1
  23 #define WIN8_SRV_VERSION        (WIN8_SRV_MAJOR << 16 | WIN8_SRV_MINOR)
  24
  25 #define FCOPY_VER_COUNT 1
  26 static const int fcopy_versions[] = {
  27         WIN8_SRV_VERSION
  28 };
  29
  30 #define FW_VER_COUNT 1
  31 static const int fw_versions[] = {
  32         UTIL_FW_VERSION
  33 };
  34
  35 /*
  36  * Global state maintained for transaction that is being processed.
  37  * For a class of integration services, including the "file copy service",
  38  * the specified protocol is a "request/response" protocol which means that
  39  * there can only be single outstanding transaction from the host at any
  40  * given point in time. We use this to simplify memory management in this
  41  * driver - we cache and process only one message at a time.
  42  *
  43  * While the request/response protocol is guaranteed by the host, we further
  44  * ensure this by serializing packet processing in this driver - we do not
  45  * read additional packets from the VMBUs until the current packet is fully
  46  * handled.
  47  */
  48
  49 static struct {
  50         int state;   /* hvutil_device_state */
  51         int recv_len; /* number of bytes received. */
  52         struct hv_fcopy_hdr  *fcopy_msg; /* current message */
  53         struct vmbus_channel *recv_channel; /* chn we got the request */
  54         u64 recv_req_id; /* request ID. */
  55 } fcopy_transaction;
  56
  57 static void fcopy_respond_to_host(int error);
  58 static void fcopy_send_data(struct work_struct *dummy);
  59 static void fcopy_timeout_func(struct work_struct *dummy);
  60 static DECLARE_DELAYED_WORK(fcopy_timeout_work, fcopy_timeout_func);
  61 static DECLARE_WORK(fcopy_send_work, fcopy_send_data);
  62 static const char fcopy_devname[] = "vmbus/hv_fcopy";
  63 static u8 *recv_buffer;
  64 static struct hvutil_transport *hvt;
  65 /*
  66  * This state maintains the version number registered by the daemon.
  67  */
  68 static int dm_reg_value;
  69
  70 static void fcopy_poll_wrapper(void *channel)
  71 {
  72         /* Transaction is finished, reset the state here to avoid races. */
  73         fcopy_transaction.state = HVUTIL_READY;
  74         tasklet_schedule(&((struct vmbus_channel *)channel)->callback_event);
  75 }
  76
  77 static void fcopy_timeout_func(struct work_struct *dummy)
  78 {
  79         /*
  80          * If the timer fires, the user-mode component has not responded;
  81          * process the pending transaction.
  82          */
  83         fcopy_respond_to_host(HV_E_FAIL);
  84         hv_poll_channel(fcopy_transaction.recv_channel, fcopy_poll_wrapper);
  85 }
  86
  87 static void fcopy_register_done(void)
  88 {
  89         pr_debug("FCP: userspace daemon registered\n");
  90         hv_poll_channel(fcopy_transaction.recv_channel, fcopy_poll_wrapper);
  91 }
  92
  93 static int fcopy_handle_handshake(u32 version)
  94 {
  95         u32 our_ver = FCOPY_CURRENT_VERSION;
  96
  97         switch (version) {
  98         case FCOPY_VERSION_0:
  99                 /* Daemon doesn't expect us to reply */
 100                 dm_reg_value = version;
 101                 break;
 102         case FCOPY_VERSION_1:
 103                 /* Daemon expects us to reply with our own version */
 104                 if (hvutil_transport_send(hvt, &our_ver, sizeof(our_ver),
 105                     fcopy_register_done))
 106                         return -EFAULT;
 107                 dm_reg_value = version;
 108                 break;
 109         default:
 110                 /*
 111                  * For now we will fail the registration.
 112                  * If and when we have multiple versions to
 113                  * deal with, we will be backward compatible.
 114                  * We will add this code when needed.
 115                  */
 116                 return -EINVAL;
 117         }
 118         pr_debug("FCP: userspace daemon ver. %d connected\n", version);
 119         return 0;
 120 }
 121
 122 static void fcopy_send_data(struct work_struct *dummy)
 123 {
 124         struct hv_start_fcopy *smsg_out = NULL;
 125         int operation = fcopy_transaction.fcopy_msg->operation;
 126         struct hv_start_fcopy *smsg_in;
 127         void *out_src;
 128         int rc, out_len;
 129
 130         /*
 131          * The  strings sent from the host are encoded in
 132          * in utf16; convert it to utf8 strings.
 133          * The host assures us that the utf16 strings will not exceed
 134          * the max lengths specified. We will however, reserve room
 135          * for the string terminating character - in the utf16s_utf8s()
 136          * function we limit the size of the buffer where the converted
 137          * string is placed to W_MAX_PATH -1 to guarantee
 138          * that the strings can be properly terminated!
 139          */
 140
 141         switch (operation) {
 142         case START_FILE_COPY:
 143                 out_len = sizeof(struct hv_start_fcopy);
 144                 smsg_out = kzalloc(sizeof(*smsg_out), GFP_KERNEL);
 145                 if (!smsg_out)
 146                         return;
 147
 148                 smsg_out->hdr.operation = operation;
 149                 smsg_in = (struct hv_start_fcopy *)fcopy_transaction.fcopy_msg;
 150
 151                 utf16s_to_utf8s((wchar_t *)smsg_in->file_name, W_MAX_PATH,
 152                                 UTF16_LITTLE_ENDIAN,
 153                                 (__u8 *)&smsg_out->file_name, W_MAX_PATH - 1);
 154
 155                 utf16s_to_utf8s((wchar_t *)smsg_in->path_name, W_MAX_PATH,
 156                                 UTF16_LITTLE_ENDIAN,
 157                                 (__u8 *)&smsg_out->path_name, W_MAX_PATH - 1);
 158
 159                 smsg_out->copy_flags = smsg_in->copy_flags;
 160                 smsg_out->file_size = smsg_in->file_size;
 161                 out_src = smsg_out;
 162                 break;
 163
 164         case WRITE_TO_FILE:
 165                 out_src = fcopy_transaction.fcopy_msg;
 166                 out_len = sizeof(struct hv_do_fcopy);
 167                 break;
 168         default:
 169                 out_src = fcopy_transaction.fcopy_msg;
 170                 out_len = fcopy_transaction.recv_len;
 171                 break;
 172         }
 173
 174         fcopy_transaction.state = HVUTIL_USERSPACE_REQ;
 175         rc = hvutil_transport_send(hvt, out_src, out_len, NULL);
 176         if (rc) {
 177                 pr_debug("FCP: failed to communicate to the daemon: %d\n", rc);
 178                 if (cancel_delayed_work_sync(&fcopy_timeout_work)) {
 179                         fcopy_respond_to_host(HV_E_FAIL);
 180                         fcopy_transaction.state = HVUTIL_READY;
 181                 }
 182         }
 183         kfree(smsg_out);
 184 }
 185
 186 /*
 187  * Send a response back to the host.
 188  */
 189
 190 static void
 191 fcopy_respond_to_host(int error)
 192 {
 193         struct icmsg_hdr *icmsghdr;
 194         u32 buf_len;
 195         struct vmbus_channel *channel;
 196         u64 req_id;
 197
 198         /*
 199          * Copy the global state for completing the transaction. Note that
 200          * only one transaction can be active at a time. This is guaranteed
 201          * by the file copy protocol implemented by the host. Furthermore,
 202          * the "transaction active" state we maintain ensures that there can
 203          * only be one active transaction at a time.
 204          */
 205
 206         buf_len = fcopy_transaction.recv_len;
 207         channel = fcopy_transaction.recv_channel;
 208         req_id = fcopy_transaction.recv_req_id;
 209
 210         icmsghdr = (struct icmsg_hdr *)
 211                         &recv_buffer[sizeof(struct vmbuspipe_hdr)];
 212
 213         if (channel->onchannel_callback == NULL)
 214                 /*
 215                  * We have raced with util driver being unloaded;
 216                  * silently return.
 217                  */
 218                 return;
 219
 220         icmsghdr->status = error;
 221         icmsghdr->icflags = ICMSGHDRFLAG_TRANSACTION | ICMSGHDRFLAG_RESPONSE;
 222         vmbus_sendpacket(channel, recv_buffer, buf_len, req_id,
 223                                 VM_PKT_DATA_INBAND, 0);
 224 }
 225
 226 void hv_fcopy_onchannelcallback(void *context)
 227 {
 228         struct vmbus_channel *channel = context;
 229         u32 recvlen;
 230         u64 requestid;
 231         struct hv_fcopy_hdr *fcopy_msg;
 232         struct icmsg_hdr *icmsghdr;
 233         int fcopy_srv_version;
 234
 235         if (fcopy_transaction.state > HVUTIL_READY)
 236                 return;
 237
 238         vmbus_recvpacket(channel, recv_buffer, HV_HYP_PAGE_SIZE * 2, &recvlen,
 239                          &requestid);
 240         if (recvlen <= 0)
 241                 return;
 242
 243         icmsghdr = (struct icmsg_hdr *)&recv_buffer[
 244                         sizeof(struct vmbuspipe_hdr)];
 245         if (icmsghdr->icmsgtype == ICMSGTYPE_NEGOTIATE) {
 246                 if (vmbus_prep_negotiate_resp(icmsghdr, recv_buffer,
 247                                 fw_versions, FW_VER_COUNT,
 248                                 fcopy_versions, FCOPY_VER_COUNT,
 249                                 NULL, &fcopy_srv_version)) {
 250
 251                         pr_info("FCopy IC version %d.%d\n",
 252                                 fcopy_srv_version >> 16,
 253                                 fcopy_srv_version & 0xFFFF);
 254                 }
 255         } else {
 256                 fcopy_msg = (struct hv_fcopy_hdr *)&recv_buffer[
 257                                 sizeof(struct vmbuspipe_hdr) +
 258                                 sizeof(struct icmsg_hdr)];
 259
 260                 /*
 261                  * Stash away this global state for completing the
 262                  * transaction; note transactions are serialized.
 263                  */
 264
 265                 fcopy_transaction.recv_len = recvlen;
 266                 fcopy_transaction.recv_req_id = requestid;
 267                 fcopy_transaction.fcopy_msg = fcopy_msg;
 268
 269                 if (fcopy_transaction.state < HVUTIL_READY) {
 270                         /* Userspace is not registered yet */
 271                         fcopy_respond_to_host(HV_E_FAIL);
 272                         return;
 273                 }
 274                 fcopy_transaction.state = HVUTIL_HOSTMSG_RECEIVED;
 275
 276                 /*
 277                  * Send the information to the user-level daemon.
 278                  */
 279                 schedule_work(&fcopy_send_work);
 280                 schedule_delayed_work(&fcopy_timeout_work,
 281                                       HV_UTIL_TIMEOUT * HZ);
 282                 return;
 283         }
 284         icmsghdr->icflags = ICMSGHDRFLAG_TRANSACTION | ICMSGHDRFLAG_RESPONSE;
 285         vmbus_sendpacket(channel, recv_buffer, recvlen, requestid,
 286                         VM_PKT_DATA_INBAND, 0);
 287 }
 288
 289 /* Callback when data is received from userspace */
 290 static int fcopy_on_msg(void *msg, int len)
 291 {
 292         int *val = (int *)msg;
 293
 294         if (len != sizeof(int))
 295                 return -EINVAL;
 296
 297         if (fcopy_transaction.state == HVUTIL_DEVICE_INIT)
 298                 return fcopy_handle_handshake(*val);
 299
 300         if (fcopy_transaction.state != HVUTIL_USERSPACE_REQ)
 301                 return -EINVAL;
 302
 303         /*
 304          * Complete the transaction by forwarding the result
 305          * to the host. But first, cancel the timeout.
 306          */
 307         if (cancel_delayed_work_sync(&fcopy_timeout_work)) {
 308                 fcopy_transaction.state = HVUTIL_USERSPACE_RECV;
 309                 fcopy_respond_to_host(*val);
 310                 hv_poll_channel(fcopy_transaction.recv_channel,
 311                                 fcopy_poll_wrapper);
 312         }
 313
 314         return 0;
 315 }
 316
 317 static void fcopy_on_reset(void)
 318 {
 319         /*
 320          * The daemon has exited; reset the state.
 321          */
 322         fcopy_transaction.state = HVUTIL_DEVICE_INIT;
 323
 324         if (cancel_delayed_work_sync(&fcopy_timeout_work))
 325                 fcopy_respond_to_host(HV_E_FAIL);
 326 }
 327
 328 int hv_fcopy_init(struct hv_util_service *srv)
 329 {
 330         recv_buffer = srv->recv_buffer;
 331         fcopy_transaction.recv_channel = srv->channel;
 332
 333         /*
 334          * When this driver loads, the user level daemon that
 335          * processes the host requests may not yet be running.
 336          * Defer processing channel callbacks until the daemon
 337          * has registered.
 338          */
 339         fcopy_transaction.state = HVUTIL_DEVICE_INIT;
 340
 341         hvt = hvutil_transport_init(fcopy_devname, 0, 0,
 342                                     fcopy_on_msg, fcopy_on_reset);
 343         if (!hvt)
 344                 return -EFAULT;
 345
 346         return 0;
 347 }
 348
 349 static void hv_fcopy_cancel_work(void)
 350 {
 351         cancel_delayed_work_sync(&fcopy_timeout_work);
 352         cancel_work_sync(&fcopy_send_work);
 353 }
 354
 355 int hv_fcopy_pre_suspend(void)
 356 {
 357         struct vmbus_channel *channel = fcopy_transaction.recv_channel;
 358         struct hv_fcopy_hdr *fcopy_msg;
 359
 360         /*
 361          * Fake a CANCEL_FCOPY message for the user space daemon in case the
 362          * daemon is in the middle of copying some file. It doesn't matter if
 363          * there is already a message pending to be delivered to the user
 364          * space since we force fcopy_transaction.state to be HVUTIL_READY, so
 365          * the user space daemon's write() will fail with EINVAL (see
 366          * fcopy_on_msg()), and the daemon will reset the device by closing
 367          * and re-opening it.
 368          */
 369         fcopy_msg = kzalloc(sizeof(*fcopy_msg), GFP_KERNEL);
 370         if (!fcopy_msg)
 371                 return -ENOMEM;
 372
 373         tasklet_disable(&channel->callback_event);
 374
 375         fcopy_msg->operation = CANCEL_FCOPY;
 376
 377         hv_fcopy_cancel_work();
 378
 379         /* We don't care about the return value. */
 380         hvutil_transport_send(hvt, fcopy_msg, sizeof(*fcopy_msg), NULL);
 381
 382         kfree(fcopy_msg);
 383
 384         fcopy_transaction.state = HVUTIL_READY;
 385
 386         /* tasklet_enable() will be called in hv_fcopy_pre_resume(). */
 387         return 0;
 388 }
 389
 390 int hv_fcopy_pre_resume(void)
 391 {
 392         struct vmbus_channel *channel = fcopy_transaction.recv_channel;
 393
 394         tasklet_enable(&channel->callback_event);
 395
 396         return 0;
 397 }
 398
 399 void hv_fcopy_deinit(void)
 400 {
 401         fcopy_transaction.state = HVUTIL_DEVICE_DYING;
 402
 403         hv_fcopy_cancel_work();
 404
 405         hvutil_transport_destroy(hvt);
 406 }