drivers/hv/hv_fcopy.c

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