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 /*
  75  * This state maintains the version number registered by the daemon.
  76  */
  77 static int dm_reg_value;
  78
  79 static void fcopy_poll_wrapper(void *channel)
  80 {
  81         /* Transaction is finished, reset the state here to avoid races. */
  82         fcopy_transaction.state = HVUTIL_READY;
  83         hv_fcopy_onchannelcallback(channel);
  84 }
  85
  86 static void fcopy_timeout_func(struct work_struct *dummy)
  87 {
  88         /*
  89          * If the timer fires, the user-mode component has not responded;
  90          * process the pending transaction.
  91          */
  92         fcopy_respond_to_host(HV_E_FAIL);
  93         hv_poll_channel(fcopy_transaction.recv_channel, fcopy_poll_wrapper);
  94 }
  95
  96 static void fcopy_register_done(void)
  97 {
  98         pr_debug("FCP: userspace daemon registered\n");
  99         hv_poll_channel(fcopy_transaction.recv_channel, fcopy_poll_wrapper);
 100 }
 101
 102 static int fcopy_handle_handshake(u32 version)
 103 {
 104         u32 our_ver = FCOPY_CURRENT_VERSION;
 105
 106         switch (version) {
 107         case FCOPY_VERSION_0:
 108                 /* Daemon doesn't expect us to reply */
 109                 dm_reg_value = version;
 110                 break;
 111         case FCOPY_VERSION_1:
 112                 /* Daemon expects us to reply with our own version */
 113                 if (hvutil_transport_send(hvt, &our_ver, sizeof(our_ver),
 114                     fcopy_register_done))
 115                         return -EFAULT;
 116                 dm_reg_value = version;
 117                 break;
 118         default:
 119                 /*
 120                  * For now we will fail the registration.
 121                  * If and when we have multiple versions to
 122                  * deal with, we will be backward compatible.
 123                  * We will add this code when needed.
 124                  */
 125                 return -EINVAL;
 126         }
 127         pr_debug("FCP: userspace daemon ver. %d connected\n", version);
 128         return 0;
 129 }
 130
 131 static void fcopy_send_data(struct work_struct *dummy)
 132 {
 133         struct hv_start_fcopy *smsg_out = NULL;
 134         int operation = fcopy_transaction.fcopy_msg->operation;
 135         struct hv_start_fcopy *smsg_in;
 136         void *out_src;
 137         int rc, out_len;
 138
 139         /*
 140          * The  strings sent from the host are encoded in
 141          * in utf16; convert it to utf8 strings.
 142          * The host assures us that the utf16 strings will not exceed
 143          * the max lengths specified. We will however, reserve room
 144          * for the string terminating character - in the utf16s_utf8s()
 145          * function we limit the size of the buffer where the converted
 146          * string is placed to W_MAX_PATH -1 to guarantee
 147          * that the strings can be properly terminated!
 148          */
 149
 150         switch (operation) {
 151         case START_FILE_COPY:
 152                 out_len = sizeof(struct hv_start_fcopy);
 153                 smsg_out = kzalloc(sizeof(*smsg_out), GFP_KERNEL);
 154                 if (!smsg_out)
 155                         return;
 156
 157                 smsg_out->hdr.operation = operation;
 158                 smsg_in = (struct hv_start_fcopy *)fcopy_transaction.fcopy_msg;
 159
 160                 utf16s_to_utf8s((wchar_t *)smsg_in->file_name, W_MAX_PATH,
 161                                 UTF16_LITTLE_ENDIAN,
 162                                 (__u8 *)&smsg_out->file_name, W_MAX_PATH - 1);
 163
 164                 utf16s_to_utf8s((wchar_t *)smsg_in->path_name, W_MAX_PATH,
 165                                 UTF16_LITTLE_ENDIAN,
 166                                 (__u8 *)&smsg_out->path_name, W_MAX_PATH - 1);
 167
 168                 smsg_out->copy_flags = smsg_in->copy_flags;
 169                 smsg_out->file_size = smsg_in->file_size;
 170                 out_src = smsg_out;
 171                 break;
 172
 173         default:
 174                 out_src = fcopy_transaction.fcopy_msg;
 175                 out_len = fcopy_transaction.recv_len;
 176                 break;
 177         }
 178
 179         fcopy_transaction.state = HVUTIL_USERSPACE_REQ;
 180         rc = hvutil_transport_send(hvt, out_src, out_len, NULL);
 181         if (rc) {
 182                 pr_debug("FCP: failed to communicate to the daemon: %d\n", rc);
 183                 if (cancel_delayed_work_sync(&fcopy_timeout_work)) {
 184                         fcopy_respond_to_host(HV_E_FAIL);
 185                         fcopy_transaction.state = HVUTIL_READY;
 186                 }
 187         }
 188         kfree(smsg_out);
 189
 190         return;
 191 }
 192
 193 /*
 194  * Send a response back to the host.
 195  */
 196
 197 static void
 198 fcopy_respond_to_host(int error)
 199 {
 200         struct icmsg_hdr *icmsghdr;
 201         u32 buf_len;
 202         struct vmbus_channel *channel;
 203         u64 req_id;
 204
 205         /*
 206          * Copy the global state for completing the transaction. Note that
 207          * only one transaction can be active at a time. This is guaranteed
 208          * by the file copy protocol implemented by the host. Furthermore,
 209          * the "transaction active" state we maintain ensures that there can
 210          * only be one active transaction at a time.
 211          */
 212
 213         buf_len = fcopy_transaction.recv_len;
 214         channel = fcopy_transaction.recv_channel;
 215         req_id = fcopy_transaction.recv_req_id;
 216
 217         icmsghdr = (struct icmsg_hdr *)
 218                         &recv_buffer[sizeof(struct vmbuspipe_hdr)];
 219
 220         if (channel->onchannel_callback == NULL)
 221                 /*
 222                  * We have raced with util driver being unloaded;
 223                  * silently return.
 224                  */
 225                 return;
 226
 227         icmsghdr->status = error;
 228         icmsghdr->icflags = ICMSGHDRFLAG_TRANSACTION | ICMSGHDRFLAG_RESPONSE;
 229         vmbus_sendpacket(channel, recv_buffer, buf_len, req_id,
 230                                 VM_PKT_DATA_INBAND, 0);
 231 }
 232
 233 void hv_fcopy_onchannelcallback(void *context)
 234 {
 235         struct vmbus_channel *channel = context;
 236         u32 recvlen;
 237         u64 requestid;
 238         struct hv_fcopy_hdr *fcopy_msg;
 239         struct icmsg_hdr *icmsghdr;
 240         int fcopy_srv_version;
 241
 242         if (fcopy_transaction.state > HVUTIL_READY)
 243                 return;
 244
 245         vmbus_recvpacket(channel, recv_buffer, PAGE_SIZE * 2, &recvlen,
 246                          &requestid);
 247         if (recvlen <= 0)
 248                 return;
 249
 250         icmsghdr = (struct icmsg_hdr *)&recv_buffer[
 251                         sizeof(struct vmbuspipe_hdr)];
 252         if (icmsghdr->icmsgtype == ICMSGTYPE_NEGOTIATE) {
 253                 if (vmbus_prep_negotiate_resp(icmsghdr, recv_buffer,
 254                                 fw_versions, FW_VER_COUNT,
 255                                 fcopy_versions, FCOPY_VER_COUNT,
 256                                 NULL, &fcopy_srv_version)) {
 257
 258                         pr_info("FCopy IC version %d.%d\n",
 259                                 fcopy_srv_version >> 16,
 260                                 fcopy_srv_version & 0xFFFF);
 261                 }
 262         } else {
 263                 fcopy_msg = (struct hv_fcopy_hdr *)&recv_buffer[
 264                                 sizeof(struct vmbuspipe_hdr) +
 265                                 sizeof(struct icmsg_hdr)];
 266
 267                 /*
 268                  * Stash away this global state for completing the
 269                  * transaction; note transactions are serialized.
 270                  */
 271
 272                 fcopy_transaction.recv_len = recvlen;
 273                 fcopy_transaction.recv_req_id = requestid;
 274                 fcopy_transaction.fcopy_msg = fcopy_msg;
 275
 276                 if (fcopy_transaction.state < HVUTIL_READY) {
 277                         /* Userspace is not registered yet */
 278                         fcopy_respond_to_host(HV_E_FAIL);
 279                         return;
 280                 }
 281                 fcopy_transaction.state = HVUTIL_HOSTMSG_RECEIVED;
 282
 283                 /*
 284                  * Send the information to the user-level daemon.
 285                  */
 286                 schedule_work(&fcopy_send_work);
 287                 schedule_delayed_work(&fcopy_timeout_work,
 288                                       HV_UTIL_TIMEOUT * HZ);
 289                 return;
 290         }
 291         icmsghdr->icflags = ICMSGHDRFLAG_TRANSACTION | ICMSGHDRFLAG_RESPONSE;
 292         vmbus_sendpacket(channel, recv_buffer, recvlen, requestid,
 293                         VM_PKT_DATA_INBAND, 0);
 294 }
 295
 296 /* Callback when data is received from userspace */
 297 static int fcopy_on_msg(void *msg, int len)
 298 {
 299         int *val = (int *)msg;
 300
 301         if (len != sizeof(int))
 302                 return -EINVAL;
 303
 304         if (fcopy_transaction.state == HVUTIL_DEVICE_INIT)
 305                 return fcopy_handle_handshake(*val);
 306
 307         if (fcopy_transaction.state != HVUTIL_USERSPACE_REQ)
 308                 return -EINVAL;
 309
 310         /*
 311          * Complete the transaction by forwarding the result
 312          * to the host. But first, cancel the timeout.
 313          */
 314         if (cancel_delayed_work_sync(&fcopy_timeout_work)) {
 315                 fcopy_transaction.state = HVUTIL_USERSPACE_RECV;
 316                 fcopy_respond_to_host(*val);
 317                 hv_poll_channel(fcopy_transaction.recv_channel,
 318                                 fcopy_poll_wrapper);
 319         }
 320
 321         return 0;
 322 }
 323
 324 static void fcopy_on_reset(void)
 325 {
 326         /*
 327          * The daemon has exited; reset the state.
 328          */
 329         fcopy_transaction.state = HVUTIL_DEVICE_INIT;
 330
 331         if (cancel_delayed_work_sync(&fcopy_timeout_work))
 332                 fcopy_respond_to_host(HV_E_FAIL);
 333 }
 334
 335 int hv_fcopy_init(struct hv_util_service *srv)
 336 {
 337         recv_buffer = srv->recv_buffer;
 338         fcopy_transaction.recv_channel = srv->channel;
 339
 340         /*
 341          * When this driver loads, the user level daemon that
 342          * processes the host requests may not yet be running.
 343          * Defer processing channel callbacks until the daemon
 344          * has registered.
 345          */
 346         fcopy_transaction.state = HVUTIL_DEVICE_INIT;
 347
 348         hvt = hvutil_transport_init(fcopy_devname, 0, 0,
 349                                     fcopy_on_msg, fcopy_on_reset);
 350         if (!hvt)
 351                 return -EFAULT;
 352
 353         return 0;
 354 }
 355
 356 void hv_fcopy_deinit(void)
 357 {
 358         fcopy_transaction.state = HVUTIL_DEVICE_DYING;
 359         cancel_delayed_work_sync(&fcopy_timeout_work);
 360         hvutil_transport_destroy(hvt);
 361 }