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 /*
  35  * Global state maintained for transaction that is being processed.
  36  * For a class of integration services, including the "file copy service",
  37  * the specified protocol is a "request/response" protocol which means that
  38  * there can only be single outstanding transaction from the host at any
  39  * given point in time. We use this to simplify memory management in this
  40  * driver - we cache and process only one message at a time.
  41  *
  42  * While the request/response protocol is guaranteed by the host, we further
  43  * ensure this by serializing packet processing in this driver - we do not
  44  * read additional packets from the VMBUs until the current packet is fully
  45  * handled.
  46  */
  47
  48 static struct {
  49         int state;   /* hvutil_device_state */
  50         int recv_len; /* number of bytes received. */
  51         struct hv_fcopy_hdr  *fcopy_msg; /* current message */
  52         struct vmbus_channel *recv_channel; /* chn we got the request */
  53         u64 recv_req_id; /* request ID. */
  54         void *fcopy_context; /* for the channel callback */
  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_timeout_func(struct work_struct *dummy)
  71 {
  72         /*
  73          * If the timer fires, the user-mode component has not responded;
  74          * process the pending transaction.
  75          */
  76         fcopy_respond_to_host(HV_E_FAIL);
  77
  78         /* Transaction is finished, reset the state. */
  79         if (fcopy_transaction.state > HVUTIL_READY)
  80                 fcopy_transaction.state = HVUTIL_READY;
  81
  82         hv_poll_channel(fcopy_transaction.fcopy_context,
  83                         hv_fcopy_onchannelcallback);
  84 }
  85
  86 static int fcopy_handle_handshake(u32 version)
  87 {
  88         u32 our_ver = FCOPY_CURRENT_VERSION;
  89
  90         switch (version) {
  91         case FCOPY_VERSION_0:
  92                 /* Daemon doesn't expect us to reply */
  93                 dm_reg_value = version;
  94                 break;
  95         case FCOPY_VERSION_1:
  96                 /* Daemon expects us to reply with our own version */
  97                 if (hvutil_transport_send(hvt, &our_ver, sizeof(our_ver)))
  98                         return -EFAULT;
  99                 dm_reg_value = version;
 100                 break;
 101         default:
 102                 /*
 103                  * For now we will fail the registration.
 104                  * If and when we have multiple versions to
 105                  * deal with, we will be backward compatible.
 106                  * We will add this code when needed.
 107                  */
 108                 return -EINVAL;
 109         }
 110         pr_debug("FCP: userspace daemon ver. %d registered\n", version);
 111         fcopy_transaction.state = HVUTIL_READY;
 112         hv_poll_channel(fcopy_transaction.fcopy_context,
 113                         hv_fcopy_onchannelcallback);
 114         return 0;
 115 }
 116
 117 static void fcopy_send_data(struct work_struct *dummy)
 118 {
 119         struct hv_start_fcopy smsg_out;
 120         int operation = fcopy_transaction.fcopy_msg->operation;
 121         struct hv_start_fcopy *smsg_in;
 122         void *out_src;
 123         int rc, out_len;
 124
 125         /*
 126          * The  strings sent from the host are encoded in
 127          * in utf16; convert it to utf8 strings.
 128          * The host assures us that the utf16 strings will not exceed
 129          * the max lengths specified. We will however, reserve room
 130          * for the string terminating character - in the utf16s_utf8s()
 131          * function we limit the size of the buffer where the converted
 132          * string is placed to W_MAX_PATH -1 to guarantee
 133          * that the strings can be properly terminated!
 134          */
 135
 136         switch (operation) {
 137         case START_FILE_COPY:
 138                 out_len = sizeof(struct hv_start_fcopy);
 139                 memset(&smsg_out, 0, out_len);
 140                 smsg_out.hdr.operation = operation;
 141                 smsg_in = (struct hv_start_fcopy *)fcopy_transaction.fcopy_msg;
 142
 143                 utf16s_to_utf8s((wchar_t *)smsg_in->file_name, W_MAX_PATH,
 144                                 UTF16_LITTLE_ENDIAN,
 145                                 (__u8 *)&smsg_out.file_name, W_MAX_PATH - 1);
 146
 147                 utf16s_to_utf8s((wchar_t *)smsg_in->path_name, W_MAX_PATH,
 148                                 UTF16_LITTLE_ENDIAN,
 149                                 (__u8 *)&smsg_out.path_name, W_MAX_PATH - 1);
 150
 151                 smsg_out.copy_flags = smsg_in->copy_flags;
 152                 smsg_out.file_size = smsg_in->file_size;
 153                 out_src = &smsg_out;
 154                 break;
 155
 156         default:
 157                 out_src = fcopy_transaction.fcopy_msg;
 158                 out_len = fcopy_transaction.recv_len;
 159                 break;
 160         }
 161
 162         fcopy_transaction.state = HVUTIL_USERSPACE_REQ;
 163         rc = hvutil_transport_send(hvt, out_src, out_len);
 164         if (rc) {
 165                 pr_debug("FCP: failed to communicate to the daemon: %d\n", rc);
 166                 if (cancel_delayed_work_sync(&fcopy_timeout_work)) {
 167                         fcopy_respond_to_host(HV_E_FAIL);
 168                         fcopy_transaction.state = HVUTIL_READY;
 169                 }
 170         }
 171         return;
 172 }
 173
 174 /*
 175  * Send a response back to the host.
 176  */
 177
 178 static void
 179 fcopy_respond_to_host(int error)
 180 {
 181         struct icmsg_hdr *icmsghdr;
 182         u32 buf_len;
 183         struct vmbus_channel *channel;
 184         u64 req_id;
 185
 186         /*
 187          * Copy the global state for completing the transaction. Note that
 188          * only one transaction can be active at a time. This is guaranteed
 189          * by the file copy protocol implemented by the host. Furthermore,
 190          * the "transaction active" state we maintain ensures that there can
 191          * only be one active transaction at a time.
 192          */
 193
 194         buf_len = fcopy_transaction.recv_len;
 195         channel = fcopy_transaction.recv_channel;
 196         req_id = fcopy_transaction.recv_req_id;
 197
 198         icmsghdr = (struct icmsg_hdr *)
 199                         &recv_buffer[sizeof(struct vmbuspipe_hdr)];
 200
 201         if (channel->onchannel_callback == NULL)
 202                 /*
 203                  * We have raced with util driver being unloaded;
 204                  * silently return.
 205                  */
 206                 return;
 207
 208         icmsghdr->status = error;
 209         icmsghdr->icflags = ICMSGHDRFLAG_TRANSACTION | ICMSGHDRFLAG_RESPONSE;
 210         vmbus_sendpacket(channel, recv_buffer, buf_len, req_id,
 211                                 VM_PKT_DATA_INBAND, 0);
 212 }
 213
 214 void hv_fcopy_onchannelcallback(void *context)
 215 {
 216         struct vmbus_channel *channel = context;
 217         u32 recvlen;
 218         u64 requestid;
 219         struct hv_fcopy_hdr *fcopy_msg;
 220         struct icmsg_hdr *icmsghdr;
 221         struct icmsg_negotiate *negop = NULL;
 222         int util_fw_version;
 223         int fcopy_srv_version;
 224
 225         if (fcopy_transaction.state > HVUTIL_READY) {
 226                 /*
 227                  * We will defer processing this callback once
 228                  * the current transaction is complete.
 229                  */
 230                 fcopy_transaction.fcopy_context = context;
 231                 return;
 232         }
 233         fcopy_transaction.fcopy_context = NULL;
 234
 235         vmbus_recvpacket(channel, recv_buffer, PAGE_SIZE * 2, &recvlen,
 236                          &requestid);
 237         if (recvlen <= 0)
 238                 return;
 239
 240         icmsghdr = (struct icmsg_hdr *)&recv_buffer[
 241                         sizeof(struct vmbuspipe_hdr)];
 242         if (icmsghdr->icmsgtype == ICMSGTYPE_NEGOTIATE) {
 243                 util_fw_version = UTIL_FW_VERSION;
 244                 fcopy_srv_version = WIN8_SRV_VERSION;
 245                 vmbus_prep_negotiate_resp(icmsghdr, negop, recv_buffer,
 246                                 util_fw_version, fcopy_srv_version);
 247         } else {
 248                 fcopy_msg = (struct hv_fcopy_hdr *)&recv_buffer[
 249                                 sizeof(struct vmbuspipe_hdr) +
 250                                 sizeof(struct icmsg_hdr)];
 251
 252                 /*
 253                  * Stash away this global state for completing the
 254                  * transaction; note transactions are serialized.
 255                  */
 256
 257                 fcopy_transaction.recv_len = recvlen;
 258                 fcopy_transaction.recv_channel = channel;
 259                 fcopy_transaction.recv_req_id = requestid;
 260                 fcopy_transaction.fcopy_msg = fcopy_msg;
 261
 262                 if (fcopy_transaction.state < HVUTIL_READY) {
 263                         /* Userspace is not registered yet */
 264                         fcopy_respond_to_host(HV_E_FAIL);
 265                         return;
 266                 }
 267                 fcopy_transaction.state = HVUTIL_HOSTMSG_RECEIVED;
 268
 269                 /*
 270                  * Send the information to the user-level daemon.
 271                  */
 272                 schedule_work(&fcopy_send_work);
 273                 schedule_delayed_work(&fcopy_timeout_work, 5*HZ);
 274                 return;
 275         }
 276         icmsghdr->icflags = ICMSGHDRFLAG_TRANSACTION | ICMSGHDRFLAG_RESPONSE;
 277         vmbus_sendpacket(channel, recv_buffer, recvlen, requestid,
 278                         VM_PKT_DATA_INBAND, 0);
 279 }
 280
 281 /* Callback when data is received from userspace */
 282 static int fcopy_on_msg(void *msg, int len)
 283 {
 284         int *val = (int *)msg;
 285
 286         if (len != sizeof(int))
 287                 return -EINVAL;
 288
 289         if (fcopy_transaction.state == HVUTIL_DEVICE_INIT)
 290                 return fcopy_handle_handshake(*val);
 291
 292         if (fcopy_transaction.state != HVUTIL_USERSPACE_REQ)
 293                 return -EINVAL;
 294
 295         /*
 296          * Complete the transaction by forwarding the result
 297          * to the host. But first, cancel the timeout.
 298          */
 299         if (cancel_delayed_work_sync(&fcopy_timeout_work)) {
 300                 fcopy_transaction.state = HVUTIL_USERSPACE_RECV;
 301                 fcopy_respond_to_host(*val);
 302                 fcopy_transaction.state = HVUTIL_READY;
 303                 hv_poll_channel(fcopy_transaction.fcopy_context,
 304                                 hv_fcopy_onchannelcallback);
 305         }
 306
 307         return 0;
 308 }
 309
 310 static void fcopy_on_reset(void)
 311 {
 312         /*
 313          * The daemon has exited; reset the state.
 314          */
 315         fcopy_transaction.state = HVUTIL_DEVICE_INIT;
 316
 317         if (cancel_delayed_work_sync(&fcopy_timeout_work))
 318                 fcopy_respond_to_host(HV_E_FAIL);
 319 }
 320
 321 int hv_fcopy_init(struct hv_util_service *srv)
 322 {
 323         recv_buffer = srv->recv_buffer;
 324
 325         /*
 326          * When this driver loads, the user level daemon that
 327          * processes the host requests may not yet be running.
 328          * Defer processing channel callbacks until the daemon
 329          * has registered.
 330          */
 331         fcopy_transaction.state = HVUTIL_DEVICE_INIT;
 332
 333         hvt = hvutil_transport_init(fcopy_devname, 0, 0,
 334                                     fcopy_on_msg, fcopy_on_reset);
 335         if (!hvt)
 336                 return -EFAULT;
 337
 338         return 0;
 339 }
 340
 341 void hv_fcopy_deinit(void)
 342 {
 343         fcopy_transaction.state = HVUTIL_DEVICE_DYING;
 344         cancel_delayed_work_sync(&fcopy_timeout_work);
 345         hvutil_transport_destroy(hvt);
 346 }