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 } fcopy_transaction;
  55
  56 static void fcopy_respond_to_host(int error);
  57 static void fcopy_send_data(struct work_struct *dummy);
  58 static void fcopy_timeout_func(struct work_struct *dummy);
  59 static DECLARE_DELAYED_WORK(fcopy_timeout_work, fcopy_timeout_func);
  60 static DECLARE_WORK(fcopy_send_work, fcopy_send_data);
  61 static const char fcopy_devname[] = "vmbus/hv_fcopy";
  62 static u8 *recv_buffer;
  63 static struct hvutil_transport *hvt;
  64 static struct completion release_event;
  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         hv_fcopy_onchannelcallback(channel);
  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 int fcopy_handle_handshake(u32 version)
  88 {
  89         u32 our_ver = FCOPY_CURRENT_VERSION;
  90
  91         switch (version) {
  92         case FCOPY_VERSION_0:
  93                 /* Daemon doesn't expect us to reply */
  94                 dm_reg_value = version;
  95                 break;
  96         case FCOPY_VERSION_1:
  97                 /* Daemon expects us to reply with our own version */
  98                 if (hvutil_transport_send(hvt, &our_ver, sizeof(our_ver)))
  99                         return -EFAULT;
 100                 dm_reg_value = version;
 101                 break;
 102         default:
 103                 /*
 104                  * For now we will fail the registration.
 105                  * If and when we have multiple versions to
 106                  * deal with, we will be backward compatible.
 107                  * We will add this code when needed.
 108                  */
 109                 return -EINVAL;
 110         }
 111         pr_debug("FCP: userspace daemon ver. %d registered\n", version);
 112         hv_poll_channel(fcopy_transaction.recv_channel, fcopy_poll_wrapper);
 113         return 0;
 114 }
 115
 116 static void fcopy_send_data(struct work_struct *dummy)
 117 {
 118         struct hv_start_fcopy *smsg_out = NULL;
 119         int operation = fcopy_transaction.fcopy_msg->operation;
 120         struct hv_start_fcopy *smsg_in;
 121         void *out_src;
 122         int rc, out_len;
 123
 124         /*
 125          * The  strings sent from the host are encoded in
 126          * in utf16; convert it to utf8 strings.
 127          * The host assures us that the utf16 strings will not exceed
 128          * the max lengths specified. We will however, reserve room
 129          * for the string terminating character - in the utf16s_utf8s()
 130          * function we limit the size of the buffer where the converted
 131          * string is placed to W_MAX_PATH -1 to guarantee
 132          * that the strings can be properly terminated!
 133          */
 134
 135         switch (operation) {
 136         case START_FILE_COPY:
 137                 out_len = sizeof(struct hv_start_fcopy);
 138                 smsg_out = kzalloc(sizeof(*smsg_out), GFP_KERNEL);
 139                 if (!smsg_out)
 140                         return;
 141
 142                 smsg_out->hdr.operation = operation;
 143                 smsg_in = (struct hv_start_fcopy *)fcopy_transaction.fcopy_msg;
 144
 145                 utf16s_to_utf8s((wchar_t *)smsg_in->file_name, W_MAX_PATH,
 146                                 UTF16_LITTLE_ENDIAN,
 147                                 (__u8 *)&smsg_out->file_name, W_MAX_PATH - 1);
 148
 149                 utf16s_to_utf8s((wchar_t *)smsg_in->path_name, W_MAX_PATH,
 150                                 UTF16_LITTLE_ENDIAN,
 151                                 (__u8 *)&smsg_out->path_name, W_MAX_PATH - 1);
 152
 153                 smsg_out->copy_flags = smsg_in->copy_flags;
 154                 smsg_out->file_size = smsg_in->file_size;
 155                 out_src = smsg_out;
 156                 break;
 157
 158         default:
 159                 out_src = fcopy_transaction.fcopy_msg;
 160                 out_len = fcopy_transaction.recv_len;
 161                 break;
 162         }
 163
 164         fcopy_transaction.state = HVUTIL_USERSPACE_REQ;
 165         rc = hvutil_transport_send(hvt, out_src, out_len);
 166         if (rc) {
 167                 pr_debug("FCP: failed to communicate to the daemon: %d\n", rc);
 168                 if (cancel_delayed_work_sync(&fcopy_timeout_work)) {
 169                         fcopy_respond_to_host(HV_E_FAIL);
 170                         fcopy_transaction.state = HVUTIL_READY;
 171                 }
 172         }
 173         kfree(smsg_out);
 174
 175         return;
 176 }
 177
 178 /*
 179  * Send a response back to the host.
 180  */
 181
 182 static void
 183 fcopy_respond_to_host(int error)
 184 {
 185         struct icmsg_hdr *icmsghdr;
 186         u32 buf_len;
 187         struct vmbus_channel *channel;
 188         u64 req_id;
 189
 190         /*
 191          * Copy the global state for completing the transaction. Note that
 192          * only one transaction can be active at a time. This is guaranteed
 193          * by the file copy protocol implemented by the host. Furthermore,
 194          * the "transaction active" state we maintain ensures that there can
 195          * only be one active transaction at a time.
 196          */
 197
 198         buf_len = fcopy_transaction.recv_len;
 199         channel = fcopy_transaction.recv_channel;
 200         req_id = fcopy_transaction.recv_req_id;
 201
 202         icmsghdr = (struct icmsg_hdr *)
 203                         &recv_buffer[sizeof(struct vmbuspipe_hdr)];
 204
 205         if (channel->onchannel_callback == NULL)
 206                 /*
 207                  * We have raced with util driver being unloaded;
 208                  * silently return.
 209                  */
 210                 return;
 211
 212         icmsghdr->status = error;
 213         icmsghdr->icflags = ICMSGHDRFLAG_TRANSACTION | ICMSGHDRFLAG_RESPONSE;
 214         vmbus_sendpacket(channel, recv_buffer, buf_len, req_id,
 215                                 VM_PKT_DATA_INBAND, 0);
 216 }
 217
 218 void hv_fcopy_onchannelcallback(void *context)
 219 {
 220         struct vmbus_channel *channel = context;
 221         u32 recvlen;
 222         u64 requestid;
 223         struct hv_fcopy_hdr *fcopy_msg;
 224         struct icmsg_hdr *icmsghdr;
 225         struct icmsg_negotiate *negop = NULL;
 226         int util_fw_version;
 227         int fcopy_srv_version;
 228
 229         if (fcopy_transaction.state > HVUTIL_READY)
 230                 return;
 231
 232         vmbus_recvpacket(channel, recv_buffer, PAGE_SIZE * 2, &recvlen,
 233                          &requestid);
 234         if (recvlen <= 0)
 235                 return;
 236
 237         icmsghdr = (struct icmsg_hdr *)&recv_buffer[
 238                         sizeof(struct vmbuspipe_hdr)];
 239         if (icmsghdr->icmsgtype == ICMSGTYPE_NEGOTIATE) {
 240                 util_fw_version = UTIL_FW_VERSION;
 241                 fcopy_srv_version = WIN8_SRV_VERSION;
 242                 vmbus_prep_negotiate_resp(icmsghdr, negop, recv_buffer,
 243                                 util_fw_version, fcopy_srv_version);
 244         } else {
 245                 fcopy_msg = (struct hv_fcopy_hdr *)&recv_buffer[
 246                                 sizeof(struct vmbuspipe_hdr) +
 247                                 sizeof(struct icmsg_hdr)];
 248
 249                 /*
 250                  * Stash away this global state for completing the
 251                  * transaction; note transactions are serialized.
 252                  */
 253
 254                 fcopy_transaction.recv_len = recvlen;
 255                 fcopy_transaction.recv_channel = channel;
 256                 fcopy_transaction.recv_req_id = requestid;
 257                 fcopy_transaction.fcopy_msg = fcopy_msg;
 258
 259                 if (fcopy_transaction.state < HVUTIL_READY) {
 260                         /* Userspace is not registered yet */
 261                         fcopy_respond_to_host(HV_E_FAIL);
 262                         return;
 263                 }
 264                 fcopy_transaction.state = HVUTIL_HOSTMSG_RECEIVED;
 265
 266                 /*
 267                  * Send the information to the user-level daemon.
 268                  */
 269                 schedule_work(&fcopy_send_work);
 270                 schedule_delayed_work(&fcopy_timeout_work,
 271                                       HV_UTIL_TIMEOUT * HZ);
 272                 return;
 273         }
 274         icmsghdr->icflags = ICMSGHDRFLAG_TRANSACTION | ICMSGHDRFLAG_RESPONSE;
 275         vmbus_sendpacket(channel, recv_buffer, recvlen, requestid,
 276                         VM_PKT_DATA_INBAND, 0);
 277 }
 278
 279 /* Callback when data is received from userspace */
 280 static int fcopy_on_msg(void *msg, int len)
 281 {
 282         int *val = (int *)msg;
 283
 284         if (len != sizeof(int))
 285                 return -EINVAL;
 286
 287         if (fcopy_transaction.state == HVUTIL_DEVICE_INIT)
 288                 return fcopy_handle_handshake(*val);
 289
 290         if (fcopy_transaction.state != HVUTIL_USERSPACE_REQ)
 291                 return -EINVAL;
 292
 293         /*
 294          * Complete the transaction by forwarding the result
 295          * to the host. But first, cancel the timeout.
 296          */
 297         if (cancel_delayed_work_sync(&fcopy_timeout_work)) {
 298                 fcopy_transaction.state = HVUTIL_USERSPACE_RECV;
 299                 fcopy_respond_to_host(*val);
 300                 hv_poll_channel(fcopy_transaction.recv_channel,
 301                                 fcopy_poll_wrapper);
 302         }
 303
 304         return 0;
 305 }
 306
 307 static void fcopy_on_reset(void)
 308 {
 309         /*
 310          * The daemon has exited; reset the state.
 311          */
 312         fcopy_transaction.state = HVUTIL_DEVICE_INIT;
 313
 314         if (cancel_delayed_work_sync(&fcopy_timeout_work))
 315                 fcopy_respond_to_host(HV_E_FAIL);
 316         complete(&release_event);
 317 }
 318
 319 int hv_fcopy_init(struct hv_util_service *srv)
 320 {
 321         recv_buffer = srv->recv_buffer;
 322
 323         init_completion(&release_event);
 324         /*
 325          * When this driver loads, the user level daemon that
 326          * processes the host requests may not yet be running.
 327          * Defer processing channel callbacks until the daemon
 328          * has registered.
 329          */
 330         fcopy_transaction.state = HVUTIL_DEVICE_INIT;
 331
 332         hvt = hvutil_transport_init(fcopy_devname, 0, 0,
 333                                     fcopy_on_msg, fcopy_on_reset);
 334         if (!hvt)
 335                 return -EFAULT;
 336
 337         return 0;
 338 }
 339
 340 void hv_fcopy_deinit(void)
 341 {
 342         fcopy_transaction.state = HVUTIL_DEVICE_DYING;
 343         cancel_delayed_work_sync(&fcopy_timeout_work);
 344         hvutil_transport_destroy(hvt);
 345         wait_for_completion(&release_event);
 346 }