lib/power/guest_channel.c

   1 /* SPDX-License-Identifier: BSD-3-Clause
   2  * Copyright(c) 2010-2014 Intel Corporation
   3  */
   4
   5 #include <glob.h>
   6 #include <stdio.h>
   7 #include <stdlib.h>
   8 #include <unistd.h>
   9 #include <signal.h>
  10 #include <limits.h>
  11 #include <fcntl.h>
  12 #include <string.h>
  13 #include <errno.h>
  14 #include <poll.h>
  15
  16
  17 #include <rte_log.h>
  18 #include <rte_power.h>
  19
  20 #include "guest_channel.h"
  21
  22 #define RTE_LOGTYPE_GUEST_CHANNEL RTE_LOGTYPE_USER1
  23
  24 /* Timeout for incoming message in milliseconds. */
  25 #define TIMEOUT 10
  26
  27 static int global_fds[RTE_MAX_LCORE] = { [0 ... RTE_MAX_LCORE-1] = -1 };
  28
  29 int
  30 guest_channel_host_check_exists(const char *path)
  31 {
  32         char glob_path[PATH_MAX];
  33         glob_t g;
  34         int ret;
  35
  36         /* we cannot know in advance which cores have VM channels, so glob */
  37         snprintf(glob_path, PATH_MAX, "%s.*", path);
  38
  39         ret = glob(glob_path, GLOB_NOSORT, NULL, &g);
  40         if (ret != 0) {
  41                 /* couldn't read anything */
  42                 ret = 0;
  43                 goto out;
  44         }
  45
  46         /* do we have at least one match? */
  47         ret = g.gl_pathc > 0;
  48
  49 out:
  50         globfree(&g);
  51         return ret;
  52 }
  53
  54 int
  55 guest_channel_host_connect(const char *path, unsigned int lcore_id)
  56 {
  57         int flags, ret;
  58         struct rte_power_channel_packet pkt;
  59         char fd_path[PATH_MAX];
  60         int fd = -1;
  61
  62         if (lcore_id >= RTE_MAX_LCORE) {
  63                 RTE_LOG(ERR, GUEST_CHANNEL, "Channel(%u) is out of range 0...%d\n",
  64                                 lcore_id, RTE_MAX_LCORE-1);
  65                 return -1;
  66         }
  67         /* check if path is already open */
  68         if (global_fds[lcore_id] != -1) {
  69                 RTE_LOG(ERR, GUEST_CHANNEL, "Channel(%u) is already open with fd %d\n",
  70                                 lcore_id, global_fds[lcore_id]);
  71                 return -1;
  72         }
  73
  74         snprintf(fd_path, PATH_MAX, "%s.%u", path, lcore_id);
  75         RTE_LOG(INFO, GUEST_CHANNEL, "Opening channel '%s' for lcore %u\n",
  76                         fd_path, lcore_id);
  77         fd = open(fd_path, O_RDWR);
  78         if (fd < 0) {
  79                 RTE_LOG(ERR, GUEST_CHANNEL, "Unable to to connect to '%s' with error "
  80                                 "%s\n", fd_path, strerror(errno));
  81                 return -1;
  82         }
  83
  84         flags = fcntl(fd, F_GETFL, 0);
  85         if (flags < 0) {
  86                 RTE_LOG(ERR, GUEST_CHANNEL, "Failed on fcntl get flags for file %s\n",
  87                                 fd_path);
  88                 goto error;
  89         }
  90
  91         flags |= O_NONBLOCK;
  92         if (fcntl(fd, F_SETFL, flags) < 0) {
  93                 RTE_LOG(ERR, GUEST_CHANNEL, "Failed on setting non-blocking mode for "
  94                                 "file %s", fd_path);
  95                 goto error;
  96         }
  97         /* QEMU needs a delay after connection */
  98         sleep(1);
  99
 100         /* Send a test packet, this command is ignored by the host, but a successful
 101          * send indicates that the host endpoint is monitoring.
 102          */
 103         pkt.command = RTE_POWER_CPU_POWER_CONNECT;
 104         global_fds[lcore_id] = fd;
 105         ret = guest_channel_send_msg(&pkt, lcore_id);
 106         if (ret != 0) {
 107                 RTE_LOG(ERR, GUEST_CHANNEL,
 108                                 "Error on channel '%s' communications test: %s\n",
 109                                 fd_path, ret > 0 ? strerror(ret) :
 110                                 "channel not connected");
 111                 goto error;
 112         }
 113         RTE_LOG(INFO, GUEST_CHANNEL, "Channel '%s' is now connected\n", fd_path);
 114         return 0;
 115 error:
 116         close(fd);
 117         global_fds[lcore_id] = -1;
 118         return -1;
 119 }
 120
 121 int
 122 guest_channel_send_msg(struct rte_power_channel_packet *pkt,
 123                 unsigned int lcore_id)
 124 {
 125         int ret, buffer_len = sizeof(*pkt);
 126         void *buffer = pkt;
 127
 128         if (lcore_id >= RTE_MAX_LCORE) {
 129                 RTE_LOG(ERR, GUEST_CHANNEL, "Channel(%u) is out of range 0...%d\n",
 130                                 lcore_id, RTE_MAX_LCORE-1);
 131                 return -1;
 132         }
 133
 134         if (global_fds[lcore_id] < 0) {
 135                 RTE_LOG(ERR, GUEST_CHANNEL, "Channel is not connected\n");
 136                 return -1;
 137         }
 138         while (buffer_len > 0) {
 139                 ret = write(global_fds[lcore_id], buffer, buffer_len);
 140                 if (ret == buffer_len)
 141                         return 0;
 142                 if (ret == -1) {
 143                         if (errno == EINTR)
 144                                 continue;
 145                         return errno;
 146                 }
 147                 buffer = (char *)buffer + ret;
 148                 buffer_len -= ret;
 149         }
 150         return 0;
 151 }
 152
 153 int rte_power_guest_channel_send_msg(struct rte_power_channel_packet *pkt,
 154                         unsigned int lcore_id)
 155 {
 156         return guest_channel_send_msg(pkt, lcore_id);
 157 }
 158
 159 int power_guest_channel_read_msg(void *pkt,
 160                 size_t pkt_len,
 161                 unsigned int lcore_id)
 162 {
 163         int ret;
 164         struct pollfd fds;
 165
 166         if (pkt_len == 0 || pkt == NULL)
 167                 return -1;
 168
 169         fds.fd = global_fds[lcore_id];
 170         fds.events = POLLIN;
 171
 172         ret = poll(&fds, 1, TIMEOUT);
 173         if (ret == 0) {
 174                 RTE_LOG(DEBUG, GUEST_CHANNEL, "Timeout occurred during poll function.\n");
 175                 return -1;
 176         } else if (ret < 0) {
 177                 RTE_LOG(ERR, GUEST_CHANNEL, "Error occurred during poll function: %s\n",
 178                                 strerror(errno));
 179                 return -1;
 180         }
 181
 182         if (lcore_id >= RTE_MAX_LCORE) {
 183                 RTE_LOG(ERR, GUEST_CHANNEL, "Channel(%u) is out of range 0...%d\n",
 184                                 lcore_id, RTE_MAX_LCORE-1);
 185                 return -1;
 186         }
 187
 188         if (global_fds[lcore_id] < 0) {
 189                 RTE_LOG(ERR, GUEST_CHANNEL, "Channel is not connected\n");
 190                 return -1;
 191         }
 192
 193         while (pkt_len > 0) {
 194                 ret = read(global_fds[lcore_id],
 195                                 pkt, pkt_len);
 196
 197                 if (ret < 0) {
 198                         if (errno == EINTR)
 199                                 continue;
 200                         return -1;
 201                 }
 202
 203                 if (ret == 0) {
 204                         RTE_LOG(ERR, GUEST_CHANNEL, "Expected more data, but connection has been closed.\n");
 205                         return -1;
 206                 }
 207                 pkt = (char *)pkt + ret;
 208                 pkt_len -= ret;
 209         }
 210
 211         return 0;
 212 }
 213
 214 int rte_power_guest_channel_receive_msg(void *pkt,
 215                 size_t pkt_len,
 216                 unsigned int lcore_id)
 217 {
 218         return power_guest_channel_read_msg(pkt, pkt_len, lcore_id);
 219 }
 220
 221 void
 222 guest_channel_host_disconnect(unsigned int lcore_id)
 223 {
 224         if (lcore_id >= RTE_MAX_LCORE) {
 225                 RTE_LOG(ERR, GUEST_CHANNEL, "Channel(%u) is out of range 0...%d\n",
 226                                 lcore_id, RTE_MAX_LCORE-1);
 227                 return;
 228         }
 229         if (global_fds[lcore_id] < 0)
 230                 return;
 231         close(global_fds[lcore_id]);
 232         global_fds[lcore_id] = -1;
 233 }