1 /* 2 * Copyright (C) International Business Machines Corp., 2005 3 * Author(s): Anthony Liguori <aliguori@us.ibm.com> 4 * 5 * Copyright (C) Red Hat 2007 6 * 7 * Xen Console 8 * 9 * This program is free software; you can redistribute it and/or modify 10 * it under the terms of the GNU General Public License as published by 11 * the Free Software Foundation; under version 2 of the License. 12 * 13 * This program is distributed in the hope that it will be useful, 14 * but WITHOUT ANY WARRANTY; without even the implied warranty of 15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16 * GNU General Public License for more details. 17 * 18 * You should have received a copy of the GNU General Public License along 19 * with this program; if not, see <http://www.gnu.org/licenses/>. 20 */ 21 22 #include "qemu/osdep.h" 23 #include <sys/select.h> 24 #include <termios.h> 25 26 #include "qapi/error.h" 27 #include "hw/hw.h" 28 #include "chardev/char-fe.h" 29 #include "hw/xen/xen_backend.h" 30 31 #include <xen/io/console.h> 32 33 struct buffer { 34 uint8_t *data; 35 size_t consumed; 36 size_t size; 37 size_t capacity; 38 size_t max_capacity; 39 }; 40 41 struct XenConsole { 42 struct XenDevice xendev; /* must be first */ 43 struct buffer buffer; 44 char console[XEN_BUFSIZE]; 45 int ring_ref; 46 void *sring; 47 CharBackend chr; 48 int backlog; 49 }; 50 51 static void buffer_append(struct XenConsole *con) 52 { 53 struct buffer *buffer = &con->buffer; 54 XENCONS_RING_IDX cons, prod, size; 55 struct xencons_interface *intf = con->sring; 56 57 cons = intf->out_cons; 58 prod = intf->out_prod; 59 xen_mb(); 60 61 size = prod - cons; 62 if ((size == 0) || (size > sizeof(intf->out))) 63 return; 64 65 if ((buffer->capacity - buffer->size) < size) { 66 buffer->capacity += (size + 1024); 67 buffer->data = g_realloc(buffer->data, buffer->capacity); 68 } 69 70 while (cons != prod) 71 buffer->data[buffer->size++] = intf->out[ 72 MASK_XENCONS_IDX(cons++, intf->out)]; 73 74 xen_mb(); 75 intf->out_cons = cons; 76 xen_pv_send_notify(&con->xendev); 77 78 if (buffer->max_capacity && 79 buffer->size > buffer->max_capacity) { 80 /* Discard the middle of the data. */ 81 82 size_t over = buffer->size - buffer->max_capacity; 83 uint8_t *maxpos = buffer->data + buffer->max_capacity; 84 85 memmove(maxpos - over, maxpos, over); 86 buffer->data = g_realloc(buffer->data, buffer->max_capacity); 87 buffer->size = buffer->capacity = buffer->max_capacity; 88 89 if (buffer->consumed > buffer->max_capacity - over) 90 buffer->consumed = buffer->max_capacity - over; 91 } 92 } 93 94 static void buffer_advance(struct buffer *buffer, size_t len) 95 { 96 buffer->consumed += len; 97 if (buffer->consumed == buffer->size) { 98 buffer->consumed = 0; 99 buffer->size = 0; 100 } 101 } 102 103 static int ring_free_bytes(struct XenConsole *con) 104 { 105 struct xencons_interface *intf = con->sring; 106 XENCONS_RING_IDX cons, prod, space; 107 108 cons = intf->in_cons; 109 prod = intf->in_prod; 110 xen_mb(); 111 112 space = prod - cons; 113 if (space > sizeof(intf->in)) 114 return 0; /* ring is screwed: ignore it */ 115 116 return (sizeof(intf->in) - space); 117 } 118 119 static int xencons_can_receive(void *opaque) 120 { 121 struct XenConsole *con = opaque; 122 return ring_free_bytes(con); 123 } 124 125 static void xencons_receive(void *opaque, const uint8_t *buf, int len) 126 { 127 struct XenConsole *con = opaque; 128 struct xencons_interface *intf = con->sring; 129 XENCONS_RING_IDX prod; 130 int i, max; 131 132 max = ring_free_bytes(con); 133 /* The can_receive() func limits this, but check again anyway */ 134 if (max < len) 135 len = max; 136 137 prod = intf->in_prod; 138 for (i = 0; i < len; i++) { 139 intf->in[MASK_XENCONS_IDX(prod++, intf->in)] = 140 buf[i]; 141 } 142 xen_wmb(); 143 intf->in_prod = prod; 144 xen_pv_send_notify(&con->xendev); 145 } 146 147 static void xencons_send(struct XenConsole *con) 148 { 149 ssize_t len, size; 150 151 size = con->buffer.size - con->buffer.consumed; 152 if (qemu_chr_fe_backend_connected(&con->chr)) { 153 len = qemu_chr_fe_write(&con->chr, 154 con->buffer.data + con->buffer.consumed, 155 size); 156 } else { 157 len = size; 158 } 159 if (len < 1) { 160 if (!con->backlog) { 161 con->backlog = 1; 162 xen_pv_printf(&con->xendev, 1, 163 "backlog piling up, nobody listening?\n"); 164 } 165 } else { 166 buffer_advance(&con->buffer, len); 167 if (con->backlog && len == size) { 168 con->backlog = 0; 169 xen_pv_printf(&con->xendev, 1, "backlog is gone\n"); 170 } 171 } 172 } 173 174 /* -------------------------------------------------------------------- */ 175 176 static int con_init(struct XenDevice *xendev) 177 { 178 struct XenConsole *con = container_of(xendev, struct XenConsole, xendev); 179 char *type, *dom, label[32]; 180 int ret = 0; 181 const char *output; 182 183 /* setup */ 184 dom = xs_get_domain_path(xenstore, con->xendev.dom); 185 if (!xendev->dev) { 186 snprintf(con->console, sizeof(con->console), "%s/console", dom); 187 } else { 188 snprintf(con->console, sizeof(con->console), "%s/device/console/%d", dom, xendev->dev); 189 } 190 free(dom); 191 192 type = xenstore_read_str(con->console, "type"); 193 if (!type || strcmp(type, "ioemu") != 0) { 194 xen_pv_printf(xendev, 1, "not for me (type=%s)\n", type); 195 ret = -1; 196 goto out; 197 } 198 199 output = xenstore_read_str(con->console, "output"); 200 201 /* no Xen override, use qemu output device */ 202 if (output == NULL) { 203 if (con->xendev.dev) { 204 qemu_chr_fe_init(&con->chr, serial_hd(con->xendev.dev), 205 &error_abort); 206 } 207 } else { 208 snprintf(label, sizeof(label), "xencons%d", con->xendev.dev); 209 qemu_chr_fe_init(&con->chr, 210 qemu_chr_new(label, output), &error_abort); 211 } 212 213 xenstore_store_pv_console_info(con->xendev.dev, 214 qemu_chr_fe_get_driver(&con->chr)); 215 216 out: 217 g_free(type); 218 return ret; 219 } 220 221 static int con_initialise(struct XenDevice *xendev) 222 { 223 struct XenConsole *con = container_of(xendev, struct XenConsole, xendev); 224 int limit; 225 226 if (xenstore_read_int(con->console, "ring-ref", &con->ring_ref) == -1) 227 return -1; 228 if (xenstore_read_int(con->console, "port", &con->xendev.remote_port) == -1) 229 return -1; 230 if (xenstore_read_int(con->console, "limit", &limit) == 0) 231 con->buffer.max_capacity = limit; 232 233 if (!xendev->dev) { 234 xen_pfn_t mfn = con->ring_ref; 235 con->sring = xenforeignmemory_map(xen_fmem, con->xendev.dom, 236 PROT_READ|PROT_WRITE, 237 1, &mfn, NULL); 238 } else { 239 con->sring = xengnttab_map_grant_ref(xendev->gnttabdev, con->xendev.dom, 240 con->ring_ref, 241 PROT_READ|PROT_WRITE); 242 } 243 if (!con->sring) 244 return -1; 245 246 xen_be_bind_evtchn(&con->xendev); 247 qemu_chr_fe_set_handlers(&con->chr, xencons_can_receive, 248 xencons_receive, NULL, NULL, con, NULL, true); 249 250 xen_pv_printf(xendev, 1, 251 "ring mfn %d, remote port %d, local port %d, limit %zd\n", 252 con->ring_ref, 253 con->xendev.remote_port, 254 con->xendev.local_port, 255 con->buffer.max_capacity); 256 return 0; 257 } 258 259 static void con_disconnect(struct XenDevice *xendev) 260 { 261 struct XenConsole *con = container_of(xendev, struct XenConsole, xendev); 262 263 qemu_chr_fe_deinit(&con->chr, false); 264 xen_pv_unbind_evtchn(&con->xendev); 265 266 if (con->sring) { 267 if (!xendev->dev) { 268 xenforeignmemory_unmap(xen_fmem, con->sring, 1); 269 } else { 270 xengnttab_unmap(xendev->gnttabdev, con->sring, 1); 271 } 272 con->sring = NULL; 273 } 274 } 275 276 static void con_event(struct XenDevice *xendev) 277 { 278 struct XenConsole *con = container_of(xendev, struct XenConsole, xendev); 279 280 buffer_append(con); 281 if (con->buffer.size - con->buffer.consumed) 282 xencons_send(con); 283 } 284 285 /* -------------------------------------------------------------------- */ 286 287 struct XenDevOps xen_console_ops = { 288 .size = sizeof(struct XenConsole), 289 .flags = DEVOPS_FLAG_IGNORE_STATE|DEVOPS_FLAG_NEED_GNTDEV, 290 .init = con_init, 291 .initialise = con_initialise, 292 .event = con_event, 293 .disconnect = con_disconnect, 294 }; 295