1 /****************************************************************************** 2 * Copyright (C) 2005 XenSource Ltd 3 * 4 * This file may be distributed separately from the Linux kernel, or 5 * incorporated into other software packages, subject to the following license: 6 * 7 * Permission is hereby granted, free of charge, to any person obtaining a copy 8 * of this source file (the "Software"), to deal in the Software without 9 * restriction, including without limitation the rights to use, copy, modify, 10 * merge, publish, distribute, sublicense, and/or sell copies of the Software, 11 * and to permit persons to whom the Software is furnished to do so, subject to 12 * the following conditions: 13 * 14 * The above copyright notice and this permission notice shall be included in 15 * all copies or substantial portions of the Software. 16 * 17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 18 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 19 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 20 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 21 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 22 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS 23 * IN THE SOFTWARE. 24 */ 25 26 /** 27 * \file xenbus.c 28 * 29 * \brief Client-facing interface for the Xenbus driver. 30 * 31 * In other words, the interface between the Xenbus and the device-specific 32 * code, be it the frontend or the backend of that driver. 33 */ 34 35 #if 0 36 #define DPRINTK(fmt, args...) \ 37 printk("xenbus_client (%s:%d) " fmt ".\n", __FUNCTION__, __LINE__, ##args) 38 #else 39 #define DPRINTK(fmt, args...) ((void)0) 40 #endif 41 42 #include <sys/cdefs.h> 43 __FBSDID("$FreeBSD$"); 44 45 #include <sys/cdefs.h> 46 #include <sys/param.h> 47 #include <sys/kernel.h> 48 #include <sys/types.h> 49 #include <sys/malloc.h> 50 #include <sys/libkern.h> 51 #include <sys/sbuf.h> 52 53 #include <machine/xen/xen-os.h> 54 #include <xen/hypervisor.h> 55 #include <xen/evtchn.h> 56 #include <xen/gnttab.h> 57 #include <xen/xenbus/xenbusvar.h> 58 #include <machine/stdarg.h> 59 60 MALLOC_DEFINE(M_XENBUS, "xenbus", "XenBus Support"); 61 62 /*------------------------- Private Functions --------------------------------*/ 63 /** 64 * \brief Construct the error path corresponding to the given XenBus 65 * device. 66 * 67 * \param dev The XenBus device for which we are constructing an error path. 68 * 69 * \return On success, the contructed error path. Otherwise NULL. 70 * 71 * It is the caller's responsibility to free any returned error path 72 * node using the M_XENBUS malloc type. 73 */ 74 static char * 75 error_path(device_t dev) 76 { 77 char *path_buffer = malloc(strlen("error/") 78 + strlen(xenbus_get_node(dev)) + 1,M_XENBUS, M_WAITOK); 79 80 strcpy(path_buffer, "error/"); 81 strcpy(path_buffer + strlen("error/"), xenbus_get_node(dev)); 82 83 return (path_buffer); 84 } 85 86 /*--------------------------- Public Functions -------------------------------*/ 87 /*-------- API comments for these methods can be found in xenbusvar.h --------*/ 88 const char * 89 xenbus_strstate(XenbusState state) 90 { 91 static const char *const name[] = { 92 [ XenbusStateUnknown ] = "Unknown", 93 [ XenbusStateInitialising ] = "Initialising", 94 [ XenbusStateInitWait ] = "InitWait", 95 [ XenbusStateInitialised ] = "Initialised", 96 [ XenbusStateConnected ] = "Connected", 97 [ XenbusStateClosing ] = "Closing", 98 [ XenbusStateClosed ] = "Closed", 99 }; 100 101 return ((state < (XenbusStateClosed + 1)) ? name[state] : "INVALID"); 102 } 103 104 int 105 xenbus_watch_path(device_t dev, char *path, struct xs_watch *watch, 106 xs_watch_cb_t *callback) 107 { 108 int error; 109 110 watch->node = path; 111 watch->callback = callback; 112 113 error = xs_register_watch(watch); 114 115 if (error) { 116 watch->node = NULL; 117 watch->callback = NULL; 118 xenbus_dev_fatal(dev, error, "adding watch on %s", path); 119 } 120 121 return (error); 122 } 123 124 int 125 xenbus_watch_path2(device_t dev, const char *path, 126 const char *path2, struct xs_watch *watch, 127 xs_watch_cb_t *callback) 128 { 129 int error; 130 char *state = malloc(strlen(path) + 1 + strlen(path2) + 1, 131 M_XENBUS, M_WAITOK); 132 133 strcpy(state, path); 134 strcat(state, "/"); 135 strcat(state, path2); 136 137 error = xenbus_watch_path(dev, state, watch, callback); 138 if (error) { 139 free(state,M_XENBUS); 140 } 141 142 return (error); 143 } 144 145 void 146 xenbus_dev_verror(device_t dev, int err, const char *fmt, va_list ap) 147 { 148 int ret; 149 unsigned int len; 150 char *printf_buffer = NULL, *path_buffer = NULL; 151 152 #define PRINTF_BUFFER_SIZE 4096 153 printf_buffer = malloc(PRINTF_BUFFER_SIZE,M_XENBUS, M_WAITOK); 154 155 len = sprintf(printf_buffer, "%i ", err); 156 ret = vsnprintf(printf_buffer+len, PRINTF_BUFFER_SIZE-len, fmt, ap); 157 158 KASSERT(len + ret <= PRINTF_BUFFER_SIZE-1, ("xenbus error message too big")); 159 device_printf(dev, "Error %s\n", printf_buffer); 160 path_buffer = error_path(dev); 161 162 if (path_buffer == NULL) { 163 printf("xenbus: failed to write error node for %s (%s)\n", 164 xenbus_get_node(dev), printf_buffer); 165 goto fail; 166 } 167 168 if (xs_write(XST_NIL, path_buffer, "error", printf_buffer) != 0) { 169 printf("xenbus: failed to write error node for %s (%s)\n", 170 xenbus_get_node(dev), printf_buffer); 171 goto fail; 172 } 173 174 fail: 175 if (printf_buffer) 176 free(printf_buffer,M_XENBUS); 177 if (path_buffer) 178 free(path_buffer,M_XENBUS); 179 } 180 181 void 182 xenbus_dev_error(device_t dev, int err, const char *fmt, ...) 183 { 184 va_list ap; 185 186 va_start(ap, fmt); 187 xenbus_dev_verror(dev, err, fmt, ap); 188 va_end(ap); 189 } 190 191 void 192 xenbus_dev_vfatal(device_t dev, int err, const char *fmt, va_list ap) 193 { 194 xenbus_dev_verror(dev, err, fmt, ap); 195 device_printf(dev, "Fatal error. Transitioning to Closing State\n"); 196 xenbus_set_state(dev, XenbusStateClosing); 197 } 198 199 void 200 xenbus_dev_fatal(device_t dev, int err, const char *fmt, ...) 201 { 202 va_list ap; 203 204 va_start(ap, fmt); 205 xenbus_dev_vfatal(dev, err, fmt, ap); 206 va_end(ap); 207 } 208 209 int 210 xenbus_grant_ring(device_t dev, unsigned long ring_mfn, grant_ref_t *refp) 211 { 212 int error; 213 214 error = gnttab_grant_foreign_access( 215 xenbus_get_otherend_id(dev), ring_mfn, 0, refp); 216 if (error) { 217 xenbus_dev_fatal(dev, error, "granting access to ring page"); 218 return (error); 219 } 220 221 return (0); 222 } 223 224 int 225 xenbus_alloc_evtchn(device_t dev, evtchn_port_t *port) 226 { 227 struct evtchn_alloc_unbound alloc_unbound; 228 int err; 229 230 alloc_unbound.dom = DOMID_SELF; 231 alloc_unbound.remote_dom = xenbus_get_otherend_id(dev); 232 233 err = HYPERVISOR_event_channel_op(EVTCHNOP_alloc_unbound, 234 &alloc_unbound); 235 236 if (err) { 237 xenbus_dev_fatal(dev, -err, "allocating event channel"); 238 return (-err); 239 } 240 *port = alloc_unbound.port; 241 return (0); 242 } 243 244 int 245 xenbus_free_evtchn(device_t dev, evtchn_port_t port) 246 { 247 struct evtchn_close close; 248 int err; 249 250 close.port = port; 251 252 err = HYPERVISOR_event_channel_op(EVTCHNOP_close, &close); 253 if (err) { 254 xenbus_dev_error(dev, -err, "freeing event channel %d", port); 255 return (-err); 256 } 257 return (0); 258 } 259 260 XenbusState 261 xenbus_read_driver_state(const char *path) 262 { 263 XenbusState result; 264 int error; 265 266 error = xs_gather(XST_NIL, path, "state", "%d", &result, NULL); 267 if (error) 268 result = XenbusStateClosed; 269 270 return (result); 271 } 272 273 int 274 xenbus_dev_is_online(device_t dev) 275 { 276 const char *path; 277 int error; 278 int value; 279 280 path = xenbus_get_node(dev); 281 error = xs_gather(XST_NIL, path, "online", "%d", &value, NULL); 282 if (error != 0) { 283 /* Default to not online. */ 284 value = 0; 285 } 286 287 return (value); 288 } 289