xenbus_comms.c revision 1.2.10.3
1 1.2.10.3 kardel /* $NetBSD: xenbus_comms.c,v 1.2.10.3 2006/06/01 22:35:39 kardel Exp $ */ 2 1.2.10.2 simonb /****************************************************************************** 3 1.2.10.2 simonb * xenbus_comms.c 4 1.2.10.2 simonb * 5 1.2.10.2 simonb * Low level code to talks to Xen Store: ringbuffer and event channel. 6 1.2.10.2 simonb * 7 1.2.10.2 simonb * Copyright (C) 2005 Rusty Russell, IBM Corporation 8 1.2.10.2 simonb * 9 1.2.10.2 simonb * This file may be distributed separately from the Linux kernel, or 10 1.2.10.2 simonb * incorporated into other software packages, subject to the following license: 11 1.2.10.2 simonb * 12 1.2.10.2 simonb * Permission is hereby granted, free of charge, to any person obtaining a copy 13 1.2.10.2 simonb * of this source file (the "Software"), to deal in the Software without 14 1.2.10.2 simonb * restriction, including without limitation the rights to use, copy, modify, 15 1.2.10.2 simonb * merge, publish, distribute, sublicense, and/or sell copies of the Software, 16 1.2.10.2 simonb * and to permit persons to whom the Software is furnished to do so, subject to 17 1.2.10.2 simonb * the following conditions: 18 1.2.10.2 simonb * 19 1.2.10.2 simonb * The above copyright notice and this permission notice shall be included in 20 1.2.10.2 simonb * all copies or substantial portions of the Software. 21 1.2.10.2 simonb * 22 1.2.10.2 simonb * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 23 1.2.10.2 simonb * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 24 1.2.10.2 simonb * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 25 1.2.10.2 simonb * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 26 1.2.10.2 simonb * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 27 1.2.10.2 simonb * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS 28 1.2.10.2 simonb * IN THE SOFTWARE. 29 1.2.10.2 simonb */ 30 1.2.10.2 simonb 31 1.2.10.2 simonb #include <sys/cdefs.h> 32 1.2.10.3 kardel __KERNEL_RCSID(0, "$NetBSD: xenbus_comms.c,v 1.2.10.3 2006/06/01 22:35:39 kardel Exp $"); 33 1.2.10.2 simonb 34 1.2.10.2 simonb #include <sys/types.h> 35 1.2.10.2 simonb #include <sys/null.h> 36 1.2.10.2 simonb #include <sys/errno.h> 37 1.2.10.2 simonb #include <sys/malloc.h> 38 1.2.10.2 simonb #include <sys/param.h> 39 1.2.10.2 simonb #include <sys/proc.h> 40 1.2.10.2 simonb #include <sys/systm.h> 41 1.2.10.2 simonb 42 1.2.10.2 simonb #include <machine/hypervisor.h> 43 1.2.10.2 simonb #include <machine/evtchn.h> 44 1.2.10.2 simonb #include <machine/xenbus.h> 45 1.2.10.2 simonb #include "xenbus_comms.h" 46 1.2.10.2 simonb 47 1.2.10.2 simonb #undef XENDEBUG 48 1.2.10.2 simonb #ifdef XENDEBUG 49 1.2.10.2 simonb #define XENPRINTF(x) printf x 50 1.2.10.2 simonb #else 51 1.2.10.2 simonb #define XENPRINTF(x) 52 1.2.10.2 simonb #endif 53 1.2.10.2 simonb 54 1.2.10.2 simonb struct xenstore_domain_interface *xenstore_interface; 55 1.2.10.2 simonb 56 1.2.10.2 simonb static int xenbus_irq = 0; 57 1.2.10.2 simonb 58 1.2.10.2 simonb extern int xenstored_ready; 59 1.2.10.2 simonb // static DECLARE_WORK(probe_work, xenbus_probe, NULL); 60 1.2.10.2 simonb 61 1.2.10.2 simonb static int wake_waiting(void *); 62 1.2.10.2 simonb static int check_indexes(XENSTORE_RING_IDX, XENSTORE_RING_IDX); 63 1.2.10.2 simonb static void * get_output_chunk(XENSTORE_RING_IDX, XENSTORE_RING_IDX, 64 1.2.10.2 simonb char *, uint32_t *); 65 1.2.10.2 simonb static const void * get_input_chunk(XENSTORE_RING_IDX, XENSTORE_RING_IDX, 66 1.2.10.2 simonb const char *, uint32_t *); 67 1.2.10.2 simonb 68 1.2.10.2 simonb 69 1.2.10.2 simonb static inline struct xenstore_domain_interface * 70 1.2.10.2 simonb xenstore_domain_interface(void) 71 1.2.10.2 simonb { 72 1.2.10.2 simonb return xenstore_interface; 73 1.2.10.2 simonb } 74 1.2.10.2 simonb 75 1.2.10.2 simonb static int 76 1.2.10.2 simonb wake_waiting(void *arg) 77 1.2.10.2 simonb { 78 1.2.10.3 kardel if (__predict_false(xenstored_ready == 0 && 79 1.2.10.3 kardel xen_start_info.flags & SIF_INITDOMAIN)) { 80 1.2.10.2 simonb xenstored_ready = 1; 81 1.2.10.3 kardel wakeup(&xenstored_ready); 82 1.2.10.2 simonb } 83 1.2.10.2 simonb 84 1.2.10.2 simonb wakeup(&xenstore_interface); 85 1.2.10.2 simonb return 1; 86 1.2.10.2 simonb } 87 1.2.10.2 simonb 88 1.2.10.2 simonb static int 89 1.2.10.2 simonb check_indexes(XENSTORE_RING_IDX cons, XENSTORE_RING_IDX prod) 90 1.2.10.2 simonb { 91 1.2.10.2 simonb return ((prod - cons) <= XENSTORE_RING_SIZE); 92 1.2.10.2 simonb } 93 1.2.10.2 simonb 94 1.2.10.2 simonb static void * 95 1.2.10.2 simonb get_output_chunk(XENSTORE_RING_IDX cons, 96 1.2.10.2 simonb XENSTORE_RING_IDX prod, 97 1.2.10.2 simonb char *buf, uint32_t *len) 98 1.2.10.2 simonb { 99 1.2.10.2 simonb *len = XENSTORE_RING_SIZE - MASK_XENSTORE_IDX(prod); 100 1.2.10.2 simonb if ((XENSTORE_RING_SIZE - (prod - cons)) < *len) 101 1.2.10.2 simonb *len = XENSTORE_RING_SIZE - (prod - cons); 102 1.2.10.2 simonb return buf + MASK_XENSTORE_IDX(prod); 103 1.2.10.2 simonb } 104 1.2.10.2 simonb 105 1.2.10.2 simonb static const void * 106 1.2.10.2 simonb get_input_chunk(XENSTORE_RING_IDX cons, 107 1.2.10.2 simonb XENSTORE_RING_IDX prod, 108 1.2.10.2 simonb const char *buf, uint32_t *len) 109 1.2.10.2 simonb { 110 1.2.10.2 simonb *len = XENSTORE_RING_SIZE - MASK_XENSTORE_IDX(cons); 111 1.2.10.2 simonb if ((prod - cons) < *len) 112 1.2.10.2 simonb *len = prod - cons; 113 1.2.10.2 simonb return buf + MASK_XENSTORE_IDX(cons); 114 1.2.10.2 simonb } 115 1.2.10.2 simonb 116 1.2.10.2 simonb int 117 1.2.10.2 simonb xb_write(const void *data, unsigned len) 118 1.2.10.2 simonb { 119 1.2.10.2 simonb struct xenstore_domain_interface *intf = xenstore_domain_interface(); 120 1.2.10.2 simonb XENSTORE_RING_IDX cons, prod; 121 1.2.10.2 simonb 122 1.2.10.2 simonb int s = spltty(); 123 1.2.10.2 simonb 124 1.2.10.2 simonb while (len != 0) { 125 1.2.10.2 simonb void *dst; 126 1.2.10.2 simonb unsigned int avail; 127 1.2.10.2 simonb 128 1.2.10.2 simonb while ((intf->req_prod - intf->req_cons) == XENSTORE_RING_SIZE) { 129 1.2.10.2 simonb XENPRINTF(("xb_write tsleep\n")); 130 1.2.10.2 simonb tsleep(&xenstore_interface, PRIBIO, "wrst", 0); 131 1.2.10.2 simonb XENPRINTF(("xb_write tsleep done\n")); 132 1.2.10.2 simonb } 133 1.2.10.2 simonb 134 1.2.10.2 simonb /* Read indexes, then verify. */ 135 1.2.10.2 simonb cons = intf->req_cons; 136 1.2.10.2 simonb prod = intf->req_prod; 137 1.2.10.2 simonb x86_lfence(); 138 1.2.10.2 simonb if (!check_indexes(cons, prod)) { 139 1.2.10.2 simonb splx(s); 140 1.2.10.2 simonb return EIO; 141 1.2.10.2 simonb } 142 1.2.10.2 simonb 143 1.2.10.2 simonb dst = get_output_chunk(cons, prod, intf->req, &avail); 144 1.2.10.2 simonb if (avail == 0) 145 1.2.10.2 simonb continue; 146 1.2.10.2 simonb if (avail > len) 147 1.2.10.2 simonb avail = len; 148 1.2.10.2 simonb 149 1.2.10.2 simonb memcpy(dst, data, avail); 150 1.2.10.2 simonb data = (const char *)data + avail; 151 1.2.10.2 simonb len -= avail; 152 1.2.10.2 simonb 153 1.2.10.2 simonb /* Other side must not see new header until data is there. */ 154 1.2.10.2 simonb x86_lfence(); 155 1.2.10.2 simonb intf->req_prod += avail; 156 1.2.10.2 simonb x86_lfence(); 157 1.2.10.2 simonb 158 1.2.10.2 simonb hypervisor_notify_via_evtchn(xen_start_info.store_evtchn); 159 1.2.10.2 simonb } 160 1.2.10.2 simonb 161 1.2.10.2 simonb splx(s); 162 1.2.10.2 simonb return 0; 163 1.2.10.2 simonb } 164 1.2.10.2 simonb 165 1.2.10.2 simonb int 166 1.2.10.2 simonb xb_read(void *data, unsigned len) 167 1.2.10.2 simonb { 168 1.2.10.2 simonb struct xenstore_domain_interface *intf = xenstore_domain_interface(); 169 1.2.10.2 simonb XENSTORE_RING_IDX cons, prod; 170 1.2.10.2 simonb 171 1.2.10.2 simonb int s = spltty(); 172 1.2.10.2 simonb 173 1.2.10.2 simonb while (len != 0) { 174 1.2.10.2 simonb unsigned int avail; 175 1.2.10.2 simonb const char *src; 176 1.2.10.2 simonb 177 1.2.10.2 simonb while (intf->rsp_cons == intf->rsp_prod) 178 1.2.10.2 simonb tsleep(&xenstore_interface, PRIBIO, "rdst", 0); 179 1.2.10.2 simonb 180 1.2.10.2 simonb /* Read indexes, then verify. */ 181 1.2.10.2 simonb cons = intf->rsp_cons; 182 1.2.10.2 simonb prod = intf->rsp_prod; 183 1.2.10.2 simonb x86_lfence(); 184 1.2.10.2 simonb if (!check_indexes(cons, prod)) { 185 1.2.10.2 simonb XENPRINTF(("xb_read EIO\n")); 186 1.2.10.2 simonb splx(s); 187 1.2.10.2 simonb return EIO; 188 1.2.10.2 simonb } 189 1.2.10.2 simonb 190 1.2.10.2 simonb src = get_input_chunk(cons, prod, intf->rsp, &avail); 191 1.2.10.2 simonb if (avail == 0) 192 1.2.10.2 simonb continue; 193 1.2.10.2 simonb if (avail > len) 194 1.2.10.2 simonb avail = len; 195 1.2.10.2 simonb 196 1.2.10.2 simonb /* We must read header before we read data. */ 197 1.2.10.2 simonb x86_lfence(); 198 1.2.10.2 simonb 199 1.2.10.2 simonb memcpy(data, src, avail); 200 1.2.10.2 simonb data = (char *)data + avail; 201 1.2.10.2 simonb len -= avail; 202 1.2.10.2 simonb 203 1.2.10.2 simonb /* Other side must not see free space until we've copied out */ 204 1.2.10.2 simonb x86_lfence(); 205 1.2.10.2 simonb intf->rsp_cons += avail; 206 1.2.10.2 simonb x86_lfence(); 207 1.2.10.2 simonb 208 1.2.10.2 simonb XENPRINTF(("Finished read of %i bytes (%i to go)\n", 209 1.2.10.2 simonb avail, len)); 210 1.2.10.2 simonb 211 1.2.10.2 simonb hypervisor_notify_via_evtchn(xen_start_info.store_evtchn); 212 1.2.10.2 simonb } 213 1.2.10.2 simonb 214 1.2.10.2 simonb splx(s); 215 1.2.10.2 simonb return 0; 216 1.2.10.2 simonb } 217 1.2.10.2 simonb 218 1.2.10.2 simonb /* Set up interrupt handler off store event channel. */ 219 1.2.10.2 simonb int 220 1.2.10.2 simonb xb_init_comms(struct device *dev) 221 1.2.10.2 simonb { 222 1.2.10.2 simonb int err; 223 1.2.10.2 simonb 224 1.2.10.2 simonb if (xenbus_irq) 225 1.2.10.2 simonb event_remove_handler(xenbus_irq, wake_waiting, NULL); 226 1.2.10.2 simonb 227 1.2.10.2 simonb err = event_set_handler(xen_start_info.store_evtchn, wake_waiting, 228 1.2.10.2 simonb NULL, IPL_TTY, "xenbus"); 229 1.2.10.2 simonb if (err) { 230 1.2.10.2 simonb printf("XENBUS request irq failed %i\n", err); 231 1.2.10.2 simonb return err; 232 1.2.10.2 simonb } 233 1.2.10.2 simonb xenbus_irq = xen_start_info.store_evtchn; 234 1.2.10.2 simonb printf("%s: using event channel %d\n", dev->dv_xname, xenbus_irq); 235 1.2.10.2 simonb hypervisor_enable_event(xenbus_irq); 236 1.2.10.2 simonb return 0; 237 1.2.10.2 simonb } 238 1.2.10.2 simonb 239 1.2.10.2 simonb /* 240 1.2.10.2 simonb * Local variables: 241 1.2.10.2 simonb * c-file-style: "linux" 242 1.2.10.2 simonb * indent-tabs-mode: t 243 1.2.10.2 simonb * c-indent-level: 8 244 1.2.10.2 simonb * c-basic-offset: 8 245 1.2.10.2 simonb * tab-width: 8 246 1.2.10.2 simonb * End: 247 1.2.10.2 simonb */ 248
Indexes created Sun Oct 19 02:09:48 GMT 2025