1 /* 2 * Xen 9p backend 3 * 4 * Copyright Aporeto 2017 5 * 6 * Authors: 7 * Stefano Stabellini <stefano@aporeto.com> 8 * 9 */ 10 11 #include "qemu/osdep.h" 12 13 #include "hw/hw.h" 14 #include "hw/9pfs/9p.h" 15 #include "hw/xen/xen_backend.h" 16 #include "hw/9pfs/xen-9pfs.h" 17 #include "qemu/config-file.h" 18 #include "fsdev/qemu-fsdev.h" 19 20 #define VERSIONS "1" 21 #define MAX_RINGS 8 22 #define MAX_RING_ORDER 8 23 24 typedef struct Xen9pfsRing { 25 struct Xen9pfsDev *priv; 26 27 int ref; 28 xenevtchn_handle *evtchndev; 29 int evtchn; 30 int local_port; 31 int ring_order; 32 struct xen_9pfs_data_intf *intf; 33 unsigned char *data; 34 struct xen_9pfs_data ring; 35 36 struct iovec *sg; 37 QEMUBH *bh; 38 39 /* local copies, so that we can read/write PDU data directly from 40 * the ring */ 41 RING_IDX out_cons, out_size, in_cons; 42 bool inprogress; 43 } Xen9pfsRing; 44 45 typedef struct Xen9pfsDev { 46 struct XenDevice xendev; /* must be first */ 47 V9fsState state; 48 char *path; 49 char *security_model; 50 char *tag; 51 char *id; 52 53 int num_rings; 54 Xen9pfsRing *rings; 55 } Xen9pfsDev; 56 57 static void xen_9pfs_disconnect(struct XenDevice *xendev); 58 59 static void xen_9pfs_in_sg(Xen9pfsRing *ring, 60 struct iovec *in_sg, 61 int *num, 62 uint32_t idx, 63 uint32_t size) 64 { 65 RING_IDX cons, prod, masked_prod, masked_cons; 66 67 cons = ring->intf->in_cons; 68 prod = ring->intf->in_prod; 69 xen_rmb(); 70 masked_prod = xen_9pfs_mask(prod, XEN_FLEX_RING_SIZE(ring->ring_order)); 71 masked_cons = xen_9pfs_mask(cons, XEN_FLEX_RING_SIZE(ring->ring_order)); 72 73 if (masked_prod < masked_cons) { 74 in_sg[0].iov_base = ring->ring.in + masked_prod; 75 in_sg[0].iov_len = masked_cons - masked_prod; 76 *num = 1; 77 } else { 78 in_sg[0].iov_base = ring->ring.in + masked_prod; 79 in_sg[0].iov_len = XEN_FLEX_RING_SIZE(ring->ring_order) - masked_prod; 80 in_sg[1].iov_base = ring->ring.in; 81 in_sg[1].iov_len = masked_cons; 82 *num = 2; 83 } 84 } 85 86 static void xen_9pfs_out_sg(Xen9pfsRing *ring, 87 struct iovec *out_sg, 88 int *num, 89 uint32_t idx) 90 { 91 RING_IDX cons, prod, masked_prod, masked_cons; 92 93 cons = ring->intf->out_cons; 94 prod = ring->intf->out_prod; 95 xen_rmb(); 96 masked_prod = xen_9pfs_mask(prod, XEN_FLEX_RING_SIZE(ring->ring_order)); 97 masked_cons = xen_9pfs_mask(cons, XEN_FLEX_RING_SIZE(ring->ring_order)); 98 99 if (masked_cons < masked_prod) { 100 out_sg[0].iov_base = ring->ring.out + masked_cons; 101 out_sg[0].iov_len = ring->out_size; 102 *num = 1; 103 } else { 104 if (ring->out_size > 105 (XEN_FLEX_RING_SIZE(ring->ring_order) - masked_cons)) { 106 out_sg[0].iov_base = ring->ring.out + masked_cons; 107 out_sg[0].iov_len = XEN_FLEX_RING_SIZE(ring->ring_order) - 108 masked_cons; 109 out_sg[1].iov_base = ring->ring.out; 110 out_sg[1].iov_len = ring->out_size - 111 (XEN_FLEX_RING_SIZE(ring->ring_order) - 112 masked_cons); 113 *num = 2; 114 } else { 115 out_sg[0].iov_base = ring->ring.out + masked_cons; 116 out_sg[0].iov_len = ring->out_size; 117 *num = 1; 118 } 119 } 120 } 121 122 static ssize_t xen_9pfs_pdu_vmarshal(V9fsPDU *pdu, 123 size_t offset, 124 const char *fmt, 125 va_list ap) 126 { 127 Xen9pfsDev *xen_9pfs = container_of(pdu->s, Xen9pfsDev, state); 128 struct iovec in_sg[2]; 129 int num; 130 ssize_t ret; 131 132 xen_9pfs_in_sg(&xen_9pfs->rings[pdu->tag % xen_9pfs->num_rings], 133 in_sg, &num, pdu->idx, ROUND_UP(offset + 128, 512)); 134 135 ret = v9fs_iov_vmarshal(in_sg, num, offset, 0, fmt, ap); 136 if (ret < 0) { 137 xen_pv_printf(&xen_9pfs->xendev, 0, 138 "Failed to encode VirtFS request type %d\n", pdu->id + 1); 139 xen_be_set_state(&xen_9pfs->xendev, XenbusStateClosing); 140 xen_9pfs_disconnect(&xen_9pfs->xendev); 141 } 142 return ret; 143 } 144 145 static ssize_t xen_9pfs_pdu_vunmarshal(V9fsPDU *pdu, 146 size_t offset, 147 const char *fmt, 148 va_list ap) 149 { 150 Xen9pfsDev *xen_9pfs = container_of(pdu->s, Xen9pfsDev, state); 151 struct iovec out_sg[2]; 152 int num; 153 ssize_t ret; 154 155 xen_9pfs_out_sg(&xen_9pfs->rings[pdu->tag % xen_9pfs->num_rings], 156 out_sg, &num, pdu->idx); 157 158 ret = v9fs_iov_vunmarshal(out_sg, num, offset, 0, fmt, ap); 159 if (ret < 0) { 160 xen_pv_printf(&xen_9pfs->xendev, 0, 161 "Failed to decode VirtFS request type %d\n", pdu->id); 162 xen_be_set_state(&xen_9pfs->xendev, XenbusStateClosing); 163 xen_9pfs_disconnect(&xen_9pfs->xendev); 164 } 165 return ret; 166 } 167 168 static void xen_9pfs_init_out_iov_from_pdu(V9fsPDU *pdu, 169 struct iovec **piov, 170 unsigned int *pniov, 171 size_t size) 172 { 173 Xen9pfsDev *xen_9pfs = container_of(pdu->s, Xen9pfsDev, state); 174 Xen9pfsRing *ring = &xen_9pfs->rings[pdu->tag % xen_9pfs->num_rings]; 175 int num; 176 177 g_free(ring->sg); 178 179 ring->sg = g_malloc0(sizeof(*ring->sg) * 2); 180 xen_9pfs_out_sg(ring, ring->sg, &num, pdu->idx); 181 *piov = ring->sg; 182 *pniov = num; 183 } 184 185 static void xen_9pfs_init_in_iov_from_pdu(V9fsPDU *pdu, 186 struct iovec **piov, 187 unsigned int *pniov, 188 size_t size) 189 { 190 Xen9pfsDev *xen_9pfs = container_of(pdu->s, Xen9pfsDev, state); 191 Xen9pfsRing *ring = &xen_9pfs->rings[pdu->tag % xen_9pfs->num_rings]; 192 int num; 193 size_t buf_size; 194 195 g_free(ring->sg); 196 197 ring->sg = g_malloc0(sizeof(*ring->sg) * 2); 198 xen_9pfs_in_sg(ring, ring->sg, &num, pdu->idx, size); 199 200 buf_size = iov_size(ring->sg, num); 201 if (buf_size < size) { 202 xen_pv_printf(&xen_9pfs->xendev, 0, "Xen 9pfs request type %d" 203 "needs %zu bytes, buffer has %zu\n", pdu->id, size, 204 buf_size); 205 xen_be_set_state(&xen_9pfs->xendev, XenbusStateClosing); 206 xen_9pfs_disconnect(&xen_9pfs->xendev); 207 } 208 209 *piov = ring->sg; 210 *pniov = num; 211 } 212 213 static void xen_9pfs_push_and_notify(V9fsPDU *pdu) 214 { 215 RING_IDX prod; 216 Xen9pfsDev *priv = container_of(pdu->s, Xen9pfsDev, state); 217 Xen9pfsRing *ring = &priv->rings[pdu->tag % priv->num_rings]; 218 219 g_free(ring->sg); 220 ring->sg = NULL; 221 222 ring->intf->out_cons = ring->out_cons; 223 xen_wmb(); 224 225 prod = ring->intf->in_prod; 226 xen_rmb(); 227 ring->intf->in_prod = prod + pdu->size; 228 xen_wmb(); 229 230 ring->inprogress = false; 231 xenevtchn_notify(ring->evtchndev, ring->local_port); 232 233 qemu_bh_schedule(ring->bh); 234 } 235 236 static const V9fsTransport xen_9p_transport = { 237 .pdu_vmarshal = xen_9pfs_pdu_vmarshal, 238 .pdu_vunmarshal = xen_9pfs_pdu_vunmarshal, 239 .init_in_iov_from_pdu = xen_9pfs_init_in_iov_from_pdu, 240 .init_out_iov_from_pdu = xen_9pfs_init_out_iov_from_pdu, 241 .push_and_notify = xen_9pfs_push_and_notify, 242 }; 243 244 static int xen_9pfs_init(struct XenDevice *xendev) 245 { 246 return 0; 247 } 248 249 static int xen_9pfs_receive(Xen9pfsRing *ring) 250 { 251 P9MsgHeader h; 252 RING_IDX cons, prod, masked_prod, masked_cons, queued; 253 V9fsPDU *pdu; 254 255 if (ring->inprogress) { 256 return 0; 257 } 258 259 cons = ring->intf->out_cons; 260 prod = ring->intf->out_prod; 261 xen_rmb(); 262 263 queued = xen_9pfs_queued(prod, cons, XEN_FLEX_RING_SIZE(ring->ring_order)); 264 if (queued < sizeof(h)) { 265 return 0; 266 } 267 ring->inprogress = true; 268 269 masked_prod = xen_9pfs_mask(prod, XEN_FLEX_RING_SIZE(ring->ring_order)); 270 masked_cons = xen_9pfs_mask(cons, XEN_FLEX_RING_SIZE(ring->ring_order)); 271 272 xen_9pfs_read_packet((uint8_t *) &h, ring->ring.out, sizeof(h), 273 masked_prod, &masked_cons, 274 XEN_FLEX_RING_SIZE(ring->ring_order)); 275 if (queued < le32_to_cpu(h.size_le)) { 276 return 0; 277 } 278 279 /* cannot fail, because we only handle one request per ring at a time */ 280 pdu = pdu_alloc(&ring->priv->state); 281 ring->out_size = le32_to_cpu(h.size_le); 282 ring->out_cons = cons + le32_to_cpu(h.size_le); 283 284 pdu_submit(pdu, &h); 285 286 return 0; 287 } 288 289 static void xen_9pfs_bh(void *opaque) 290 { 291 Xen9pfsRing *ring = opaque; 292 xen_9pfs_receive(ring); 293 } 294 295 static void xen_9pfs_evtchn_event(void *opaque) 296 { 297 Xen9pfsRing *ring = opaque; 298 evtchn_port_t port; 299 300 port = xenevtchn_pending(ring->evtchndev); 301 xenevtchn_unmask(ring->evtchndev, port); 302 303 qemu_bh_schedule(ring->bh); 304 } 305 306 static void xen_9pfs_disconnect(struct XenDevice *xendev) 307 { 308 Xen9pfsDev *xen_9pdev = container_of(xendev, Xen9pfsDev, xendev); 309 int i; 310 311 for (i = 0; i < xen_9pdev->num_rings; i++) { 312 if (xen_9pdev->rings[i].evtchndev != NULL) { 313 qemu_set_fd_handler(xenevtchn_fd(xen_9pdev->rings[i].evtchndev), 314 NULL, NULL, NULL); 315 xenevtchn_unbind(xen_9pdev->rings[i].evtchndev, 316 xen_9pdev->rings[i].local_port); 317 xen_9pdev->rings[i].evtchndev = NULL; 318 } 319 } 320 } 321 322 static int xen_9pfs_free(struct XenDevice *xendev) 323 { 324 Xen9pfsDev *xen_9pdev = container_of(xendev, Xen9pfsDev, xendev); 325 int i; 326 327 if (xen_9pdev->rings[0].evtchndev != NULL) { 328 xen_9pfs_disconnect(xendev); 329 } 330 331 for (i = 0; i < xen_9pdev->num_rings; i++) { 332 if (xen_9pdev->rings[i].data != NULL) { 333 xengnttab_unmap(xen_9pdev->xendev.gnttabdev, 334 xen_9pdev->rings[i].data, 335 (1 << xen_9pdev->rings[i].ring_order)); 336 } 337 if (xen_9pdev->rings[i].intf != NULL) { 338 xengnttab_unmap(xen_9pdev->xendev.gnttabdev, 339 xen_9pdev->rings[i].intf, 340 1); 341 } 342 if (xen_9pdev->rings[i].bh != NULL) { 343 qemu_bh_delete(xen_9pdev->rings[i].bh); 344 } 345 } 346 347 g_free(xen_9pdev->id); 348 g_free(xen_9pdev->tag); 349 g_free(xen_9pdev->path); 350 g_free(xen_9pdev->security_model); 351 g_free(xen_9pdev->rings); 352 return 0; 353 } 354 355 static int xen_9pfs_connect(struct XenDevice *xendev) 356 { 357 int i; 358 Xen9pfsDev *xen_9pdev = container_of(xendev, Xen9pfsDev, xendev); 359 V9fsState *s = &xen_9pdev->state; 360 QemuOpts *fsdev; 361 362 if (xenstore_read_fe_int(&xen_9pdev->xendev, "num-rings", 363 &xen_9pdev->num_rings) == -1 || 364 xen_9pdev->num_rings > MAX_RINGS || xen_9pdev->num_rings < 1) { 365 return -1; 366 } 367 368 xen_9pdev->rings = g_malloc0(xen_9pdev->num_rings * sizeof(Xen9pfsRing)); 369 for (i = 0; i < xen_9pdev->num_rings; i++) { 370 char *str; 371 int ring_order; 372 373 xen_9pdev->rings[i].priv = xen_9pdev; 374 xen_9pdev->rings[i].evtchn = -1; 375 xen_9pdev->rings[i].local_port = -1; 376 377 str = g_strdup_printf("ring-ref%u", i); 378 if (xenstore_read_fe_int(&xen_9pdev->xendev, str, 379 &xen_9pdev->rings[i].ref) == -1) { 380 g_free(str); 381 goto out; 382 } 383 g_free(str); 384 str = g_strdup_printf("event-channel-%u", i); 385 if (xenstore_read_fe_int(&xen_9pdev->xendev, str, 386 &xen_9pdev->rings[i].evtchn) == -1) { 387 g_free(str); 388 goto out; 389 } 390 g_free(str); 391 392 xen_9pdev->rings[i].intf = xengnttab_map_grant_ref( 393 xen_9pdev->xendev.gnttabdev, 394 xen_9pdev->xendev.dom, 395 xen_9pdev->rings[i].ref, 396 PROT_READ | PROT_WRITE); 397 if (!xen_9pdev->rings[i].intf) { 398 goto out; 399 } 400 ring_order = xen_9pdev->rings[i].intf->ring_order; 401 if (ring_order > MAX_RING_ORDER) { 402 goto out; 403 } 404 xen_9pdev->rings[i].ring_order = ring_order; 405 xen_9pdev->rings[i].data = xengnttab_map_domain_grant_refs( 406 xen_9pdev->xendev.gnttabdev, 407 (1 << ring_order), 408 xen_9pdev->xendev.dom, 409 xen_9pdev->rings[i].intf->ref, 410 PROT_READ | PROT_WRITE); 411 if (!xen_9pdev->rings[i].data) { 412 goto out; 413 } 414 xen_9pdev->rings[i].ring.in = xen_9pdev->rings[i].data; 415 xen_9pdev->rings[i].ring.out = xen_9pdev->rings[i].data + 416 XEN_FLEX_RING_SIZE(ring_order); 417 418 xen_9pdev->rings[i].bh = qemu_bh_new(xen_9pfs_bh, &xen_9pdev->rings[i]); 419 xen_9pdev->rings[i].out_cons = 0; 420 xen_9pdev->rings[i].out_size = 0; 421 xen_9pdev->rings[i].inprogress = false; 422 423 424 xen_9pdev->rings[i].evtchndev = xenevtchn_open(NULL, 0); 425 if (xen_9pdev->rings[i].evtchndev == NULL) { 426 goto out; 427 } 428 qemu_set_cloexec(xenevtchn_fd(xen_9pdev->rings[i].evtchndev)); 429 xen_9pdev->rings[i].local_port = xenevtchn_bind_interdomain 430 (xen_9pdev->rings[i].evtchndev, 431 xendev->dom, 432 xen_9pdev->rings[i].evtchn); 433 if (xen_9pdev->rings[i].local_port == -1) { 434 xen_pv_printf(xendev, 0, 435 "xenevtchn_bind_interdomain failed port=%d\n", 436 xen_9pdev->rings[i].evtchn); 437 goto out; 438 } 439 xen_pv_printf(xendev, 2, "bind evtchn port %d\n", xendev->local_port); 440 qemu_set_fd_handler(xenevtchn_fd(xen_9pdev->rings[i].evtchndev), 441 xen_9pfs_evtchn_event, NULL, &xen_9pdev->rings[i]); 442 } 443 444 xen_9pdev->security_model = xenstore_read_be_str(xendev, "security_model"); 445 xen_9pdev->path = xenstore_read_be_str(xendev, "path"); 446 xen_9pdev->id = s->fsconf.fsdev_id = 447 g_strdup_printf("xen9p%d", xendev->dev); 448 xen_9pdev->tag = s->fsconf.tag = xenstore_read_fe_str(xendev, "tag"); 449 v9fs_register_transport(s, &xen_9p_transport); 450 fsdev = qemu_opts_create(qemu_find_opts("fsdev"), 451 s->fsconf.tag, 452 1, NULL); 453 qemu_opt_set(fsdev, "fsdriver", "local", NULL); 454 qemu_opt_set(fsdev, "path", xen_9pdev->path, NULL); 455 qemu_opt_set(fsdev, "security_model", xen_9pdev->security_model, NULL); 456 qemu_opts_set_id(fsdev, s->fsconf.fsdev_id); 457 qemu_fsdev_add(fsdev); 458 v9fs_device_realize_common(s, NULL); 459 460 return 0; 461 462 out: 463 xen_9pfs_free(xendev); 464 return -1; 465 } 466 467 static void xen_9pfs_alloc(struct XenDevice *xendev) 468 { 469 xenstore_write_be_str(xendev, "versions", VERSIONS); 470 xenstore_write_be_int(xendev, "max-rings", MAX_RINGS); 471 xenstore_write_be_int(xendev, "max-ring-page-order", MAX_RING_ORDER); 472 } 473 474 struct XenDevOps xen_9pfs_ops = { 475 .size = sizeof(Xen9pfsDev), 476 .flags = DEVOPS_FLAG_NEED_GNTDEV, 477 .alloc = xen_9pfs_alloc, 478 .init = xen_9pfs_init, 479 .initialise = xen_9pfs_connect, 480 .disconnect = xen_9pfs_disconnect, 481 .free = xen_9pfs_free, 482 }; 483