| 1 | /* |
| 2 | * QEMU Xen backend support: Operations for true Xen |
| 3 | * |
| 4 | * Copyright © 2022 Amazon.com, Inc. or its affiliates. All Rights Reserved. |
| 5 | * |
| 6 | * Authors: David Woodhouse <dwmw2@infradead.org> |
| 7 | * |
| 8 | * This work is licensed under the terms of the GNU GPL, version 2 or later. |
| 9 | * See the COPYING file in the top-level directory. |
| 10 | */ |
| 11 | |
| 12 | #include "qemu/osdep.h" |
| 13 | #include "qemu/uuid.h" |
| 14 | #include "qapi/error.h" |
| 15 | |
| 16 | #include "hw/xen/xen_native.h" |
| 17 | #include "hw/xen/xen_backend_ops.h" |
| 18 | |
| 19 | /* |
| 20 | * If we have new enough libxenctrl then we do not want/need these compat |
| 21 | * interfaces, despite what the user supplied cflags might say. They |
| 22 | * must be undefined before including xenctrl.h |
| 23 | */ |
| 24 | #undef XC_WANT_COMPAT_EVTCHN_API |
| 25 | #undef XC_WANT_COMPAT_GNTTAB_API |
| 26 | #undef XC_WANT_COMPAT_MAP_FOREIGN_API |
| 27 | |
| 28 | #include <xenctrl.h> |
| 29 | |
| 30 | /* |
| 31 | * We don't support Xen prior to 4.7.1. |
| 32 | */ |
| 33 | |
| 34 | #include <xenevtchn.h> |
| 35 | #include <xengnttab.h> |
| 36 | #include <xenforeignmemory.h> |
| 37 | |
| 38 | /* Xen before 4.8 */ |
| 39 | |
| 40 | static int libxengnttab_fallback_grant_copy(xengnttab_handle *xgt, |
| 41 | bool to_domain, uint32_t domid, |
| 42 | XenGrantCopySegment segs[], |
| 43 | unsigned int nr_segs, Error **errp) |
| 44 | { |
| 45 | uint32_t *refs = g_new(uint32_t, nr_segs); |
| 46 | int prot = to_domain ? PROT_WRITE : PROT_READ; |
| 47 | void *map; |
| 48 | unsigned int i; |
| 49 | int rc = 0; |
| 50 | |
| 51 | for (i = 0; i < nr_segs; i++) { |
| 52 | XenGrantCopySegment *seg = &segs[i]; |
| 53 | |
| 54 | refs[i] = to_domain ? seg->dest.foreign.ref : |
| 55 | seg->source.foreign.ref; |
| 56 | } |
| 57 | map = xengnttab_map_domain_grant_refs(xgt, nr_segs, domid, refs, prot); |
| 58 | if (!map) { |
| 59 | if (errp) { |
| 60 | error_setg_errno(errp, errno, |
| 61 | "xengnttab_map_domain_grant_refs failed"); |
| 62 | } |
| 63 | rc = -errno; |
| 64 | goto done; |
| 65 | } |
| 66 | |
| 67 | for (i = 0; i < nr_segs; i++) { |
| 68 | XenGrantCopySegment *seg = &segs[i]; |
| 69 | void *page = map + (i * XEN_PAGE_SIZE); |
| 70 | |
| 71 | if (to_domain) { |
| 72 | memcpy(page + seg->dest.foreign.offset, seg->source.virt, |
| 73 | seg->len); |
| 74 | } else { |
| 75 | memcpy(seg->dest.virt, page + seg->source.foreign.offset, |
| 76 | seg->len); |
| 77 | } |
| 78 | } |
| 79 | |
| 80 | if (xengnttab_unmap(xgt, map, nr_segs)) { |
| 81 | if (errp) { |
| 82 | error_setg_errno(errp, errno, "xengnttab_unmap failed"); |
| 83 | } |
| 84 | rc = -errno; |
| 85 | } |
| 86 | |
| 87 | done: |
| 88 | g_free(refs); |
| 89 | return rc; |
| 90 | } |
| 91 | |
| 92 | #if CONFIG_XEN_CTRL_INTERFACE_VERSION >= 40800 |
| 93 | |
| 94 | static int libxengnttab_backend_grant_copy(xengnttab_handle *xgt, |
| 95 | bool to_domain, uint32_t domid, |
| 96 | XenGrantCopySegment *segs, |
| 97 | uint32_t nr_segs, Error **errp) |
| 98 | { |
| 99 | xengnttab_grant_copy_segment_t *xengnttab_segs; |
| 100 | unsigned int i; |
| 101 | int rc; |
| 102 | |
| 103 | xengnttab_segs = g_new0(xengnttab_grant_copy_segment_t, nr_segs); |
| 104 | |
| 105 | for (i = 0; i < nr_segs; i++) { |
| 106 | XenGrantCopySegment *seg = &segs[i]; |
| 107 | xengnttab_grant_copy_segment_t *xengnttab_seg = &xengnttab_segs[i]; |
| 108 | |
| 109 | if (to_domain) { |
| 110 | xengnttab_seg->flags = GNTCOPY_dest_gref; |
| 111 | xengnttab_seg->dest.foreign.domid = domid; |
| 112 | xengnttab_seg->dest.foreign.ref = seg->dest.foreign.ref; |
| 113 | xengnttab_seg->dest.foreign.offset = seg->dest.foreign.offset; |
| 114 | xengnttab_seg->source.virt = seg->source.virt; |
| 115 | } else { |
| 116 | xengnttab_seg->flags = GNTCOPY_source_gref; |
| 117 | xengnttab_seg->source.foreign.domid = domid; |
| 118 | xengnttab_seg->source.foreign.ref = seg->source.foreign.ref; |
| 119 | xengnttab_seg->source.foreign.offset = |
| 120 | seg->source.foreign.offset; |
| 121 | xengnttab_seg->dest.virt = seg->dest.virt; |
| 122 | } |
| 123 | |
| 124 | xengnttab_seg->len = seg->len; |
| 125 | } |
| 126 | |
| 127 | if (xengnttab_grant_copy(xgt, nr_segs, xengnttab_segs)) { |
| 128 | if (errp) { |
| 129 | error_setg_errno(errp, errno, "xengnttab_grant_copy failed"); |
| 130 | } |
| 131 | rc = -errno; |
| 132 | goto done; |
| 133 | } |
| 134 | |
| 135 | rc = 0; |
| 136 | for (i = 0; i < nr_segs; i++) { |
| 137 | xengnttab_grant_copy_segment_t *xengnttab_seg = &xengnttab_segs[i]; |
| 138 | |
| 139 | if (xengnttab_seg->status != GNTST_okay) { |
| 140 | if (errp) { |
| 141 | error_setg(errp, "xengnttab_grant_copy seg[%u] failed", i); |
| 142 | } |
| 143 | rc = -EIO; |
| 144 | break; |
| 145 | } |
| 146 | } |
| 147 | |
| 148 | done: |
| 149 | g_free(xengnttab_segs); |
| 150 | return rc; |
| 151 | } |
| 152 | #endif |
| 153 | |
| 154 | static xenevtchn_handle *libxenevtchn_backend_open(void) |
| 155 | { |
| 156 | return xenevtchn_open(NULL, 0); |
| 157 | } |
| 158 | |
| 159 | struct evtchn_backend_ops libxenevtchn_backend_ops = { |
| 160 | .open = libxenevtchn_backend_open, |
| 161 | .close = xenevtchn_close, |
| 162 | .bind_interdomain = xenevtchn_bind_interdomain, |
| 163 | .unbind = xenevtchn_unbind, |
| 164 | .get_fd = xenevtchn_fd, |
| 165 | .notify = xenevtchn_notify, |
| 166 | .unmask = xenevtchn_unmask, |
| 167 | .pending = xenevtchn_pending, |
| 168 | }; |
| 169 | |
| 170 | static xengnttab_handle *libxengnttab_backend_open(void) |
| 171 | { |
| 172 | return xengnttab_open(NULL, 0); |
| 173 | } |
| 174 | |
| 175 | static int libxengnttab_backend_unmap(xengnttab_handle *xgt, |
| 176 | void *start_address, uint32_t *refs, |
| 177 | uint32_t count) |
| 178 | { |
| 179 | return xengnttab_unmap(xgt, start_address, count); |
| 180 | } |
| 181 | |
| 182 | |
| 183 | static struct gnttab_backend_ops libxengnttab_backend_ops = { |
| 184 | .features = XEN_GNTTAB_OP_FEATURE_MAP_MULTIPLE, |
| 185 | .open = libxengnttab_backend_open, |
| 186 | .close = xengnttab_close, |
| 187 | .grant_copy = libxengnttab_fallback_grant_copy, |
| 188 | .set_max_grants = xengnttab_set_max_grants, |
| 189 | .map_refs = xengnttab_map_domain_grant_refs, |
| 190 | .unmap = libxengnttab_backend_unmap, |
| 191 | }; |
| 192 | |
| 193 | static void *libxenforeignmem_backend_map(uint32_t dom, void *addr, int prot, |
| 194 | size_t pages, xen_pfn_t *pfns, |
| 195 | int *errs) |
| 196 | { |
| 197 | return xenforeignmemory_map2(xen_fmem, dom, addr, prot, 0, pages, pfns, |
| 198 | errs); |
| 199 | } |
| 200 | |
| 201 | static int libxenforeignmem_backend_unmap(void *addr, size_t pages) |
| 202 | { |
| 203 | return xenforeignmemory_unmap(xen_fmem, addr, pages); |
| 204 | } |
| 205 | |
| 206 | struct foreignmem_backend_ops libxenforeignmem_backend_ops = { |
| 207 | .map = libxenforeignmem_backend_map, |
| 208 | .unmap = libxenforeignmem_backend_unmap, |
| 209 | }; |
| 210 | |
| 211 | struct qemu_xs_handle { |
| 212 | struct xs_handle *xsh; |
| 213 | NotifierList notifiers; |
| 214 | }; |
| 215 | |
| 216 | static void watch_event(void *opaque) |
| 217 | { |
| 218 | struct qemu_xs_handle *h = opaque; |
| 219 | |
| 220 | for (;;) { |
| 221 | char **v = xs_check_watch(h->xsh); |
| 222 | |
| 223 | if (!v) { |
| 224 | break; |
| 225 | } |
| 226 | |
| 227 | notifier_list_notify(&h->notifiers, v); |
| 228 | free(v); |
| 229 | } |
| 230 | } |
| 231 | |
| 232 | static struct qemu_xs_handle *libxenstore_open(void) |
| 233 | { |
| 234 | struct xs_handle *xsh = xs_open(0); |
| 235 | struct qemu_xs_handle *h; |
| 236 | |
| 237 | if (!xsh) { |
| 238 | return NULL; |
| 239 | } |
| 240 | |
| 241 | h = g_new0(struct qemu_xs_handle, 1); |
| 242 | h->xsh = xsh; |
| 243 | |
| 244 | notifier_list_init(&h->notifiers); |
| 245 | qemu_set_fd_handler(xs_fileno(h->xsh), watch_event, NULL, h); |
| 246 | |
| 247 | return h; |
| 248 | } |
| 249 | |
| 250 | static void libxenstore_close(struct qemu_xs_handle *h) |
| 251 | { |
| 252 | g_assert(notifier_list_empty(&h->notifiers)); |
| 253 | qemu_set_fd_handler(xs_fileno(h->xsh), NULL, NULL, NULL); |
| 254 | xs_close(h->xsh); |
| 255 | g_free(h); |
| 256 | } |
| 257 | |
| 258 | static char *libxenstore_get_domain_path(struct qemu_xs_handle *h, |
| 259 | unsigned int domid) |
| 260 | { |
| 261 | return xs_get_domain_path(h->xsh, domid); |
| 262 | } |
| 263 | |
| 264 | static char **libxenstore_directory(struct qemu_xs_handle *h, |
| 265 | xs_transaction_t t, const char *path, |
| 266 | unsigned int *num) |
| 267 | { |
| 268 | return xs_directory(h->xsh, t, path, num); |
| 269 | } |
| 270 | |
| 271 | static void *libxenstore_read(struct qemu_xs_handle *h, xs_transaction_t t, |
| 272 | const char *path, unsigned int *len) |
| 273 | { |
| 274 | return xs_read(h->xsh, t, path, len); |
| 275 | } |
| 276 | |
| 277 | static bool libxenstore_write(struct qemu_xs_handle *h, xs_transaction_t t, |
| 278 | const char *path, const void *data, |
| 279 | unsigned int len) |
| 280 | { |
| 281 | return xs_write(h->xsh, t, path, data, len); |
| 282 | } |
| 283 | |
| 284 | static bool libxenstore_create(struct qemu_xs_handle *h, xs_transaction_t t, |
| 285 | unsigned int owner, unsigned int domid, |
| 286 | unsigned int perms, const char *path) |
| 287 | { |
| 288 | struct xs_permissions perms_list[] = { |
| 289 | { |
| 290 | .id = owner, |
| 291 | .perms = XS_PERM_NONE, |
| 292 | }, |
| 293 | { |
| 294 | .id = domid, |
| 295 | .perms = perms, |
| 296 | }, |
| 297 | }; |
| 298 | |
| 299 | if (!xs_mkdir(h->xsh, t, path)) { |
| 300 | return false; |
| 301 | } |
| 302 | |
| 303 | return xs_set_permissions(h->xsh, t, path, perms_list, |
| 304 | ARRAY_SIZE(perms_list)); |
| 305 | } |
| 306 | |
| 307 | static bool libxenstore_destroy(struct qemu_xs_handle *h, xs_transaction_t t, |
| 308 | const char *path) |
| 309 | { |
| 310 | return xs_rm(h->xsh, t, path); |
| 311 | } |
| 312 | |
| 313 | struct qemu_xs_watch { |
| 314 | char *path; |
| 315 | char *token; |
| 316 | xs_watch_fn fn; |
| 317 | void *opaque; |
| 318 | Notifier notifier; |
| 319 | }; |
| 320 | |
| 321 | static void watch_notify(Notifier *n, void *data) |
| 322 | { |
| 323 | struct qemu_xs_watch *w = container_of(n, struct qemu_xs_watch, notifier); |
| 324 | const char **v = data; |
| 325 | |
| 326 | if (!strcmp(w->token, v[XS_WATCH_TOKEN])) { |
| 327 | w->fn(w->opaque, v[XS_WATCH_PATH]); |
| 328 | } |
| 329 | } |
| 330 | |
| 331 | static struct qemu_xs_watch *new_watch(const char *path, xs_watch_fn fn, |
| 332 | void *opaque) |
| 333 | { |
| 334 | struct qemu_xs_watch *w = g_new0(struct qemu_xs_watch, 1); |
| 335 | QemuUUID uuid; |
| 336 | |
| 337 | qemu_uuid_generate(&uuid); |
| 338 | |
| 339 | w->token = qemu_uuid_unparse_strdup(&uuid); |
| 340 | w->path = g_strdup(path); |
| 341 | w->fn = fn; |
| 342 | w->opaque = opaque; |
| 343 | w->notifier.notify = watch_notify; |
| 344 | |
| 345 | return w; |
| 346 | } |
| 347 | |
| 348 | static void free_watch(struct qemu_xs_watch *w) |
| 349 | { |
| 350 | g_free(w->token); |
| 351 | g_free(w->path); |
| 352 | |
| 353 | g_free(w); |
| 354 | } |
| 355 | |
| 356 | static struct qemu_xs_watch *libxenstore_watch(struct qemu_xs_handle *h, |
| 357 | const char *path, xs_watch_fn fn, |
| 358 | void *opaque) |
| 359 | { |
| 360 | struct qemu_xs_watch *w = new_watch(path, fn, opaque); |
| 361 | |
| 362 | notifier_list_add(&h->notifiers, &w->notifier); |
| 363 | |
| 364 | if (!xs_watch(h->xsh, path, w->token)) { |
| 365 | notifier_remove(&w->notifier); |
| 366 | free_watch(w); |
| 367 | return NULL; |
| 368 | } |
| 369 | |
| 370 | return w; |
| 371 | } |
| 372 | |
| 373 | static void libxenstore_unwatch(struct qemu_xs_handle *h, |
| 374 | struct qemu_xs_watch *w) |
| 375 | { |
| 376 | xs_unwatch(h->xsh, w->path, w->token); |
| 377 | notifier_remove(&w->notifier); |
| 378 | free_watch(w); |
| 379 | } |
| 380 | |
| 381 | static xs_transaction_t libxenstore_transaction_start(struct qemu_xs_handle *h) |
| 382 | { |
| 383 | return xs_transaction_start(h->xsh); |
| 384 | } |
| 385 | |
| 386 | static bool libxenstore_transaction_end(struct qemu_xs_handle *h, |
| 387 | xs_transaction_t t, bool abort) |
| 388 | { |
| 389 | return xs_transaction_end(h->xsh, t, abort); |
| 390 | } |
| 391 | |
| 392 | struct xenstore_backend_ops libxenstore_backend_ops = { |
| 393 | .open = libxenstore_open, |
| 394 | .close = libxenstore_close, |
| 395 | .get_domain_path = libxenstore_get_domain_path, |
| 396 | .directory = libxenstore_directory, |
| 397 | .read = libxenstore_read, |
| 398 | .write = libxenstore_write, |
| 399 | .create = libxenstore_create, |
| 400 | .destroy = libxenstore_destroy, |
| 401 | .watch = libxenstore_watch, |
| 402 | .unwatch = libxenstore_unwatch, |
| 403 | .transaction_start = libxenstore_transaction_start, |
| 404 | .transaction_end = libxenstore_transaction_end, |
| 405 | }; |
| 406 | |
| 407 | void setup_xen_backend_ops(void) |
| 408 | { |
| 409 | #if CONFIG_XEN_CTRL_INTERFACE_VERSION >= 40800 |
| 410 | xengnttab_handle *xgt = xengnttab_open(NULL, 0); |
| 411 | |
| 412 | if (xgt) { |
| 413 | if (xengnttab_grant_copy(xgt, 0, NULL) == 0) { |
| 414 | libxengnttab_backend_ops.grant_copy = libxengnttab_backend_grant_copy; |
| 415 | } |
| 416 | xengnttab_close(xgt); |
| 417 | } |
| 418 | #endif |
| 419 | xen_evtchn_ops = &libxenevtchn_backend_ops; |
| 420 | xen_gnttab_ops = &libxengnttab_backend_ops; |
| 421 | xen_foreignmem_ops = &libxenforeignmem_backend_ops; |
| 422 | xen_xenstore_ops = &libxenstore_backend_ops; |
| 423 | } |