1 | /* $NetBSD: xbd_xenbus.c,v 1.75 2015/10/25 07:51:16 maxv Exp $ */ |
2 | |
3 | /* |
4 | * Copyright (c) 2006 Manuel Bouyer. |
5 | * |
6 | * Redistribution and use in source and binary forms, with or without |
7 | * modification, are permitted provided that the following conditions |
8 | * are met: |
9 | * 1. Redistributions of source code must retain the above copyright |
10 | * notice, this list of conditions and the following disclaimer. |
11 | * 2. Redistributions in binary form must reproduce the above copyright |
12 | * notice, this list of conditions and the following disclaimer in the |
13 | * documentation and/or other materials provided with the distribution. |
14 | * |
15 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
16 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
17 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
18 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
19 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
20 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
21 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
22 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
23 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
24 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
25 | * |
26 | */ |
27 | |
28 | /* |
29 | * The file contains the xbd frontend code required for block-level |
30 | * communications (similar to hard disks) between two Xen domains. |
31 | * |
32 | * We are not supposed to receive solicitations spontaneously from backend. The |
33 | * protocol is therefore fairly simple and uses only one ring to communicate |
34 | * with backend: frontend posts requests to the ring then wait for their |
35 | * replies asynchronously. |
36 | * |
37 | * xbd follows NetBSD's disk(9) convention. At any time, a LWP can schedule |
38 | * an operation request for the device (be it open(), read(), write(), ...). |
39 | * Calls are typically processed that way: |
40 | * - initiate request: xbdread/write/open/ioctl/.. |
41 | * - depending on operation, it is handled directly by disk(9) subsystem or |
42 | * goes through physio(9) first. |
43 | * - the request is ultimately processed by xbd_diskstart() that prepares the |
44 | * xbd requests, post them in the ring I/O queue, then signal the backend. |
45 | * |
46 | * When a response is available in the queue, the backend signals the frontend |
47 | * via its event channel. This triggers xbd_handler(), which will link back |
48 | * the response to its request through the request ID, and mark the I/O as |
49 | * completed. |
50 | */ |
51 | |
52 | #include <sys/cdefs.h> |
53 | __KERNEL_RCSID(0, "$NetBSD: xbd_xenbus.c,v 1.75 2015/10/25 07:51:16 maxv Exp $" ); |
54 | |
55 | #include "opt_xen.h" |
56 | |
57 | |
58 | #include <sys/param.h> |
59 | #include <sys/buf.h> |
60 | #include <sys/bufq.h> |
61 | #include <sys/device.h> |
62 | #include <sys/disk.h> |
63 | #include <sys/disklabel.h> |
64 | #include <sys/conf.h> |
65 | #include <sys/fcntl.h> |
66 | #include <sys/kernel.h> |
67 | #include <sys/proc.h> |
68 | #include <sys/systm.h> |
69 | #include <sys/stat.h> |
70 | #include <sys/vnode.h> |
71 | |
72 | #include <dev/dkvar.h> |
73 | |
74 | #include <uvm/uvm.h> |
75 | |
76 | #include <xen/hypervisor.h> |
77 | #include <xen/evtchn.h> |
78 | #include <xen/granttables.h> |
79 | #include <xen/xen-public/io/blkif.h> |
80 | #include <xen/xen-public/io/protocols.h> |
81 | |
82 | #include <xen/xenbus.h> |
83 | #include "locators.h" |
84 | |
85 | #undef XBD_DEBUG |
86 | #ifdef XBD_DEBUG |
87 | #define DPRINTF(x) printf x; |
88 | #else |
89 | #define DPRINTF(x) |
90 | #endif |
91 | |
92 | #define GRANT_INVALID_REF -1 |
93 | |
94 | #define XBD_RING_SIZE __CONST_RING_SIZE(blkif, PAGE_SIZE) |
95 | #define XBD_MAX_XFER (PAGE_SIZE * BLKIF_MAX_SEGMENTS_PER_REQUEST) |
96 | |
97 | #define XEN_BSHIFT 9 /* log2(XEN_BSIZE) */ |
98 | #define XEN_BSIZE (1 << XEN_BSHIFT) |
99 | |
100 | struct xbd_req { |
101 | SLIST_ENTRY(xbd_req) req_next; |
102 | uint16_t req_id; /* ID passed to backend */ |
103 | union { |
104 | struct { |
105 | grant_ref_t req_gntref[BLKIF_MAX_SEGMENTS_PER_REQUEST]; |
106 | int req_nr_segments; /* number of segments in this request */ |
107 | struct buf *req_bp; /* buffer associated with this request */ |
108 | void *req_data; /* pointer to the data buffer */ |
109 | } req_rw; |
110 | struct { |
111 | int s_error; |
112 | volatile int s_done; |
113 | } req_sync; |
114 | } u; |
115 | }; |
116 | #define req_gntref u.req_rw.req_gntref |
117 | #define req_nr_segments u.req_rw.req_nr_segments |
118 | #define req_bp u.req_rw.req_bp |
119 | #define req_data u.req_rw.req_data |
120 | #define req_sync u.req_sync |
121 | |
122 | struct xbd_xenbus_softc { |
123 | struct dk_softc sc_dksc; /* Must be first in this struct */ |
124 | struct xenbus_device *sc_xbusd; |
125 | |
126 | blkif_front_ring_t sc_ring; |
127 | |
128 | unsigned int sc_evtchn; |
129 | |
130 | grant_ref_t sc_ring_gntref; |
131 | |
132 | struct xbd_req sc_reqs[XBD_RING_SIZE]; |
133 | SLIST_HEAD(,xbd_req) sc_xbdreq_head; /* list of free requests */ |
134 | bool sc_xbdreq_wait; /* special waiting on xbd_req */ |
135 | |
136 | int sc_backend_status; /* our status with backend */ |
137 | #define BLKIF_STATE_DISCONNECTED 0 |
138 | #define BLKIF_STATE_CONNECTED 1 |
139 | #define BLKIF_STATE_SUSPENDED 2 |
140 | |
141 | int sc_shutdown; |
142 | #define BLKIF_SHUTDOWN_RUN 0 /* no shutdown */ |
143 | #define BLKIF_SHUTDOWN_REMOTE 1 /* backend-initiated shutdown in progress */ |
144 | #define BLKIF_SHUTDOWN_LOCAL 2 /* locally-initiated shutdown in progress */ |
145 | |
146 | uint64_t sc_sectors; /* number of sectors for this device */ |
147 | u_long sc_secsize; /* sector size */ |
148 | uint64_t sc_xbdsize; /* size of disk in DEV_BSIZE */ |
149 | u_long sc_info; /* VDISK_* */ |
150 | u_long sc_handle; /* from backend */ |
151 | int sc_cache_flush; /* backend supports BLKIF_OP_FLUSH_DISKCACHE */ |
152 | }; |
153 | |
154 | #if 0 |
155 | /* too big to be on stack */ |
156 | static multicall_entry_t rq_mcl[XBD_RING_SIZE+1]; |
157 | static paddr_t rq_pages[XBD_RING_SIZE]; |
158 | #endif |
159 | |
160 | static int xbd_xenbus_match(device_t, cfdata_t, void *); |
161 | static void xbd_xenbus_attach(device_t, device_t, void *); |
162 | static int xbd_xenbus_detach(device_t, int); |
163 | |
164 | static bool xbd_xenbus_suspend(device_t, const pmf_qual_t *); |
165 | static bool xbd_xenbus_resume(device_t, const pmf_qual_t *); |
166 | |
167 | static int xbd_handler(void *); |
168 | static int xbd_diskstart(device_t, struct buf *); |
169 | static void xbd_backend_changed(void *, XenbusState); |
170 | static void xbd_connect(struct xbd_xenbus_softc *); |
171 | |
172 | static int xbd_map_align(struct xbd_req *); |
173 | static void xbd_unmap_align(struct xbd_req *); |
174 | |
175 | static void xbdminphys(struct buf *); |
176 | |
177 | CFATTACH_DECL3_NEW(xbd, sizeof(struct xbd_xenbus_softc), |
178 | xbd_xenbus_match, xbd_xenbus_attach, xbd_xenbus_detach, NULL, NULL, NULL, |
179 | DVF_DETACH_SHUTDOWN); |
180 | |
181 | dev_type_open(xbdopen); |
182 | dev_type_close(xbdclose); |
183 | dev_type_read(xbdread); |
184 | dev_type_write(xbdwrite); |
185 | dev_type_ioctl(xbdioctl); |
186 | dev_type_strategy(xbdstrategy); |
187 | dev_type_dump(xbddump); |
188 | dev_type_size(xbdsize); |
189 | |
190 | const struct bdevsw xbd_bdevsw = { |
191 | .d_open = xbdopen, |
192 | .d_close = xbdclose, |
193 | .d_strategy = xbdstrategy, |
194 | .d_ioctl = xbdioctl, |
195 | .d_dump = xbddump, |
196 | .d_psize = xbdsize, |
197 | .d_discard = nodiscard, |
198 | .d_flag = D_DISK |
199 | }; |
200 | |
201 | const struct cdevsw xbd_cdevsw = { |
202 | .d_open = xbdopen, |
203 | .d_close = xbdclose, |
204 | .d_read = xbdread, |
205 | .d_write = xbdwrite, |
206 | .d_ioctl = xbdioctl, |
207 | .d_stop = nostop, |
208 | .d_tty = notty, |
209 | .d_poll = nopoll, |
210 | .d_mmap = nommap, |
211 | .d_kqfilter = nokqfilter, |
212 | .d_discard = nodiscard, |
213 | .d_flag = D_DISK |
214 | }; |
215 | |
216 | extern struct cfdriver xbd_cd; |
217 | |
218 | static struct dkdriver xbddkdriver = { |
219 | .d_strategy = xbdstrategy, |
220 | .d_minphys = xbdminphys, |
221 | .d_open = xbdopen, |
222 | .d_close = xbdclose, |
223 | .d_diskstart = xbd_diskstart, |
224 | }; |
225 | |
226 | static int |
227 | xbd_xenbus_match(device_t parent, cfdata_t match, void *aux) |
228 | { |
229 | struct xenbusdev_attach_args *xa = aux; |
230 | |
231 | if (strcmp(xa->xa_type, "vbd" ) != 0) |
232 | return 0; |
233 | |
234 | if (match->cf_loc[XENBUSCF_ID] != XENBUSCF_ID_DEFAULT && |
235 | match->cf_loc[XENBUSCF_ID] != xa->xa_id) |
236 | return 0; |
237 | |
238 | return 1; |
239 | } |
240 | |
241 | static void |
242 | xbd_xenbus_attach(device_t parent, device_t self, void *aux) |
243 | { |
244 | struct xbd_xenbus_softc *sc = device_private(self); |
245 | struct xenbusdev_attach_args *xa = aux; |
246 | blkif_sring_t *ring; |
247 | RING_IDX i; |
248 | #ifdef XBD_DEBUG |
249 | char **dir, *val; |
250 | int dir_n = 0; |
251 | char id_str[20]; |
252 | int err; |
253 | #endif |
254 | |
255 | config_pending_incr(self); |
256 | aprint_normal(": Xen Virtual Block Device Interface\n" ); |
257 | |
258 | dk_init(&sc->sc_dksc, self, DKTYPE_ESDI); |
259 | disk_init(&sc->sc_dksc.sc_dkdev, device_xname(self), &xbddkdriver); |
260 | |
261 | #ifdef XBD_DEBUG |
262 | printf("path: %s\n" , xa->xa_xbusd->xbusd_path); |
263 | snprintf(id_str, sizeof(id_str), "%d" , xa->xa_id); |
264 | err = xenbus_directory(NULL, "device/vbd" , id_str, &dir_n, &dir); |
265 | if (err) { |
266 | aprint_error_dev(self, "xenbus_directory err %d\n" , err); |
267 | } else { |
268 | printf("%s/\n" , xa->xa_xbusd->xbusd_path); |
269 | for (i = 0; i < dir_n; i++) { |
270 | printf("\t/%s" , dir[i]); |
271 | err = xenbus_read(NULL, xa->xa_xbusd->xbusd_path, |
272 | dir[i], NULL, &val); |
273 | if (err) { |
274 | aprint_error_dev(self, "xenbus_read err %d\n" , |
275 | err); |
276 | } else { |
277 | printf(" = %s\n" , val); |
278 | free(val, M_DEVBUF); |
279 | } |
280 | } |
281 | } |
282 | #endif /* XBD_DEBUG */ |
283 | sc->sc_xbusd = xa->xa_xbusd; |
284 | sc->sc_xbusd->xbusd_otherend_changed = xbd_backend_changed; |
285 | |
286 | /* initialize free requests list */ |
287 | SLIST_INIT(&sc->sc_xbdreq_head); |
288 | for (i = 0; i < XBD_RING_SIZE; i++) { |
289 | sc->sc_reqs[i].req_id = i; |
290 | SLIST_INSERT_HEAD(&sc->sc_xbdreq_head, &sc->sc_reqs[i], |
291 | req_next); |
292 | } |
293 | |
294 | sc->sc_backend_status = BLKIF_STATE_DISCONNECTED; |
295 | sc->sc_shutdown = BLKIF_SHUTDOWN_REMOTE; |
296 | |
297 | ring = (void *)uvm_km_alloc(kernel_map, PAGE_SIZE, 0, UVM_KMF_WIRED); |
298 | if (ring == NULL) |
299 | panic("%s: can't alloc ring" , device_xname(self)); |
300 | sc->sc_ring.sring = ring; |
301 | |
302 | /* resume shared structures and tell backend that we are ready */ |
303 | if (xbd_xenbus_resume(self, PMF_Q_NONE) == false) { |
304 | uvm_km_free(kernel_map, (vaddr_t)ring, PAGE_SIZE, |
305 | UVM_KMF_WIRED); |
306 | return; |
307 | } |
308 | |
309 | if (!pmf_device_register(self, xbd_xenbus_suspend, xbd_xenbus_resume)) |
310 | aprint_error_dev(self, "couldn't establish power handler\n" ); |
311 | |
312 | } |
313 | |
314 | static int |
315 | xbd_xenbus_detach(device_t dev, int flags) |
316 | { |
317 | struct xbd_xenbus_softc *sc = device_private(dev); |
318 | int bmaj, cmaj, i, mn, rc, s; |
319 | |
320 | rc = disk_begindetach(&sc->sc_dksc.sc_dkdev, NULL, dev, flags); |
321 | if (rc != 0) |
322 | return rc; |
323 | |
324 | s = splbio(); |
325 | DPRINTF(("%s: xbd_detach\n" , device_xname(dev))); |
326 | if (sc->sc_shutdown == BLKIF_SHUTDOWN_RUN) { |
327 | sc->sc_shutdown = BLKIF_SHUTDOWN_LOCAL; |
328 | /* wait for requests to complete */ |
329 | while (sc->sc_backend_status == BLKIF_STATE_CONNECTED && |
330 | sc->sc_dksc.sc_dkdev.dk_stats->io_busy > 0) |
331 | tsleep(xbd_xenbus_detach, PRIBIO, "xbddetach" , hz/2); |
332 | |
333 | xenbus_switch_state(sc->sc_xbusd, NULL, XenbusStateClosing); |
334 | } |
335 | if ((flags & DETACH_FORCE) == 0) { |
336 | /* xbd_xenbus_detach already in progress */ |
337 | wakeup(xbd_xenbus_detach); |
338 | splx(s); |
339 | return EALREADY; |
340 | } |
341 | while (xenbus_read_driver_state(sc->sc_xbusd->xbusd_otherend) |
342 | != XenbusStateClosed) |
343 | tsleep(xbd_xenbus_detach, PRIBIO, "xbddetach2" , hz/2); |
344 | splx(s); |
345 | |
346 | /* locate the major number */ |
347 | bmaj = bdevsw_lookup_major(&xbd_bdevsw); |
348 | cmaj = cdevsw_lookup_major(&xbd_cdevsw); |
349 | |
350 | /* Nuke the vnodes for any open instances. */ |
351 | for (i = 0; i < MAXPARTITIONS; i++) { |
352 | mn = DISKMINOR(device_unit(dev), i); |
353 | vdevgone(bmaj, mn, mn, VBLK); |
354 | vdevgone(cmaj, mn, mn, VCHR); |
355 | } |
356 | if (sc->sc_backend_status == BLKIF_STATE_CONNECTED) { |
357 | /* Delete all of our wedges. */ |
358 | dkwedge_delall(&sc->sc_dksc.sc_dkdev); |
359 | |
360 | /* Kill off any queued buffers. */ |
361 | dk_drain(&sc->sc_dksc); |
362 | bufq_free(sc->sc_dksc.sc_bufq); |
363 | |
364 | /* detach disk */ |
365 | disk_detach(&sc->sc_dksc.sc_dkdev); |
366 | disk_destroy(&sc->sc_dksc.sc_dkdev); |
367 | dk_detach(&sc->sc_dksc); |
368 | } |
369 | |
370 | hypervisor_mask_event(sc->sc_evtchn); |
371 | event_remove_handler(sc->sc_evtchn, &xbd_handler, sc); |
372 | while (xengnt_status(sc->sc_ring_gntref)) { |
373 | tsleep(xbd_xenbus_detach, PRIBIO, "xbd_ref" , hz/2); |
374 | } |
375 | xengnt_revoke_access(sc->sc_ring_gntref); |
376 | uvm_km_free(kernel_map, (vaddr_t)sc->sc_ring.sring, |
377 | PAGE_SIZE, UVM_KMF_WIRED); |
378 | |
379 | pmf_device_deregister(dev); |
380 | |
381 | return 0; |
382 | } |
383 | |
384 | static bool |
385 | xbd_xenbus_suspend(device_t dev, const pmf_qual_t *qual) { |
386 | |
387 | int s; |
388 | struct xbd_xenbus_softc *sc; |
389 | |
390 | sc = device_private(dev); |
391 | |
392 | s = splbio(); |
393 | /* wait for requests to complete, then suspend device */ |
394 | while (sc->sc_backend_status == BLKIF_STATE_CONNECTED && |
395 | sc->sc_dksc.sc_dkdev.dk_stats->io_busy > 0) |
396 | tsleep(xbd_xenbus_suspend, PRIBIO, "xbdsuspend" , hz/2); |
397 | |
398 | hypervisor_mask_event(sc->sc_evtchn); |
399 | sc->sc_backend_status = BLKIF_STATE_SUSPENDED; |
400 | event_remove_handler(sc->sc_evtchn, xbd_handler, sc); |
401 | |
402 | splx(s); |
403 | |
404 | xenbus_device_suspend(sc->sc_xbusd); |
405 | aprint_verbose_dev(dev, "removed event channel %d\n" , sc->sc_evtchn); |
406 | |
407 | return true; |
408 | } |
409 | |
410 | static bool |
411 | xbd_xenbus_resume(device_t dev, const pmf_qual_t *qual) |
412 | { |
413 | struct xbd_xenbus_softc *sc; |
414 | struct xenbus_transaction *xbt; |
415 | int error; |
416 | blkif_sring_t *ring; |
417 | paddr_t ma; |
418 | const char *errmsg; |
419 | |
420 | sc = device_private(dev); |
421 | |
422 | if (sc->sc_backend_status == BLKIF_STATE_SUSPENDED) { |
423 | /* |
424 | * Device was suspended, so ensure that access associated to |
425 | * the block I/O ring is revoked. |
426 | */ |
427 | xengnt_revoke_access(sc->sc_ring_gntref); |
428 | } |
429 | sc->sc_ring_gntref = GRANT_INVALID_REF; |
430 | |
431 | /* Initialize ring */ |
432 | ring = sc->sc_ring.sring; |
433 | memset(ring, 0, PAGE_SIZE); |
434 | SHARED_RING_INIT(ring); |
435 | FRONT_RING_INIT(&sc->sc_ring, ring, PAGE_SIZE); |
436 | |
437 | /* |
438 | * get MA address of the ring, and use it to set up the grant entry |
439 | * for the block device |
440 | */ |
441 | (void)pmap_extract_ma(pmap_kernel(), (vaddr_t)ring, &ma); |
442 | error = xenbus_grant_ring(sc->sc_xbusd, ma, &sc->sc_ring_gntref); |
443 | if (error) |
444 | goto abort_resume; |
445 | |
446 | error = xenbus_alloc_evtchn(sc->sc_xbusd, &sc->sc_evtchn); |
447 | if (error) |
448 | goto abort_resume; |
449 | |
450 | aprint_verbose_dev(dev, "using event channel %d\n" , |
451 | sc->sc_evtchn); |
452 | event_set_handler(sc->sc_evtchn, &xbd_handler, sc, |
453 | IPL_BIO, device_xname(dev)); |
454 | |
455 | again: |
456 | xbt = xenbus_transaction_start(); |
457 | if (xbt == NULL) |
458 | return false; |
459 | error = xenbus_printf(xbt, sc->sc_xbusd->xbusd_path, |
460 | "ring-ref" ,"%u" , sc->sc_ring_gntref); |
461 | if (error) { |
462 | errmsg = "writing ring-ref" ; |
463 | goto abort_transaction; |
464 | } |
465 | error = xenbus_printf(xbt, sc->sc_xbusd->xbusd_path, |
466 | "event-channel" , "%u" , sc->sc_evtchn); |
467 | if (error) { |
468 | errmsg = "writing event channel" ; |
469 | goto abort_transaction; |
470 | } |
471 | error = xenbus_printf(xbt, sc->sc_xbusd->xbusd_path, |
472 | "protocol" , "%s" , XEN_IO_PROTO_ABI_NATIVE); |
473 | if (error) { |
474 | errmsg = "writing protocol" ; |
475 | goto abort_transaction; |
476 | } |
477 | error = xenbus_transaction_end(xbt, 0); |
478 | if (error == EAGAIN) |
479 | goto again; |
480 | if (error != 0) { |
481 | xenbus_dev_fatal(sc->sc_xbusd, error, |
482 | "completing transaction" ); |
483 | return false; |
484 | } |
485 | |
486 | xenbus_switch_state(sc->sc_xbusd, NULL, XenbusStateInitialised); |
487 | |
488 | if (sc->sc_backend_status == BLKIF_STATE_SUSPENDED) { |
489 | /* |
490 | * device was suspended, softc structures are |
491 | * already initialized - we use a shortcut |
492 | */ |
493 | sc->sc_backend_status = BLKIF_STATE_CONNECTED; |
494 | xenbus_device_resume(sc->sc_xbusd); |
495 | hypervisor_enable_event(sc->sc_evtchn); |
496 | xenbus_switch_state(sc->sc_xbusd, NULL, XenbusStateConnected); |
497 | } |
498 | |
499 | return true; |
500 | |
501 | abort_resume: |
502 | xenbus_dev_fatal(sc->sc_xbusd, error, "resuming device" ); |
503 | return false; |
504 | |
505 | abort_transaction: |
506 | xenbus_transaction_end(xbt, 1); |
507 | xenbus_dev_fatal(sc->sc_xbusd, error, "%s" , errmsg); |
508 | return false; |
509 | } |
510 | |
511 | static void xbd_backend_changed(void *arg, XenbusState new_state) |
512 | { |
513 | struct xbd_xenbus_softc *sc = device_private((device_t)arg); |
514 | struct disk_geom *dg; |
515 | |
516 | char buf[9]; |
517 | int s; |
518 | DPRINTF(("%s: new backend state %d\n" , |
519 | device_xname(sc->sc_dksc.sc_dev), new_state)); |
520 | |
521 | switch (new_state) { |
522 | case XenbusStateUnknown: |
523 | case XenbusStateInitialising: |
524 | case XenbusStateInitWait: |
525 | case XenbusStateInitialised: |
526 | break; |
527 | case XenbusStateClosing: |
528 | s = splbio(); |
529 | if (sc->sc_shutdown == BLKIF_SHUTDOWN_RUN) |
530 | sc->sc_shutdown = BLKIF_SHUTDOWN_REMOTE; |
531 | /* wait for requests to complete */ |
532 | while (sc->sc_backend_status == BLKIF_STATE_CONNECTED && |
533 | sc->sc_dksc.sc_dkdev.dk_stats->io_busy > 0) |
534 | tsleep(xbd_xenbus_detach, PRIBIO, "xbddetach" , hz/2); |
535 | splx(s); |
536 | xenbus_switch_state(sc->sc_xbusd, NULL, XenbusStateClosed); |
537 | break; |
538 | case XenbusStateConnected: |
539 | /* |
540 | * note that xbd_backend_changed() can only be called by |
541 | * the xenbus thread. |
542 | */ |
543 | |
544 | if (sc->sc_backend_status == BLKIF_STATE_CONNECTED || |
545 | sc->sc_backend_status == BLKIF_STATE_SUSPENDED) |
546 | /* already connected */ |
547 | return; |
548 | |
549 | xbd_connect(sc); |
550 | sc->sc_shutdown = BLKIF_SHUTDOWN_RUN; |
551 | hypervisor_enable_event(sc->sc_evtchn); |
552 | |
553 | sc->sc_xbdsize = |
554 | sc->sc_sectors * (uint64_t)sc->sc_secsize / DEV_BSIZE; |
555 | dg = &sc->sc_dksc.sc_dkdev.dk_geom; |
556 | memset(dg, 0, sizeof(*dg)); |
557 | |
558 | dg->dg_secperunit = sc->sc_xbdsize; |
559 | dg->dg_secsize = DEV_BSIZE; |
560 | dg->dg_ntracks = 1; |
561 | // XXX: Ok to hard-code DEV_BSIZE? |
562 | dg->dg_nsectors = 1024 * (1024 / dg->dg_secsize); |
563 | dg->dg_ncylinders = dg->dg_secperunit / dg->dg_nsectors; |
564 | |
565 | bufq_alloc(&sc->sc_dksc.sc_bufq, "fcfs" , 0); |
566 | dk_attach(&sc->sc_dksc); |
567 | disk_attach(&sc->sc_dksc.sc_dkdev); |
568 | |
569 | sc->sc_backend_status = BLKIF_STATE_CONNECTED; |
570 | |
571 | /* try to read the disklabel */ |
572 | dk_getdisklabel(&sc->sc_dksc, 0 /* XXX ? */); |
573 | format_bytes(buf, sizeof(buf), sc->sc_sectors * sc->sc_secsize); |
574 | aprint_verbose_dev(sc->sc_dksc.sc_dev, |
575 | "%s, %d bytes/sect x %" PRIu64 " sectors\n" , |
576 | buf, (int)dg->dg_secsize, sc->sc_xbdsize); |
577 | /* Discover wedges on this disk. */ |
578 | dkwedge_discover(&sc->sc_dksc.sc_dkdev); |
579 | |
580 | disk_set_info(sc->sc_dksc.sc_dev, &sc->sc_dksc.sc_dkdev, NULL); |
581 | |
582 | /* the disk should be working now */ |
583 | config_pending_decr(sc->sc_dksc.sc_dev); |
584 | break; |
585 | default: |
586 | panic("bad backend state %d" , new_state); |
587 | } |
588 | } |
589 | |
590 | static void |
591 | xbd_connect(struct xbd_xenbus_softc *sc) |
592 | { |
593 | int err; |
594 | unsigned long long sectors; |
595 | u_long cache_flush; |
596 | |
597 | err = xenbus_read_ul(NULL, |
598 | sc->sc_xbusd->xbusd_path, "virtual-device" , &sc->sc_handle, 10); |
599 | if (err) |
600 | panic("%s: can't read number from %s/virtual-device\n" , |
601 | device_xname(sc->sc_dksc.sc_dev), |
602 | sc->sc_xbusd->xbusd_otherend); |
603 | err = xenbus_read_ull(NULL, |
604 | sc->sc_xbusd->xbusd_otherend, "sectors" , §ors, 10); |
605 | if (err) |
606 | panic("%s: can't read number from %s/sectors\n" , |
607 | device_xname(sc->sc_dksc.sc_dev), |
608 | sc->sc_xbusd->xbusd_otherend); |
609 | sc->sc_sectors = sectors; |
610 | |
611 | err = xenbus_read_ul(NULL, |
612 | sc->sc_xbusd->xbusd_otherend, "info" , &sc->sc_info, 10); |
613 | if (err) |
614 | panic("%s: can't read number from %s/info\n" , |
615 | device_xname(sc->sc_dksc.sc_dev), |
616 | sc->sc_xbusd->xbusd_otherend); |
617 | err = xenbus_read_ul(NULL, |
618 | sc->sc_xbusd->xbusd_otherend, "sector-size" , &sc->sc_secsize, 10); |
619 | if (err) |
620 | panic("%s: can't read number from %s/sector-size\n" , |
621 | device_xname(sc->sc_dksc.sc_dev), |
622 | sc->sc_xbusd->xbusd_otherend); |
623 | |
624 | err = xenbus_read_ul(NULL, sc->sc_xbusd->xbusd_otherend, |
625 | "feature-flush-cache" , &cache_flush, 10); |
626 | if (err) |
627 | cache_flush = 0; |
628 | if (cache_flush > 0) |
629 | sc->sc_cache_flush = 1; |
630 | else |
631 | sc->sc_cache_flush = 0; |
632 | |
633 | xenbus_switch_state(sc->sc_xbusd, NULL, XenbusStateConnected); |
634 | } |
635 | |
636 | static int |
637 | xbd_handler(void *arg) |
638 | { |
639 | struct xbd_xenbus_softc *sc = arg; |
640 | struct buf *bp; |
641 | RING_IDX resp_prod, i; |
642 | int more_to_do; |
643 | int seg; |
644 | |
645 | DPRINTF(("xbd_handler(%s)\n" , device_xname(sc->sc_dksc.sc_dev))); |
646 | |
647 | if (__predict_false(sc->sc_backend_status != BLKIF_STATE_CONNECTED)) |
648 | return 0; |
649 | again: |
650 | resp_prod = sc->sc_ring.sring->rsp_prod; |
651 | xen_rmb(); /* ensure we see replies up to resp_prod */ |
652 | for (i = sc->sc_ring.rsp_cons; i != resp_prod; i++) { |
653 | blkif_response_t *rep = RING_GET_RESPONSE(&sc->sc_ring, i); |
654 | struct xbd_req *xbdreq = &sc->sc_reqs[rep->id]; |
655 | bp = xbdreq->req_bp; |
656 | DPRINTF(("xbd_handler(%p): b_bcount = %ld\n" , |
657 | xbdreq->req_bp, (long)bp->b_bcount)); |
658 | if (rep->operation == BLKIF_OP_FLUSH_DISKCACHE) { |
659 | xbdreq->req_sync.s_error = rep->status; |
660 | xbdreq->req_sync.s_done = 1; |
661 | wakeup(xbdreq); |
662 | /* caller will free the req */ |
663 | continue; |
664 | } |
665 | for (seg = xbdreq->req_nr_segments - 1; seg >= 0; seg--) { |
666 | if (__predict_false( |
667 | xengnt_status(xbdreq->req_gntref[seg]))) { |
668 | aprint_verbose_dev(sc->sc_dksc.sc_dev, |
669 | "grant still used by backend\n" ); |
670 | sc->sc_ring.rsp_cons = i; |
671 | xbdreq->req_nr_segments = seg + 1; |
672 | goto done; |
673 | } |
674 | xengnt_revoke_access(xbdreq->req_gntref[seg]); |
675 | xbdreq->req_nr_segments--; |
676 | } |
677 | if (rep->operation != BLKIF_OP_READ && |
678 | rep->operation != BLKIF_OP_WRITE) { |
679 | aprint_error_dev(sc->sc_dksc.sc_dev, |
680 | "bad operation %d from backend\n" , rep->operation); |
681 | bp->b_error = EIO; |
682 | bp->b_resid = bp->b_bcount; |
683 | goto next; |
684 | } |
685 | if (rep->status != BLKIF_RSP_OKAY) { |
686 | bp->b_error = EIO; |
687 | bp->b_resid = bp->b_bcount; |
688 | goto next; |
689 | } |
690 | /* b_resid was set in dk_start */ |
691 | next: |
692 | if (bp->b_data != xbdreq->req_data) |
693 | xbd_unmap_align(xbdreq); |
694 | |
695 | dk_done(&sc->sc_dksc, bp); |
696 | |
697 | SLIST_INSERT_HEAD(&sc->sc_xbdreq_head, xbdreq, req_next); |
698 | } |
699 | done: |
700 | xen_rmb(); |
701 | sc->sc_ring.rsp_cons = i; |
702 | |
703 | RING_FINAL_CHECK_FOR_RESPONSES(&sc->sc_ring, more_to_do); |
704 | if (more_to_do) |
705 | goto again; |
706 | |
707 | if (sc->sc_xbdreq_wait) |
708 | wakeup(&sc->sc_xbdreq_wait); |
709 | else |
710 | dk_start(&sc->sc_dksc, NULL); |
711 | return 1; |
712 | } |
713 | |
714 | static void |
715 | xbdminphys(struct buf *bp) |
716 | { |
717 | if (bp->b_bcount > XBD_MAX_XFER) { |
718 | bp->b_bcount = XBD_MAX_XFER; |
719 | } |
720 | minphys(bp); |
721 | } |
722 | |
723 | int |
724 | xbdopen(dev_t dev, int flags, int fmt, struct lwp *l) |
725 | { |
726 | struct xbd_xenbus_softc *sc; |
727 | |
728 | sc = device_lookup_private(&xbd_cd, DISKUNIT(dev)); |
729 | if (sc == NULL) |
730 | return (ENXIO); |
731 | if ((flags & FWRITE) && (sc->sc_info & VDISK_READONLY)) |
732 | return EROFS; |
733 | |
734 | DPRINTF(("xbdopen(0x%04x, %d)\n" , dev, flags)); |
735 | return dk_open(&sc->sc_dksc, dev, flags, fmt, l); |
736 | } |
737 | |
738 | int |
739 | xbdclose(dev_t dev, int flags, int fmt, struct lwp *l) |
740 | { |
741 | struct xbd_xenbus_softc *sc; |
742 | |
743 | sc = device_lookup_private(&xbd_cd, DISKUNIT(dev)); |
744 | |
745 | DPRINTF(("xbdclose(%d, %d)\n" , dev, flags)); |
746 | return dk_close(&sc->sc_dksc, dev, flags, fmt, l); |
747 | } |
748 | |
749 | void |
750 | xbdstrategy(struct buf *bp) |
751 | { |
752 | struct xbd_xenbus_softc *sc; |
753 | |
754 | sc = device_lookup_private(&xbd_cd, DISKUNIT(bp->b_dev)); |
755 | |
756 | DPRINTF(("xbdstrategy(%p): b_bcount = %ld\n" , bp, |
757 | (long)bp->b_bcount)); |
758 | |
759 | if (sc == NULL || sc->sc_shutdown != BLKIF_SHUTDOWN_RUN) { |
760 | bp->b_error = EIO; |
761 | biodone(bp); |
762 | return; |
763 | } |
764 | if (__predict_false((sc->sc_info & VDISK_READONLY) && |
765 | (bp->b_flags & B_READ) == 0)) { |
766 | bp->b_error = EROFS; |
767 | biodone(bp); |
768 | return; |
769 | } |
770 | |
771 | dk_strategy(&sc->sc_dksc, bp); |
772 | return; |
773 | } |
774 | |
775 | int |
776 | xbdsize(dev_t dev) |
777 | { |
778 | struct xbd_xenbus_softc *sc; |
779 | |
780 | DPRINTF(("xbdsize(%d)\n" , dev)); |
781 | |
782 | sc = device_lookup_private(&xbd_cd, DISKUNIT(dev)); |
783 | if (sc == NULL || sc->sc_shutdown != BLKIF_SHUTDOWN_RUN) |
784 | return -1; |
785 | return dk_size(&sc->sc_dksc, dev); |
786 | } |
787 | |
788 | int |
789 | xbdread(dev_t dev, struct uio *uio, int flags) |
790 | { |
791 | struct xbd_xenbus_softc *sc = |
792 | device_lookup_private(&xbd_cd, DISKUNIT(dev)); |
793 | struct dk_softc *dksc = &sc->sc_dksc; |
794 | |
795 | if (!DK_ATTACHED(dksc)) |
796 | return ENXIO; |
797 | return physio(xbdstrategy, NULL, dev, B_READ, xbdminphys, uio); |
798 | } |
799 | |
800 | int |
801 | xbdwrite(dev_t dev, struct uio *uio, int flags) |
802 | { |
803 | struct xbd_xenbus_softc *sc = |
804 | device_lookup_private(&xbd_cd, DISKUNIT(dev)); |
805 | struct dk_softc *dksc = &sc->sc_dksc; |
806 | |
807 | if (!DK_ATTACHED(dksc)) |
808 | return ENXIO; |
809 | if (__predict_false(sc->sc_info & VDISK_READONLY)) |
810 | return EROFS; |
811 | return physio(xbdstrategy, NULL, dev, B_WRITE, xbdminphys, uio); |
812 | } |
813 | |
814 | int |
815 | xbdioctl(dev_t dev, u_long cmd, void *data, int flag, struct lwp *l) |
816 | { |
817 | struct xbd_xenbus_softc *sc = |
818 | device_lookup_private(&xbd_cd, DISKUNIT(dev)); |
819 | struct dk_softc *dksc; |
820 | int error; |
821 | int s; |
822 | struct xbd_req *xbdreq; |
823 | blkif_request_t *req; |
824 | int notify; |
825 | |
826 | DPRINTF(("xbdioctl(%d, %08lx, %p, %d, %p)\n" , |
827 | dev, cmd, data, flag, l)); |
828 | dksc = &sc->sc_dksc; |
829 | |
830 | switch (cmd) { |
831 | case DIOCSSTRATEGY: |
832 | error = EOPNOTSUPP; |
833 | break; |
834 | case DIOCCACHESYNC: |
835 | if (sc->sc_cache_flush <= 0) { |
836 | if (sc->sc_cache_flush == 0) { |
837 | aprint_error_dev(sc->sc_dksc.sc_dev, |
838 | "WARNING: cache flush not supported " |
839 | "by backend\n" ); |
840 | sc->sc_cache_flush = -1; |
841 | } |
842 | return EOPNOTSUPP; |
843 | } |
844 | |
845 | s = splbio(); |
846 | |
847 | while (RING_FULL(&sc->sc_ring)) { |
848 | sc->sc_xbdreq_wait = 1; |
849 | tsleep(&sc->sc_xbdreq_wait, PRIBIO, "xbdreq" , 0); |
850 | } |
851 | sc->sc_xbdreq_wait = 0; |
852 | |
853 | xbdreq = SLIST_FIRST(&sc->sc_xbdreq_head); |
854 | if (__predict_false(xbdreq == NULL)) { |
855 | DPRINTF(("xbdioctl: no req\n" )); |
856 | error = ENOMEM; |
857 | } else { |
858 | SLIST_REMOVE_HEAD(&sc->sc_xbdreq_head, req_next); |
859 | req = RING_GET_REQUEST(&sc->sc_ring, |
860 | sc->sc_ring.req_prod_pvt); |
861 | req->id = xbdreq->req_id; |
862 | req->operation = BLKIF_OP_FLUSH_DISKCACHE; |
863 | req->handle = sc->sc_handle; |
864 | xbdreq->req_sync.s_done = 0; |
865 | sc->sc_ring.req_prod_pvt++; |
866 | RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&sc->sc_ring, |
867 | notify); |
868 | if (notify) |
869 | hypervisor_notify_via_evtchn(sc->sc_evtchn); |
870 | /* request sent, no wait for completion */ |
871 | while (xbdreq->req_sync.s_done == 0) { |
872 | tsleep(xbdreq, PRIBIO, "xbdsync" , 0); |
873 | } |
874 | if (xbdreq->req_sync.s_error == BLKIF_RSP_EOPNOTSUPP) |
875 | error = EOPNOTSUPP; |
876 | else if (xbdreq->req_sync.s_error == BLKIF_RSP_OKAY) |
877 | error = 0; |
878 | else |
879 | error = EIO; |
880 | SLIST_INSERT_HEAD(&sc->sc_xbdreq_head, xbdreq, |
881 | req_next); |
882 | } |
883 | splx(s); |
884 | break; |
885 | |
886 | default: |
887 | error = dk_ioctl(dksc, dev, cmd, data, flag, l); |
888 | break; |
889 | } |
890 | |
891 | return error; |
892 | } |
893 | |
894 | int |
895 | xbddump(dev_t dev, daddr_t blkno, void *va, size_t size) |
896 | { |
897 | struct xbd_xenbus_softc *sc; |
898 | |
899 | sc = device_lookup_private(&xbd_cd, DISKUNIT(dev)); |
900 | if (sc == NULL) |
901 | return (ENXIO); |
902 | |
903 | DPRINTF(("xbddump(%d, %" PRId64 ", %p, %lu)\n" , dev, blkno, va, |
904 | (unsigned long)size)); |
905 | return dk_dump(&sc->sc_dksc, dev, blkno, va, size); |
906 | } |
907 | |
908 | static int |
909 | xbd_diskstart(device_t self, struct buf *bp) |
910 | { |
911 | struct xbd_xenbus_softc *sc = device_private(self); |
912 | struct xbd_req *xbdreq; |
913 | blkif_request_t *req; |
914 | size_t bcount, off; |
915 | paddr_t ma; |
916 | vaddr_t va; |
917 | int nsects, nbytes, seg; |
918 | int notify, error = 0; |
919 | |
920 | DPRINTF(("xbd_diskstart(%p): b_bcount = %ld\n" , |
921 | bp, (long)bp->b_bcount)); |
922 | |
923 | if (sc->sc_shutdown != BLKIF_SHUTDOWN_RUN) { |
924 | error = EIO; |
925 | goto err; |
926 | } |
927 | |
928 | if (bp->b_rawblkno < 0 || bp->b_rawblkno > sc->sc_xbdsize) { |
929 | /* invalid block number */ |
930 | error = EINVAL; |
931 | goto err; |
932 | } |
933 | |
934 | if (__predict_false( |
935 | sc->sc_backend_status == BLKIF_STATE_SUSPENDED)) { |
936 | /* device is suspended, do not consume buffer */ |
937 | DPRINTF(("%s: (xbd_diskstart) device suspended\n" , |
938 | sc->sc_dksc.sc_xname)); |
939 | error = EAGAIN; |
940 | goto out; |
941 | } |
942 | |
943 | if (RING_FULL(&sc->sc_ring) || sc->sc_xbdreq_wait) { |
944 | DPRINTF(("xbd_diskstart: ring_full\n" )); |
945 | error = EAGAIN; |
946 | goto out; |
947 | } |
948 | |
949 | xbdreq = SLIST_FIRST(&sc->sc_xbdreq_head); |
950 | if (__predict_false(xbdreq == NULL)) { |
951 | DPRINTF(("xbd_diskstart: no req\n" )); |
952 | error = EAGAIN; |
953 | goto out; |
954 | } |
955 | |
956 | xbdreq->req_bp = bp; |
957 | xbdreq->req_data = bp->b_data; |
958 | if ((vaddr_t)bp->b_data & (XEN_BSIZE - 1)) { |
959 | if (__predict_false(xbd_map_align(xbdreq) != 0)) { |
960 | DPRINTF(("xbd_diskstart: no align\n" )); |
961 | error = EAGAIN; |
962 | goto out; |
963 | } |
964 | } |
965 | |
966 | SLIST_REMOVE_HEAD(&sc->sc_xbdreq_head, req_next); |
967 | req = RING_GET_REQUEST(&sc->sc_ring, sc->sc_ring.req_prod_pvt); |
968 | req->id = xbdreq->req_id; |
969 | req->operation = |
970 | bp->b_flags & B_READ ? BLKIF_OP_READ : BLKIF_OP_WRITE; |
971 | req->sector_number = bp->b_rawblkno; |
972 | req->handle = sc->sc_handle; |
973 | |
974 | va = (vaddr_t)xbdreq->req_data & ~PAGE_MASK; |
975 | off = (vaddr_t)xbdreq->req_data & PAGE_MASK; |
976 | bcount = bp->b_bcount; |
977 | bp->b_resid = 0; |
978 | for (seg = 0; bcount > 0;) { |
979 | pmap_extract_ma(pmap_kernel(), va, &ma); |
980 | KASSERT((ma & (XEN_BSIZE - 1)) == 0); |
981 | if (bcount > PAGE_SIZE - off) |
982 | nbytes = PAGE_SIZE - off; |
983 | else |
984 | nbytes = bcount; |
985 | nsects = nbytes >> XEN_BSHIFT; |
986 | req->seg[seg].first_sect = off >> XEN_BSHIFT; |
987 | req->seg[seg].last_sect = |
988 | (off >> XEN_BSHIFT) + nsects - 1; |
989 | KASSERT(req->seg[seg].first_sect <= |
990 | req->seg[seg].last_sect); |
991 | KASSERT(req->seg[seg].last_sect < 8); |
992 | if (__predict_false(xengnt_grant_access( |
993 | sc->sc_xbusd->xbusd_otherend_id, ma, |
994 | (bp->b_flags & B_READ) == 0, |
995 | &xbdreq->req_gntref[seg]))) |
996 | panic("xbd_diskstart: xengnt_grant_access" ); /* XXX XXX !!! */ |
997 | req->seg[seg].gref = xbdreq->req_gntref[seg]; |
998 | seg++; |
999 | KASSERT(seg <= BLKIF_MAX_SEGMENTS_PER_REQUEST); |
1000 | va += PAGE_SIZE; |
1001 | off = 0; |
1002 | bcount -= nbytes; |
1003 | } |
1004 | xbdreq->req_nr_segments = req->nr_segments = seg; |
1005 | sc->sc_ring.req_prod_pvt++; |
1006 | |
1007 | out: |
1008 | RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&sc->sc_ring, notify); |
1009 | if (notify) |
1010 | hypervisor_notify_via_evtchn(sc->sc_evtchn); |
1011 | err: |
1012 | return error; |
1013 | } |
1014 | |
1015 | static int |
1016 | xbd_map_align(struct xbd_req *req) |
1017 | { |
1018 | int s = splvm(); |
1019 | int rc; |
1020 | |
1021 | rc = uvm_km_kmem_alloc(kmem_va_arena, |
1022 | req->req_bp->b_bcount, (VM_NOSLEEP | VM_INSTANTFIT), |
1023 | (vmem_addr_t *)&req->req_data); |
1024 | splx(s); |
1025 | if (__predict_false(rc != 0)) |
1026 | return ENOMEM; |
1027 | if ((req->req_bp->b_flags & B_READ) == 0) |
1028 | memcpy(req->req_data, req->req_bp->b_data, |
1029 | req->req_bp->b_bcount); |
1030 | return 0; |
1031 | } |
1032 | |
1033 | static void |
1034 | xbd_unmap_align(struct xbd_req *req) |
1035 | { |
1036 | int s; |
1037 | if (req->req_bp->b_flags & B_READ) |
1038 | memcpy(req->req_bp->b_data, req->req_data, |
1039 | req->req_bp->b_bcount); |
1040 | s = splvm(); |
1041 | uvm_km_kmem_free(kmem_va_arena, (vaddr_t)req->req_data, req->req_bp->b_bcount); |
1042 | splx(s); |
1043 | } |
1044 | |