2 * XenBSD block device driver
4 * Copyright (c) 2010-2013 Spectra Logic Corporation
5 * Copyright (c) 2009 Scott Long, Yahoo!
6 * Copyright (c) 2009 Frank Suchomel, Citrix
7 * Copyright (c) 2009 Doug F. Rabson, Citrix
8 * Copyright (c) 2005 Kip Macy
9 * Copyright (c) 2003-2004, Keir Fraser & Steve Hand
10 * Modifications by Mark A. Williamson are (c) Intel Research Cambridge
13 * Permission is hereby granted, free of charge, to any person obtaining a copy
14 * of this software and associated documentation files (the "Software"), to
15 * deal in the Software without restriction, including without limitation the
16 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
17 * sell copies of the Software, and to permit persons to whom the Software is
18 * furnished to do so, subject to the following conditions:
20 * The above copyright notice and this permission notice shall be included in
21 * all copies or substantial portions of the Software.
22 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
23 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
24 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
25 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
26 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
27 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
28 * DEALINGS IN THE SOFTWARE.
31 #include <sys/cdefs.h>
32 __FBSDID("$FreeBSD$");
34 #include <sys/param.h>
35 #include <sys/systm.h>
36 #include <sys/malloc.h>
37 #include <sys/kernel.h>
44 #include <sys/module.h>
45 #include <sys/sysctl.h>
47 #include <machine/bus.h>
49 #include <machine/resource.h>
50 #include <machine/intr_machdep.h>
51 #include <machine/vmparam.h>
52 #include <sys/bus_dma.h>
54 #include <xen/xen-os.h>
55 #include <xen/hypervisor.h>
56 #include <xen/xen_intr.h>
57 #include <xen/gnttab.h>
58 #include <xen/interface/grant_table.h>
59 #include <xen/interface/io/protocols.h>
60 #include <xen/xenbus/xenbusvar.h>
62 #include <machine/_inttypes.h>
64 #include <geom/geom_disk.h>
66 #include <dev/xen/blkfront/block.h>
68 #include "xenbus_if.h"
70 /*--------------------------- Forward Declarations ---------------------------*/
71 static void xbd_closing(device_t);
72 static void xbd_startio(struct xbd_softc *sc);
74 /*---------------------------------- Macros ----------------------------------*/
76 #define DPRINTK(fmt, args...) printf("[XEN] %s:%d: " fmt ".\n", __func__, __LINE__, ##args)
78 #define DPRINTK(fmt, args...)
81 #define XBD_SECTOR_SHFT 9
83 /*---------------------------- Global Static Data ----------------------------*/
84 static MALLOC_DEFINE(M_XENBLOCKFRONT, "xbd", "Xen Block Front driver data");
86 static int xbd_enable_indirect = 1;
87 SYSCTL_NODE(_hw, OID_AUTO, xbd, CTLFLAG_RD, 0, "xbd driver parameters");
88 SYSCTL_INT(_hw_xbd, OID_AUTO, xbd_enable_indirect, CTLFLAG_RDTUN,
89 &xbd_enable_indirect, 0, "Enable xbd indirect segments");
91 /*---------------------------- Command Processing ----------------------------*/
93 xbd_freeze(struct xbd_softc *sc, xbd_flag_t xbd_flag)
95 if (xbd_flag != XBDF_NONE && (sc->xbd_flags & xbd_flag) != 0)
98 sc->xbd_flags |= xbd_flag;
99 sc->xbd_qfrozen_cnt++;
103 xbd_thaw(struct xbd_softc *sc, xbd_flag_t xbd_flag)
105 if (xbd_flag != XBDF_NONE && (sc->xbd_flags & xbd_flag) == 0)
108 if (sc->xbd_qfrozen_cnt == 0)
109 panic("%s: Thaw with flag 0x%x while not frozen.",
112 sc->xbd_flags &= ~xbd_flag;
113 sc->xbd_qfrozen_cnt--;
117 xbd_cm_freeze(struct xbd_softc *sc, struct xbd_command *cm, xbdc_flag_t cm_flag)
119 if ((cm->cm_flags & XBDCF_FROZEN) != 0)
122 cm->cm_flags |= XBDCF_FROZEN|cm_flag;
123 xbd_freeze(sc, XBDF_NONE);
127 xbd_cm_thaw(struct xbd_softc *sc, struct xbd_command *cm)
129 if ((cm->cm_flags & XBDCF_FROZEN) == 0)
132 cm->cm_flags &= ~XBDCF_FROZEN;
133 xbd_thaw(sc, XBDF_NONE);
137 xbd_flush_requests(struct xbd_softc *sc)
141 RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&sc->xbd_ring, notify);
144 xen_intr_signal(sc->xen_intr_handle);
148 xbd_free_command(struct xbd_command *cm)
151 KASSERT((cm->cm_flags & XBDCF_Q_MASK) == XBD_Q_NONE,
152 ("Freeing command that is still on queue %d.",
153 cm->cm_flags & XBDCF_Q_MASK));
155 cm->cm_flags = XBDCF_INITIALIZER;
157 cm->cm_complete = NULL;
158 xbd_enqueue_cm(cm, XBD_Q_FREE);
159 xbd_thaw(cm->cm_sc, XBDF_CM_SHORTAGE);
163 xbd_mksegarray(bus_dma_segment_t *segs, int nsegs,
164 grant_ref_t * gref_head, int otherend_id, int readonly,
165 grant_ref_t * sg_ref, struct blkif_request_segment *sg)
167 struct blkif_request_segment *last_block_sg = sg + nsegs;
168 vm_paddr_t buffer_ma;
169 uint64_t fsect, lsect;
172 while (sg < last_block_sg) {
173 buffer_ma = segs->ds_addr;
174 fsect = (buffer_ma & PAGE_MASK) >> XBD_SECTOR_SHFT;
175 lsect = fsect + (segs->ds_len >> XBD_SECTOR_SHFT) - 1;
177 KASSERT(lsect <= 7, ("XEN disk driver data cannot "
178 "cross a page boundary"));
180 /* install a grant reference. */
181 ref = gnttab_claim_grant_reference(gref_head);
184 * GNTTAB_LIST_END == 0xffffffff, but it is private
187 KASSERT(ref != ~0, ("grant_reference failed"));
189 gnttab_grant_foreign_access_ref(
192 buffer_ma >> PAGE_SHIFT,
196 *sg = (struct blkif_request_segment) {
208 xbd_queue_cb(void *arg, bus_dma_segment_t *segs, int nsegs, int error)
210 struct xbd_softc *sc;
211 struct xbd_command *cm;
218 cm->cm_bp->bio_error = EIO;
220 xbd_free_command(cm);
224 KASSERT(nsegs <= sc->xbd_max_request_segments,
225 ("Too many segments in a blkfront I/O"));
227 if (nsegs <= BLKIF_MAX_SEGMENTS_PER_REQUEST) {
228 blkif_request_t *ring_req;
230 /* Fill out a blkif_request_t structure. */
231 ring_req = (blkif_request_t *)
232 RING_GET_REQUEST(&sc->xbd_ring, sc->xbd_ring.req_prod_pvt);
233 sc->xbd_ring.req_prod_pvt++;
234 ring_req->id = cm->cm_id;
235 ring_req->operation = cm->cm_operation;
236 ring_req->sector_number = cm->cm_sector_number;
237 ring_req->handle = (blkif_vdev_t)(uintptr_t)sc->xbd_disk;
238 ring_req->nr_segments = nsegs;
240 xbd_mksegarray(segs, nsegs, &cm->cm_gref_head,
241 xenbus_get_otherend_id(sc->xbd_dev),
242 cm->cm_operation == BLKIF_OP_WRITE,
243 cm->cm_sg_refs, ring_req->seg);
245 blkif_request_indirect_t *ring_req;
247 /* Fill out a blkif_request_indirect_t structure. */
248 ring_req = (blkif_request_indirect_t *)
249 RING_GET_REQUEST(&sc->xbd_ring, sc->xbd_ring.req_prod_pvt);
250 sc->xbd_ring.req_prod_pvt++;
251 ring_req->id = cm->cm_id;
252 ring_req->operation = BLKIF_OP_INDIRECT;
253 ring_req->indirect_op = cm->cm_operation;
254 ring_req->sector_number = cm->cm_sector_number;
255 ring_req->handle = (blkif_vdev_t)(uintptr_t)sc->xbd_disk;
256 ring_req->nr_segments = nsegs;
258 xbd_mksegarray(segs, nsegs, &cm->cm_gref_head,
259 xenbus_get_otherend_id(sc->xbd_dev),
260 cm->cm_operation == BLKIF_OP_WRITE,
261 cm->cm_sg_refs, cm->cm_indirectionpages);
262 memcpy(ring_req->indirect_grefs, &cm->cm_indirectionrefs,
263 sizeof(grant_ref_t) * sc->xbd_max_request_indirectpages);
266 if (cm->cm_operation == BLKIF_OP_READ)
267 op = BUS_DMASYNC_PREREAD;
268 else if (cm->cm_operation == BLKIF_OP_WRITE)
269 op = BUS_DMASYNC_PREWRITE;
272 bus_dmamap_sync(sc->xbd_io_dmat, cm->cm_map, op);
274 gnttab_free_grant_references(cm->cm_gref_head);
276 xbd_enqueue_cm(cm, XBD_Q_BUSY);
279 * If bus dma had to asynchronously call us back to dispatch
280 * this command, we are no longer executing in the context of
281 * xbd_startio(). Thus we cannot rely on xbd_startio()'s call to
282 * xbd_flush_requests() to publish this command to the backend
283 * along with any other commands that it could batch.
285 if ((cm->cm_flags & XBDCF_ASYNC_MAPPING) != 0)
286 xbd_flush_requests(sc);
292 xbd_queue_request(struct xbd_softc *sc, struct xbd_command *cm)
296 error = bus_dmamap_load(sc->xbd_io_dmat, cm->cm_map, cm->cm_data,
297 cm->cm_datalen, xbd_queue_cb, cm, 0);
298 if (error == EINPROGRESS) {
300 * Maintain queuing order by freezing the queue. The next
301 * command may not require as many resources as the command
302 * we just attempted to map, so we can't rely on bus dma
303 * blocking for it too.
305 xbd_cm_freeze(sc, cm, XBDCF_ASYNC_MAPPING);
313 xbd_restart_queue_callback(void *arg)
315 struct xbd_softc *sc = arg;
317 mtx_lock(&sc->xbd_io_lock);
319 xbd_thaw(sc, XBDF_GNT_SHORTAGE);
323 mtx_unlock(&sc->xbd_io_lock);
326 static struct xbd_command *
327 xbd_bio_command(struct xbd_softc *sc)
329 struct xbd_command *cm;
332 if (__predict_false(sc->xbd_state != XBD_STATE_CONNECTED))
335 bp = xbd_dequeue_bio(sc);
339 if ((cm = xbd_dequeue_cm(sc, XBD_Q_FREE)) == NULL) {
340 xbd_freeze(sc, XBDF_CM_SHORTAGE);
341 xbd_requeue_bio(sc, bp);
345 if (gnttab_alloc_grant_references(sc->xbd_max_request_segments,
346 &cm->cm_gref_head) != 0) {
347 gnttab_request_free_callback(&sc->xbd_callback,
348 xbd_restart_queue_callback, sc,
349 sc->xbd_max_request_segments);
350 xbd_freeze(sc, XBDF_GNT_SHORTAGE);
351 xbd_requeue_bio(sc, bp);
352 xbd_enqueue_cm(cm, XBD_Q_FREE);
357 cm->cm_data = bp->bio_data;
358 cm->cm_datalen = bp->bio_bcount;
359 cm->cm_sector_number = (blkif_sector_t)bp->bio_pblkno;
361 switch (bp->bio_cmd) {
363 cm->cm_operation = BLKIF_OP_READ;
366 cm->cm_operation = BLKIF_OP_WRITE;
367 if ((bp->bio_flags & BIO_ORDERED) != 0) {
368 if ((sc->xbd_flags & XBDF_BARRIER) != 0) {
369 cm->cm_operation = BLKIF_OP_WRITE_BARRIER;
372 * Single step this command.
374 cm->cm_flags |= XBDCF_Q_FREEZE;
375 if (xbd_queue_length(sc, XBD_Q_BUSY) != 0) {
377 * Wait for in-flight requests to
380 xbd_freeze(sc, XBDF_WAIT_IDLE);
381 xbd_requeue_cm(cm, XBD_Q_READY);
388 if ((sc->xbd_flags & XBDF_FLUSH) != 0)
389 cm->cm_operation = BLKIF_OP_FLUSH_DISKCACHE;
390 else if ((sc->xbd_flags & XBDF_BARRIER) != 0)
391 cm->cm_operation = BLKIF_OP_WRITE_BARRIER;
393 panic("flush request, but no flush support available");
396 panic("unknown bio command %d", bp->bio_cmd);
403 * Dequeue buffers and place them in the shared communication ring.
404 * Return when no more requests can be accepted or all buffers have
407 * Signal XEN once the ring has been filled out.
410 xbd_startio(struct xbd_softc *sc)
412 struct xbd_command *cm;
413 int error, queued = 0;
415 mtx_assert(&sc->xbd_io_lock, MA_OWNED);
417 if (sc->xbd_state != XBD_STATE_CONNECTED)
420 while (!RING_FULL(&sc->xbd_ring)) {
422 if (sc->xbd_qfrozen_cnt != 0)
425 cm = xbd_dequeue_cm(sc, XBD_Q_READY);
428 cm = xbd_bio_command(sc);
433 if ((cm->cm_flags & XBDCF_Q_FREEZE) != 0) {
435 * Single step command. Future work is
436 * held off until this command completes.
438 xbd_cm_freeze(sc, cm, XBDCF_Q_FREEZE);
441 if ((error = xbd_queue_request(sc, cm)) != 0) {
442 printf("xbd_queue_request returned %d\n", error);
449 xbd_flush_requests(sc);
453 xbd_bio_complete(struct xbd_softc *sc, struct xbd_command *cm)
459 if (__predict_false(cm->cm_status != BLKIF_RSP_OKAY)) {
460 disk_err(bp, "disk error" , -1, 0);
461 printf(" status: %x\n", cm->cm_status);
462 bp->bio_flags |= BIO_ERROR;
465 if (bp->bio_flags & BIO_ERROR)
470 xbd_free_command(cm);
477 struct xbd_softc *sc = xsc;
478 struct xbd_command *cm;
479 blkif_response_t *bret;
483 mtx_lock(&sc->xbd_io_lock);
485 if (__predict_false(sc->xbd_state == XBD_STATE_DISCONNECTED)) {
486 mtx_unlock(&sc->xbd_io_lock);
491 rp = sc->xbd_ring.sring->rsp_prod;
492 rmb(); /* Ensure we see queued responses up to 'rp'. */
494 for (i = sc->xbd_ring.rsp_cons; i != rp;) {
495 bret = RING_GET_RESPONSE(&sc->xbd_ring, i);
496 cm = &sc->xbd_shadow[bret->id];
498 xbd_remove_cm(cm, XBD_Q_BUSY);
499 gnttab_end_foreign_access_references(cm->cm_nseg,
503 if (cm->cm_operation == BLKIF_OP_READ)
504 op = BUS_DMASYNC_POSTREAD;
505 else if (cm->cm_operation == BLKIF_OP_WRITE ||
506 cm->cm_operation == BLKIF_OP_WRITE_BARRIER)
507 op = BUS_DMASYNC_POSTWRITE;
510 bus_dmamap_sync(sc->xbd_io_dmat, cm->cm_map, op);
511 bus_dmamap_unload(sc->xbd_io_dmat, cm->cm_map);
514 * Release any hold this command has on future command
520 * Directly call the i/o complete routine to save an
521 * an indirection in the common case.
523 cm->cm_status = bret->status;
525 xbd_bio_complete(sc, cm);
526 else if (cm->cm_complete != NULL)
529 xbd_free_command(cm);
532 sc->xbd_ring.rsp_cons = i;
534 if (i != sc->xbd_ring.req_prod_pvt) {
536 RING_FINAL_CHECK_FOR_RESPONSES(&sc->xbd_ring, more_to_do);
540 sc->xbd_ring.sring->rsp_event = i + 1;
543 if (xbd_queue_length(sc, XBD_Q_BUSY) == 0)
544 xbd_thaw(sc, XBDF_WAIT_IDLE);
548 if (__predict_false(sc->xbd_state == XBD_STATE_SUSPENDED))
549 wakeup(&sc->xbd_cm_q[XBD_Q_BUSY]);
551 mtx_unlock(&sc->xbd_io_lock);
554 /*------------------------------- Dump Support -------------------------------*/
556 * Quiesce the disk writes for a dump file before allowing the next buffer.
559 xbd_quiesce(struct xbd_softc *sc)
563 // While there are outstanding requests
564 while (xbd_queue_length(sc, XBD_Q_BUSY) != 0) {
565 RING_FINAL_CHECK_FOR_RESPONSES(&sc->xbd_ring, mtd);
567 /* Recieved request completions, update queue. */
570 if (xbd_queue_length(sc, XBD_Q_BUSY) != 0) {
572 * Still pending requests, wait for the disk i/o
580 /* Kernel dump function for a paravirtualized disk device */
582 xbd_dump_complete(struct xbd_command *cm)
585 xbd_enqueue_cm(cm, XBD_Q_COMPLETE);
589 xbd_dump(void *arg, void *virtual, vm_offset_t physical, off_t offset,
592 struct disk *dp = arg;
593 struct xbd_softc *sc = dp->d_drv1;
594 struct xbd_command *cm;
602 xbd_quiesce(sc); /* All quiet on the western front. */
605 * If this lock is held, then this module is failing, and a
606 * successful kernel dump is highly unlikely anyway.
608 mtx_lock(&sc->xbd_io_lock);
610 /* Split the 64KB block as needed */
611 for (sbp=0; length > 0; sbp++) {
612 cm = xbd_dequeue_cm(sc, XBD_Q_FREE);
614 mtx_unlock(&sc->xbd_io_lock);
615 device_printf(sc->xbd_dev, "dump: no more commands?\n");
619 if (gnttab_alloc_grant_references(sc->xbd_max_request_segments,
620 &cm->cm_gref_head) != 0) {
621 xbd_free_command(cm);
622 mtx_unlock(&sc->xbd_io_lock);
623 device_printf(sc->xbd_dev, "no more grant allocs?\n");
627 chunk = length > sc->xbd_max_request_size ?
628 sc->xbd_max_request_size : length;
629 cm->cm_data = virtual;
630 cm->cm_datalen = chunk;
631 cm->cm_operation = BLKIF_OP_WRITE;
632 cm->cm_sector_number = offset / dp->d_sectorsize;
633 cm->cm_complete = xbd_dump_complete;
635 xbd_enqueue_cm(cm, XBD_Q_READY);
639 virtual = (char *) virtual + chunk;
642 /* Tell DOM0 to do the I/O */
644 mtx_unlock(&sc->xbd_io_lock);
646 /* Poll for the completion. */
647 xbd_quiesce(sc); /* All quite on the eastern front */
649 /* If there were any errors, bail out... */
650 while ((cm = xbd_dequeue_cm(sc, XBD_Q_COMPLETE)) != NULL) {
651 if (cm->cm_status != BLKIF_RSP_OKAY) {
652 device_printf(sc->xbd_dev,
653 "Dump I/O failed at sector %jd\n",
654 cm->cm_sector_number);
657 xbd_free_command(cm);
663 /*----------------------------- Disk Entrypoints -----------------------------*/
665 xbd_open(struct disk *dp)
667 struct xbd_softc *sc = dp->d_drv1;
670 printf("xb%d: not found", sc->xbd_unit);
674 sc->xbd_flags |= XBDF_OPEN;
680 xbd_close(struct disk *dp)
682 struct xbd_softc *sc = dp->d_drv1;
686 sc->xbd_flags &= ~XBDF_OPEN;
687 if (--(sc->xbd_users) == 0) {
689 * Check whether we have been instructed to close. We will
690 * have ignored this request initially, as the device was
693 if (xenbus_get_otherend_state(sc->xbd_dev) ==
695 xbd_closing(sc->xbd_dev);
701 xbd_ioctl(struct disk *dp, u_long cmd, void *addr, int flag, struct thread *td)
703 struct xbd_softc *sc = dp->d_drv1;
712 * Read/write routine for a buffer. Finds the proper unit, place it on
713 * the sortq and kick the controller.
716 xbd_strategy(struct bio *bp)
718 struct xbd_softc *sc = bp->bio_disk->d_drv1;
722 bp->bio_error = EINVAL;
723 bp->bio_flags |= BIO_ERROR;
724 bp->bio_resid = bp->bio_bcount;
730 * Place it in the queue of disk activities for this disk
732 mtx_lock(&sc->xbd_io_lock);
734 xbd_enqueue_bio(sc, bp);
737 mtx_unlock(&sc->xbd_io_lock);
741 /*------------------------------ Ring Management -----------------------------*/
743 xbd_alloc_ring(struct xbd_softc *sc)
745 blkif_sring_t *sring;
746 uintptr_t sring_page_addr;
750 sring = malloc(sc->xbd_ring_pages * PAGE_SIZE, M_XENBLOCKFRONT,
753 xenbus_dev_fatal(sc->xbd_dev, ENOMEM, "allocating shared ring");
756 SHARED_RING_INIT(sring);
757 FRONT_RING_INIT(&sc->xbd_ring, sring, sc->xbd_ring_pages * PAGE_SIZE);
759 for (i = 0, sring_page_addr = (uintptr_t)sring;
760 i < sc->xbd_ring_pages;
761 i++, sring_page_addr += PAGE_SIZE) {
763 error = xenbus_grant_ring(sc->xbd_dev,
764 (vtophys(sring_page_addr) >> PAGE_SHIFT),
765 &sc->xbd_ring_ref[i]);
767 xenbus_dev_fatal(sc->xbd_dev, error,
768 "granting ring_ref(%d)", i);
772 if (sc->xbd_ring_pages == 1) {
773 error = xs_printf(XST_NIL, xenbus_get_node(sc->xbd_dev),
774 "ring-ref", "%u", sc->xbd_ring_ref[0]);
776 xenbus_dev_fatal(sc->xbd_dev, error,
777 "writing %s/ring-ref",
778 xenbus_get_node(sc->xbd_dev));
782 for (i = 0; i < sc->xbd_ring_pages; i++) {
783 char ring_ref_name[]= "ring_refXX";
785 snprintf(ring_ref_name, sizeof(ring_ref_name),
787 error = xs_printf(XST_NIL, xenbus_get_node(sc->xbd_dev),
788 ring_ref_name, "%u", sc->xbd_ring_ref[i]);
790 xenbus_dev_fatal(sc->xbd_dev, error,
792 xenbus_get_node(sc->xbd_dev),
799 error = xen_intr_alloc_and_bind_local_port(sc->xbd_dev,
800 xenbus_get_otherend_id(sc->xbd_dev), NULL, xbd_int, sc,
801 INTR_TYPE_BIO | INTR_MPSAFE, &sc->xen_intr_handle);
803 xenbus_dev_fatal(sc->xbd_dev, error,
804 "xen_intr_alloc_and_bind_local_port failed");
812 xbd_free_ring(struct xbd_softc *sc)
816 if (sc->xbd_ring.sring == NULL)
819 for (i = 0; i < sc->xbd_ring_pages; i++) {
820 if (sc->xbd_ring_ref[i] != GRANT_REF_INVALID) {
821 gnttab_end_foreign_access_ref(sc->xbd_ring_ref[i]);
822 sc->xbd_ring_ref[i] = GRANT_REF_INVALID;
825 free(sc->xbd_ring.sring, M_XENBLOCKFRONT);
826 sc->xbd_ring.sring = NULL;
829 /*-------------------------- Initialization/Teardown -------------------------*/
831 xbd_feature_string(struct xbd_softc *sc, char *features, size_t len)
836 sbuf_new(&sb, features, len, SBUF_FIXEDLEN);
839 if ((sc->xbd_flags & XBDF_FLUSH) != 0) {
840 sbuf_printf(&sb, "flush");
844 if ((sc->xbd_flags & XBDF_BARRIER) != 0) {
845 if (feature_cnt != 0)
846 sbuf_printf(&sb, ", ");
847 sbuf_printf(&sb, "write_barrier");
851 (void) sbuf_finish(&sb);
852 return (sbuf_len(&sb));
856 xbd_sysctl_features(SYSCTL_HANDLER_ARGS)
859 struct xbd_softc *sc = arg1;
863 error = sysctl_wire_old_buffer(req, 0);
867 len = xbd_feature_string(sc, features, sizeof(features));
869 /* len is -1 on error, which will make the SYSCTL_OUT a no-op. */
870 return (SYSCTL_OUT(req, features, len + 1/*NUL*/));
874 xbd_setup_sysctl(struct xbd_softc *xbd)
876 struct sysctl_ctx_list *sysctl_ctx = NULL;
877 struct sysctl_oid *sysctl_tree = NULL;
878 struct sysctl_oid_list *children;
880 sysctl_ctx = device_get_sysctl_ctx(xbd->xbd_dev);
881 if (sysctl_ctx == NULL)
884 sysctl_tree = device_get_sysctl_tree(xbd->xbd_dev);
885 if (sysctl_tree == NULL)
888 children = SYSCTL_CHILDREN(sysctl_tree);
889 SYSCTL_ADD_UINT(sysctl_ctx, children, OID_AUTO,
890 "max_requests", CTLFLAG_RD, &xbd->xbd_max_requests, -1,
891 "maximum outstanding requests (negotiated)");
893 SYSCTL_ADD_UINT(sysctl_ctx, children, OID_AUTO,
894 "max_request_segments", CTLFLAG_RD,
895 &xbd->xbd_max_request_segments, 0,
896 "maximum number of pages per requests (negotiated)");
898 SYSCTL_ADD_UINT(sysctl_ctx, children, OID_AUTO,
899 "max_request_size", CTLFLAG_RD, &xbd->xbd_max_request_size, 0,
900 "maximum size in bytes of a request (negotiated)");
902 SYSCTL_ADD_UINT(sysctl_ctx, children, OID_AUTO,
903 "ring_pages", CTLFLAG_RD, &xbd->xbd_ring_pages, 0,
904 "communication channel pages (negotiated)");
906 SYSCTL_ADD_PROC(sysctl_ctx, children, OID_AUTO,
907 "features", CTLTYPE_STRING|CTLFLAG_RD, xbd, 0,
908 xbd_sysctl_features, "A", "protocol features (negotiated)");
912 * Translate Linux major/minor to an appropriate name and unit
913 * number. For HVM guests, this allows us to use the same drive names
914 * with blkfront as the emulated drives, easing transition slightly.
917 xbd_vdevice_to_unit(uint32_t vdevice, int *unit, const char **name)
919 static struct vdev_info {
925 {3, 6, 0, "ada"}, /* ide0 */
926 {22, 6, 2, "ada"}, /* ide1 */
927 {33, 6, 4, "ada"}, /* ide2 */
928 {34, 6, 6, "ada"}, /* ide3 */
929 {56, 6, 8, "ada"}, /* ide4 */
930 {57, 6, 10, "ada"}, /* ide5 */
931 {88, 6, 12, "ada"}, /* ide6 */
932 {89, 6, 14, "ada"}, /* ide7 */
933 {90, 6, 16, "ada"}, /* ide8 */
934 {91, 6, 18, "ada"}, /* ide9 */
936 {8, 4, 0, "da"}, /* scsi disk0 */
937 {65, 4, 16, "da"}, /* scsi disk1 */
938 {66, 4, 32, "da"}, /* scsi disk2 */
939 {67, 4, 48, "da"}, /* scsi disk3 */
940 {68, 4, 64, "da"}, /* scsi disk4 */
941 {69, 4, 80, "da"}, /* scsi disk5 */
942 {70, 4, 96, "da"}, /* scsi disk6 */
943 {71, 4, 112, "da"}, /* scsi disk7 */
944 {128, 4, 128, "da"}, /* scsi disk8 */
945 {129, 4, 144, "da"}, /* scsi disk9 */
946 {130, 4, 160, "da"}, /* scsi disk10 */
947 {131, 4, 176, "da"}, /* scsi disk11 */
948 {132, 4, 192, "da"}, /* scsi disk12 */
949 {133, 4, 208, "da"}, /* scsi disk13 */
950 {134, 4, 224, "da"}, /* scsi disk14 */
951 {135, 4, 240, "da"}, /* scsi disk15 */
953 {202, 4, 0, "xbd"}, /* xbd */
957 int major = vdevice >> 8;
958 int minor = vdevice & 0xff;
961 if (vdevice & (1 << 28)) {
962 *unit = (vdevice & ((1 << 28) - 1)) >> 8;
967 for (i = 0; info[i].major; i++) {
968 if (info[i].major == major) {
969 *unit = info[i].base + (minor >> info[i].shift);
970 *name = info[i].name;
980 xbd_instance_create(struct xbd_softc *sc, blkif_sector_t sectors,
981 int vdevice, uint16_t vdisk_info, unsigned long sector_size)
987 xbd_vdevice_to_unit(vdevice, &unit, &name);
991 if (strcmp(name, "xbd") != 0)
992 device_printf(sc->xbd_dev, "attaching as %s%d\n", name, unit);
994 if (xbd_feature_string(sc, features, sizeof(features)) > 0) {
995 device_printf(sc->xbd_dev, "features: %s\n",
999 sc->xbd_disk = disk_alloc();
1000 sc->xbd_disk->d_unit = sc->xbd_unit;
1001 sc->xbd_disk->d_open = xbd_open;
1002 sc->xbd_disk->d_close = xbd_close;
1003 sc->xbd_disk->d_ioctl = xbd_ioctl;
1004 sc->xbd_disk->d_strategy = xbd_strategy;
1005 sc->xbd_disk->d_dump = xbd_dump;
1006 sc->xbd_disk->d_name = name;
1007 sc->xbd_disk->d_drv1 = sc;
1008 sc->xbd_disk->d_sectorsize = sector_size;
1010 sc->xbd_disk->d_mediasize = sectors * sector_size;
1011 sc->xbd_disk->d_maxsize = sc->xbd_max_request_size;
1012 sc->xbd_disk->d_flags = 0;
1013 if ((sc->xbd_flags & (XBDF_FLUSH|XBDF_BARRIER)) != 0) {
1014 sc->xbd_disk->d_flags |= DISKFLAG_CANFLUSHCACHE;
1015 device_printf(sc->xbd_dev,
1016 "synchronize cache commands enabled.\n");
1018 disk_create(sc->xbd_disk, DISK_VERSION);
1024 xbd_free(struct xbd_softc *sc)
1028 /* Prevent new requests being issued until we fix things up. */
1029 mtx_lock(&sc->xbd_io_lock);
1030 sc->xbd_state = XBD_STATE_DISCONNECTED;
1031 mtx_unlock(&sc->xbd_io_lock);
1033 /* Free resources associated with old device channel. */
1035 if (sc->xbd_shadow) {
1037 for (i = 0; i < sc->xbd_max_requests; i++) {
1038 struct xbd_command *cm;
1040 cm = &sc->xbd_shadow[i];
1041 if (cm->cm_sg_refs != NULL) {
1042 free(cm->cm_sg_refs, M_XENBLOCKFRONT);
1043 cm->cm_sg_refs = NULL;
1046 if (cm->cm_indirectionpages != NULL) {
1047 gnttab_end_foreign_access_references(
1048 sc->xbd_max_request_indirectpages,
1049 &cm->cm_indirectionrefs[0]);
1050 contigfree(cm->cm_indirectionpages, PAGE_SIZE *
1051 sc->xbd_max_request_indirectpages,
1053 cm->cm_indirectionpages = NULL;
1056 bus_dmamap_destroy(sc->xbd_io_dmat, cm->cm_map);
1058 free(sc->xbd_shadow, M_XENBLOCKFRONT);
1059 sc->xbd_shadow = NULL;
1061 bus_dma_tag_destroy(sc->xbd_io_dmat);
1063 xbd_initq_cm(sc, XBD_Q_FREE);
1064 xbd_initq_cm(sc, XBD_Q_READY);
1065 xbd_initq_cm(sc, XBD_Q_COMPLETE);
1068 xen_intr_unbind(&sc->xen_intr_handle);
1072 /*--------------------------- State Change Handlers --------------------------*/
1074 xbd_initialize(struct xbd_softc *sc)
1076 const char *otherend_path;
1077 const char *node_path;
1078 uint32_t max_ring_page_order;
1081 if (xenbus_get_state(sc->xbd_dev) != XenbusStateInitialising) {
1082 /* Initialization has already been performed. */
1087 * Protocol defaults valid even if negotiation for a
1090 max_ring_page_order = 0;
1091 sc->xbd_ring_pages = 1;
1094 * Protocol negotiation.
1096 * \note xs_gather() returns on the first encountered error, so
1097 * we must use independant calls in order to guarantee
1098 * we don't miss information in a sparsly populated back-end
1101 * \note xs_scanf() does not update variables for unmatched
1104 otherend_path = xenbus_get_otherend_path(sc->xbd_dev);
1105 node_path = xenbus_get_node(sc->xbd_dev);
1107 /* Support both backend schemes for relaying ring page limits. */
1108 (void)xs_scanf(XST_NIL, otherend_path,
1109 "max-ring-page-order", NULL, "%" PRIu32,
1110 &max_ring_page_order);
1111 sc->xbd_ring_pages = 1 << max_ring_page_order;
1112 (void)xs_scanf(XST_NIL, otherend_path,
1113 "max-ring-pages", NULL, "%" PRIu32,
1114 &sc->xbd_ring_pages);
1115 if (sc->xbd_ring_pages < 1)
1116 sc->xbd_ring_pages = 1;
1118 if (sc->xbd_ring_pages > XBD_MAX_RING_PAGES) {
1119 device_printf(sc->xbd_dev,
1120 "Back-end specified ring-pages of %u "
1121 "limited to front-end limit of %u.\n",
1122 sc->xbd_ring_pages, XBD_MAX_RING_PAGES);
1123 sc->xbd_ring_pages = XBD_MAX_RING_PAGES;
1126 if (powerof2(sc->xbd_ring_pages) == 0) {
1127 uint32_t new_page_limit;
1129 new_page_limit = 0x01 << (fls(sc->xbd_ring_pages) - 1);
1130 device_printf(sc->xbd_dev,
1131 "Back-end specified ring-pages of %u "
1132 "is not a power of 2. Limited to %u.\n",
1133 sc->xbd_ring_pages, new_page_limit);
1134 sc->xbd_ring_pages = new_page_limit;
1137 sc->xbd_max_requests =
1138 BLKIF_MAX_RING_REQUESTS(sc->xbd_ring_pages * PAGE_SIZE);
1139 if (sc->xbd_max_requests > XBD_MAX_REQUESTS) {
1140 device_printf(sc->xbd_dev,
1141 "Back-end specified max_requests of %u "
1142 "limited to front-end limit of %zu.\n",
1143 sc->xbd_max_requests, XBD_MAX_REQUESTS);
1144 sc->xbd_max_requests = XBD_MAX_REQUESTS;
1147 if (xbd_alloc_ring(sc) != 0)
1150 /* Support both backend schemes for relaying ring page limits. */
1151 if (sc->xbd_ring_pages > 1) {
1152 error = xs_printf(XST_NIL, node_path,
1153 "num-ring-pages","%u",
1154 sc->xbd_ring_pages);
1156 xenbus_dev_fatal(sc->xbd_dev, error,
1157 "writing %s/num-ring-pages",
1162 error = xs_printf(XST_NIL, node_path,
1163 "ring-page-order", "%u",
1164 fls(sc->xbd_ring_pages) - 1);
1166 xenbus_dev_fatal(sc->xbd_dev, error,
1167 "writing %s/ring-page-order",
1173 error = xs_printf(XST_NIL, node_path, "event-channel",
1174 "%u", xen_intr_port(sc->xen_intr_handle));
1176 xenbus_dev_fatal(sc->xbd_dev, error,
1177 "writing %s/event-channel",
1182 error = xs_printf(XST_NIL, node_path, "protocol",
1183 "%s", XEN_IO_PROTO_ABI_NATIVE);
1185 xenbus_dev_fatal(sc->xbd_dev, error,
1186 "writing %s/protocol",
1191 xenbus_set_state(sc->xbd_dev, XenbusStateInitialised);
1195 * Invoked when the backend is finally 'ready' (and has published
1196 * the details about the physical device - #sectors, size, etc).
1199 xbd_connect(struct xbd_softc *sc)
1201 device_t dev = sc->xbd_dev;
1202 unsigned long sectors, sector_size;
1204 int err, feature_barrier, feature_flush;
1207 if (sc->xbd_state == XBD_STATE_CONNECTED ||
1208 sc->xbd_state == XBD_STATE_SUSPENDED)
1211 DPRINTK("blkfront.c:connect:%s.\n", xenbus_get_otherend_path(dev));
1213 err = xs_gather(XST_NIL, xenbus_get_otherend_path(dev),
1214 "sectors", "%lu", §ors,
1215 "info", "%u", &binfo,
1216 "sector-size", "%lu", §or_size,
1219 xenbus_dev_fatal(dev, err,
1220 "reading backend fields at %s",
1221 xenbus_get_otherend_path(dev));
1224 err = xs_gather(XST_NIL, xenbus_get_otherend_path(dev),
1225 "feature-barrier", "%lu", &feature_barrier,
1227 if (err == 0 && feature_barrier != 0)
1228 sc->xbd_flags |= XBDF_BARRIER;
1230 err = xs_gather(XST_NIL, xenbus_get_otherend_path(dev),
1231 "feature-flush-cache", "%lu", &feature_flush,
1233 if (err == 0 && feature_flush != 0)
1234 sc->xbd_flags |= XBDF_FLUSH;
1236 err = xs_gather(XST_NIL, xenbus_get_otherend_path(dev),
1237 "feature-max-indirect-segments", "%" PRIu32,
1238 &sc->xbd_max_request_segments, NULL);
1239 if ((err != 0) || (xbd_enable_indirect == 0))
1240 sc->xbd_max_request_segments = 0;
1241 if (sc->xbd_max_request_segments > XBD_MAX_INDIRECT_SEGMENTS)
1242 sc->xbd_max_request_segments = XBD_MAX_INDIRECT_SEGMENTS;
1243 if (sc->xbd_max_request_segments > XBD_SIZE_TO_SEGS(MAXPHYS))
1244 sc->xbd_max_request_segments = XBD_SIZE_TO_SEGS(MAXPHYS);
1245 sc->xbd_max_request_indirectpages =
1246 XBD_INDIRECT_SEGS_TO_PAGES(sc->xbd_max_request_segments);
1247 if (sc->xbd_max_request_segments < BLKIF_MAX_SEGMENTS_PER_REQUEST)
1248 sc->xbd_max_request_segments = BLKIF_MAX_SEGMENTS_PER_REQUEST;
1249 sc->xbd_max_request_size =
1250 XBD_SEGS_TO_SIZE(sc->xbd_max_request_segments);
1252 /* Allocate datastructures based on negotiated values. */
1253 err = bus_dma_tag_create(
1254 bus_get_dma_tag(sc->xbd_dev), /* parent */
1255 512, PAGE_SIZE, /* algnmnt, boundary */
1256 BUS_SPACE_MAXADDR, /* lowaddr */
1257 BUS_SPACE_MAXADDR, /* highaddr */
1258 NULL, NULL, /* filter, filterarg */
1259 sc->xbd_max_request_size,
1260 sc->xbd_max_request_segments,
1261 PAGE_SIZE, /* maxsegsize */
1262 BUS_DMA_ALLOCNOW, /* flags */
1263 busdma_lock_mutex, /* lockfunc */
1264 &sc->xbd_io_lock, /* lockarg */
1267 xenbus_dev_fatal(sc->xbd_dev, err,
1268 "Cannot allocate parent DMA tag\n");
1272 /* Per-transaction data allocation. */
1273 sc->xbd_shadow = malloc(sizeof(*sc->xbd_shadow) * sc->xbd_max_requests,
1274 M_XENBLOCKFRONT, M_NOWAIT|M_ZERO);
1275 if (sc->xbd_shadow == NULL) {
1276 bus_dma_tag_destroy(sc->xbd_io_dmat);
1277 xenbus_dev_fatal(sc->xbd_dev, ENOMEM,
1278 "Cannot allocate request structures\n");
1282 for (i = 0; i < sc->xbd_max_requests; i++) {
1283 struct xbd_command *cm;
1284 void * indirectpages;
1286 cm = &sc->xbd_shadow[i];
1287 cm->cm_sg_refs = malloc(
1288 sizeof(grant_ref_t) * sc->xbd_max_request_segments,
1289 M_XENBLOCKFRONT, M_NOWAIT);
1290 if (cm->cm_sg_refs == NULL)
1293 cm->cm_flags = XBDCF_INITIALIZER;
1295 if (bus_dmamap_create(sc->xbd_io_dmat, 0, &cm->cm_map) != 0)
1297 if (sc->xbd_max_request_indirectpages > 0) {
1298 indirectpages = contigmalloc(
1299 PAGE_SIZE * sc->xbd_max_request_indirectpages,
1300 M_XENBLOCKFRONT, M_ZERO, 0, ~0, PAGE_SIZE, 0);
1302 indirectpages = NULL;
1304 for (j = 0; j < sc->xbd_max_request_indirectpages; j++) {
1305 if (gnttab_grant_foreign_access(
1306 xenbus_get_otherend_id(sc->xbd_dev),
1307 (vtophys(indirectpages) >> PAGE_SHIFT) + j,
1308 1 /* grant read-only access */,
1309 &cm->cm_indirectionrefs[j]))
1312 if (j < sc->xbd_max_request_indirectpages)
1314 cm->cm_indirectionpages = indirectpages;
1315 xbd_free_command(cm);
1318 if (sc->xbd_disk == NULL) {
1319 device_printf(dev, "%juMB <%s> at %s",
1320 (uintmax_t) sectors / (1048576 / sector_size),
1321 device_get_desc(dev),
1322 xenbus_get_node(dev));
1323 bus_print_child_footer(device_get_parent(dev), dev);
1325 xbd_instance_create(sc, sectors, sc->xbd_vdevice, binfo,
1329 (void)xenbus_set_state(dev, XenbusStateConnected);
1331 /* Kick pending requests. */
1332 mtx_lock(&sc->xbd_io_lock);
1333 sc->xbd_state = XBD_STATE_CONNECTED;
1335 sc->xbd_flags |= XBDF_READY;
1336 mtx_unlock(&sc->xbd_io_lock);
1340 * Handle the change of state of the backend to Closing. We must delete our
1341 * device-layer structures now, to ensure that writes are flushed through to
1342 * the backend. Once this is done, we can switch to Closed in
1346 xbd_closing(device_t dev)
1348 struct xbd_softc *sc = device_get_softc(dev);
1350 xenbus_set_state(dev, XenbusStateClosing);
1352 DPRINTK("xbd_closing: %s removed\n", xenbus_get_node(dev));
1354 if (sc->xbd_disk != NULL) {
1355 disk_destroy(sc->xbd_disk);
1356 sc->xbd_disk = NULL;
1359 xenbus_set_state(dev, XenbusStateClosed);
1362 /*---------------------------- NewBus Entrypoints ----------------------------*/
1364 xbd_probe(device_t dev)
1366 if (strcmp(xenbus_get_type(dev), "vbd") != 0)
1369 if (xen_hvm_domain() && xen_disable_pv_disks != 0)
1372 if (xen_hvm_domain()) {
1377 * When running in an HVM domain, IDE disk emulation is
1378 * disabled early in boot so that native drivers will
1379 * not see emulated hardware. However, CDROM device
1380 * emulation cannot be disabled.
1382 * Through use of FreeBSD's vm_guest and xen_hvm_domain()
1383 * APIs, we could modify the native CDROM driver to fail its
1384 * probe when running under Xen. Unfortunatlely, the PV
1385 * CDROM support in XenServer (up through at least version
1386 * 6.2) isn't functional, so we instead rely on the emulated
1387 * CDROM instance, and fail to attach the PV one here in
1388 * the blkfront driver.
1390 error = xs_read(XST_NIL, xenbus_get_node(dev),
1391 "device-type", NULL, (void **) &type);
1395 if (strncmp(type, "cdrom", 5) == 0) {
1396 free(type, M_XENSTORE);
1399 free(type, M_XENSTORE);
1402 device_set_desc(dev, "Virtual Block Device");
1408 * Setup supplies the backend dir, virtual device. We place an event
1409 * channel and shared frame entries. We watch backend to wait if it's
1413 xbd_attach(device_t dev)
1415 struct xbd_softc *sc;
1422 /* FIXME: Use dynamic device id if this is not set. */
1423 error = xs_scanf(XST_NIL, xenbus_get_node(dev),
1424 "virtual-device", NULL, "%" PRIu32, &vdevice);
1426 error = xs_scanf(XST_NIL, xenbus_get_node(dev),
1427 "virtual-device-ext", NULL, "%" PRIu32, &vdevice);
1429 xenbus_dev_fatal(dev, error, "reading virtual-device");
1430 device_printf(dev, "Couldn't determine virtual device.\n");
1434 xbd_vdevice_to_unit(vdevice, &unit, &name);
1435 if (!strcmp(name, "xbd"))
1436 device_set_unit(dev, unit);
1438 sc = device_get_softc(dev);
1439 mtx_init(&sc->xbd_io_lock, "blkfront i/o lock", NULL, MTX_DEF);
1441 for (i = 0; i < XBD_MAX_RING_PAGES; i++)
1442 sc->xbd_ring_ref[i] = GRANT_REF_INVALID;
1445 sc->xbd_vdevice = vdevice;
1446 sc->xbd_state = XBD_STATE_DISCONNECTED;
1448 xbd_setup_sysctl(sc);
1450 /* Wait for backend device to publish its protocol capabilities. */
1451 xenbus_set_state(dev, XenbusStateInitialising);
1457 xbd_detach(device_t dev)
1459 struct xbd_softc *sc = device_get_softc(dev);
1461 DPRINTK("%s: %s removed\n", __func__, xenbus_get_node(dev));
1464 mtx_destroy(&sc->xbd_io_lock);
1470 xbd_suspend(device_t dev)
1472 struct xbd_softc *sc = device_get_softc(dev);
1476 /* Prevent new requests being issued until we fix things up. */
1477 mtx_lock(&sc->xbd_io_lock);
1478 saved_state = sc->xbd_state;
1479 sc->xbd_state = XBD_STATE_SUSPENDED;
1481 /* Wait for outstanding I/O to drain. */
1483 while (xbd_queue_length(sc, XBD_Q_BUSY) != 0) {
1484 if (msleep(&sc->xbd_cm_q[XBD_Q_BUSY], &sc->xbd_io_lock,
1485 PRIBIO, "blkf_susp", 30 * hz) == EWOULDBLOCK) {
1490 mtx_unlock(&sc->xbd_io_lock);
1493 sc->xbd_state = saved_state;
1499 xbd_resume(device_t dev)
1501 struct xbd_softc *sc = device_get_softc(dev);
1503 DPRINTK("xbd_resume: %s\n", xenbus_get_node(dev));
1511 * Callback received when the backend's state changes.
1514 xbd_backend_changed(device_t dev, XenbusState backend_state)
1516 struct xbd_softc *sc = device_get_softc(dev);
1518 DPRINTK("backend_state=%d\n", backend_state);
1520 switch (backend_state) {
1521 case XenbusStateUnknown:
1522 case XenbusStateInitialising:
1523 case XenbusStateReconfigured:
1524 case XenbusStateReconfiguring:
1525 case XenbusStateClosed:
1528 case XenbusStateInitWait:
1529 case XenbusStateInitialised:
1533 case XenbusStateConnected:
1538 case XenbusStateClosing:
1539 if (sc->xbd_users > 0)
1540 xenbus_dev_error(dev, -EBUSY,
1541 "Device in use; refusing to close");
1548 /*---------------------------- NewBus Registration ---------------------------*/
1549 static device_method_t xbd_methods[] = {
1550 /* Device interface */
1551 DEVMETHOD(device_probe, xbd_probe),
1552 DEVMETHOD(device_attach, xbd_attach),
1553 DEVMETHOD(device_detach, xbd_detach),
1554 DEVMETHOD(device_shutdown, bus_generic_shutdown),
1555 DEVMETHOD(device_suspend, xbd_suspend),
1556 DEVMETHOD(device_resume, xbd_resume),
1558 /* Xenbus interface */
1559 DEVMETHOD(xenbus_otherend_changed, xbd_backend_changed),
1564 static driver_t xbd_driver = {
1567 sizeof(struct xbd_softc),
1569 devclass_t xbd_devclass;
1571 DRIVER_MODULE(xbd, xenbusb_front, xbd_driver, xbd_devclass, 0, 0);