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/*
* XenBSD block device driver
*
* Copyright (c) 2009 Scott Long, Yahoo!
* Copyright (c) 2009 Frank Suchomel, Citrix
* Copyright (c) 2009 Doug F. Rabson, Citrix
* Copyright (c) 2005 Kip Macy
* Copyright (c) 2003-2004, Keir Fraser & Steve Hand
* Modifications by Mark A. Williamson are (c) Intel Research Cambridge
*
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to
* deal in the Software without restriction, including without limitation the
* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
* sell copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD: release/9.1.0/sys/dev/xen/blkfront/blkfront.c 237873 2012-07-01 05:13:50Z ken $");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/malloc.h>
#include <sys/kernel.h>
#include <vm/vm.h>
#include <vm/pmap.h>
#include <sys/bio.h>
#include <sys/bus.h>
#include <sys/conf.h>
#include <sys/module.h>
#include <sys/sysctl.h>
#include <machine/bus.h>
#include <sys/rman.h>
#include <machine/resource.h>
#include <machine/intr_machdep.h>
#include <machine/vmparam.h>
#include <sys/bus_dma.h>
#include <machine/_inttypes.h>
#include <machine/xen/xen-os.h>
#include <machine/xen/xenvar.h>
#include <machine/xen/xenfunc.h>
#include <xen/hypervisor.h>
#include <xen/xen_intr.h>
#include <xen/evtchn.h>
#include <xen/gnttab.h>
#include <xen/interface/grant_table.h>
#include <xen/interface/io/protocols.h>
#include <xen/xenbus/xenbusvar.h>
#include <geom/geom_disk.h>
#include <dev/xen/blkfront/block.h>
#include "xenbus_if.h"
/* prototypes */
static void xb_free_command(struct xb_command *cm);
static void xb_startio(struct xb_softc *sc);
static void blkfront_connect(struct xb_softc *);
static void blkfront_closing(device_t);
static int blkfront_detach(device_t);
static int setup_blkring(struct xb_softc *);
static void blkif_int(void *);
static void blkfront_initialize(struct xb_softc *);
static int blkif_completion(struct xb_command *);
static void blkif_free(struct xb_softc *);
static void blkif_queue_cb(void *, bus_dma_segment_t *, int, int);
MALLOC_DEFINE(M_XENBLOCKFRONT, "xbd", "Xen Block Front driver data");
#define GRANT_INVALID_REF 0
/* Control whether runtime update of vbds is enabled. */
#define ENABLE_VBD_UPDATE 0
#if ENABLE_VBD_UPDATE
static void vbd_update(void);
#endif
#define BLKIF_STATE_DISCONNECTED 0
#define BLKIF_STATE_CONNECTED 1
#define BLKIF_STATE_SUSPENDED 2
#ifdef notyet
static char *blkif_state_name[] = {
[BLKIF_STATE_DISCONNECTED] = "disconnected",
[BLKIF_STATE_CONNECTED] = "connected",
[BLKIF_STATE_SUSPENDED] = "closed",
};
static char * blkif_status_name[] = {
[BLKIF_INTERFACE_STATUS_CLOSED] = "closed",
[BLKIF_INTERFACE_STATUS_DISCONNECTED] = "disconnected",
[BLKIF_INTERFACE_STATUS_CONNECTED] = "connected",
[BLKIF_INTERFACE_STATUS_CHANGED] = "changed",
};
#endif
#if 0
#define DPRINTK(fmt, args...) printf("[XEN] %s:%d: " fmt ".\n", __func__, __LINE__, ##args)
#else
#define DPRINTK(fmt, args...)
#endif
static int blkif_open(struct disk *dp);
static int blkif_close(struct disk *dp);
static int blkif_ioctl(struct disk *dp, u_long cmd, void *addr, int flag, struct thread *td);
static int blkif_queue_request(struct xb_softc *sc, struct xb_command *cm);
static void xb_strategy(struct bio *bp);
// In order to quiesce the device during kernel dumps, outstanding requests to
// DOM0 for disk reads/writes need to be accounted for.
static int xb_dump(void *, void *, vm_offset_t, off_t, size_t);
/* XXX move to xb_vbd.c when VBD update support is added */
#define MAX_VBDS 64
#define XBD_SECTOR_SIZE 512 /* XXX: assume for now */
#define XBD_SECTOR_SHFT 9
/*
* Translate Linux major/minor to an appropriate name and unit
* number. For HVM guests, this allows us to use the same drive names
* with blkfront as the emulated drives, easing transition slightly.
*/
static void
blkfront_vdevice_to_unit(uint32_t vdevice, int *unit, const char **name)
{
static struct vdev_info {
int major;
int shift;
int base;
const char *name;
} info[] = {
{3, 6, 0, "ad"}, /* ide0 */
{22, 6, 2, "ad"}, /* ide1 */
{33, 6, 4, "ad"}, /* ide2 */
{34, 6, 6, "ad"}, /* ide3 */
{56, 6, 8, "ad"}, /* ide4 */
{57, 6, 10, "ad"}, /* ide5 */
{88, 6, 12, "ad"}, /* ide6 */
{89, 6, 14, "ad"}, /* ide7 */
{90, 6, 16, "ad"}, /* ide8 */
{91, 6, 18, "ad"}, /* ide9 */
{8, 4, 0, "da"}, /* scsi disk0 */
{65, 4, 16, "da"}, /* scsi disk1 */
{66, 4, 32, "da"}, /* scsi disk2 */
{67, 4, 48, "da"}, /* scsi disk3 */
{68, 4, 64, "da"}, /* scsi disk4 */
{69, 4, 80, "da"}, /* scsi disk5 */
{70, 4, 96, "da"}, /* scsi disk6 */
{71, 4, 112, "da"}, /* scsi disk7 */
{128, 4, 128, "da"}, /* scsi disk8 */
{129, 4, 144, "da"}, /* scsi disk9 */
{130, 4, 160, "da"}, /* scsi disk10 */
{131, 4, 176, "da"}, /* scsi disk11 */
{132, 4, 192, "da"}, /* scsi disk12 */
{133, 4, 208, "da"}, /* scsi disk13 */
{134, 4, 224, "da"}, /* scsi disk14 */
{135, 4, 240, "da"}, /* scsi disk15 */
{202, 4, 0, "xbd"}, /* xbd */
{0, 0, 0, NULL},
};
int major = vdevice >> 8;
int minor = vdevice & 0xff;
int i;
if (vdevice & (1 << 28)) {
*unit = (vdevice & ((1 << 28) - 1)) >> 8;
*name = "xbd";
return;
}
for (i = 0; info[i].major; i++) {
if (info[i].major == major) {
*unit = info[i].base + (minor >> info[i].shift);
*name = info[i].name;
return;
}
}
*unit = minor >> 4;
*name = "xbd";
}
int
xlvbd_add(struct xb_softc *sc, blkif_sector_t sectors,
int vdevice, uint16_t vdisk_info, unsigned long sector_size)
{
int unit, error = 0;
const char *name;
blkfront_vdevice_to_unit(vdevice, &unit, &name);
sc->xb_unit = unit;
if (strcmp(name, "xbd"))
device_printf(sc->xb_dev, "attaching as %s%d\n", name, unit);
sc->xb_disk = disk_alloc();
sc->xb_disk->d_unit = sc->xb_unit;
sc->xb_disk->d_open = blkif_open;
sc->xb_disk->d_close = blkif_close;
sc->xb_disk->d_ioctl = blkif_ioctl;
sc->xb_disk->d_strategy = xb_strategy;
sc->xb_disk->d_dump = xb_dump;
sc->xb_disk->d_name = name;
sc->xb_disk->d_drv1 = sc;
sc->xb_disk->d_sectorsize = sector_size;
sc->xb_disk->d_mediasize = sectors * sector_size;
sc->xb_disk->d_maxsize = sc->max_request_size;
sc->xb_disk->d_flags = 0;
disk_create(sc->xb_disk, DISK_VERSION);
return error;
}
/************************ end VBD support *****************/
/*
* Read/write routine for a buffer. Finds the proper unit, place it on
* the sortq and kick the controller.
*/
static void
xb_strategy(struct bio *bp)
{
struct xb_softc *sc = (struct xb_softc *)bp->bio_disk->d_drv1;
/* bogus disk? */
if (sc == NULL) {
bp->bio_error = EINVAL;
bp->bio_flags |= BIO_ERROR;
bp->bio_resid = bp->bio_bcount;
biodone(bp);
return;
}
/*
* Place it in the queue of disk activities for this disk
*/
mtx_lock(&sc->xb_io_lock);
xb_enqueue_bio(sc, bp);
xb_startio(sc);
mtx_unlock(&sc->xb_io_lock);
return;
}
static void
xb_bio_complete(struct xb_softc *sc, struct xb_command *cm)
{
struct bio *bp;
bp = cm->bp;
if ( unlikely(cm->status != BLKIF_RSP_OKAY) ) {
disk_err(bp, "disk error" , -1, 0);
printf(" status: %x\n", cm->status);
bp->bio_flags |= BIO_ERROR;
}
if (bp->bio_flags & BIO_ERROR)
bp->bio_error = EIO;
else
bp->bio_resid = 0;
xb_free_command(cm);
biodone(bp);
}
// Quiesce the disk writes for a dump file before allowing the next buffer.
static void
xb_quiesce(struct xb_softc *sc)
{
int mtd;
// While there are outstanding requests
while (!TAILQ_EMPTY(&sc->cm_busy)) {
RING_FINAL_CHECK_FOR_RESPONSES(&sc->ring, mtd);
if (mtd) {
/* Recieved request completions, update queue. */
blkif_int(sc);
}
if (!TAILQ_EMPTY(&sc->cm_busy)) {
/*
* Still pending requests, wait for the disk i/o
* to complete.
*/
HYPERVISOR_yield();
}
}
}
/* Kernel dump function for a paravirtualized disk device */
static void
xb_dump_complete(struct xb_command *cm)
{
xb_enqueue_complete(cm);
}
static int
xb_dump(void *arg, void *virtual, vm_offset_t physical, off_t offset,
size_t length)
{
struct disk *dp = arg;
struct xb_softc *sc = (struct xb_softc *) dp->d_drv1;
struct xb_command *cm;
size_t chunk;
int sbp;
int rc = 0;
if (length <= 0)
return (rc);
xb_quiesce(sc); /* All quiet on the western front. */
/*
* If this lock is held, then this module is failing, and a
* successful kernel dump is highly unlikely anyway.
*/
mtx_lock(&sc->xb_io_lock);
/* Split the 64KB block as needed */
for (sbp=0; length > 0; sbp++) {
cm = xb_dequeue_free(sc);
if (cm == NULL) {
mtx_unlock(&sc->xb_io_lock);
device_printf(sc->xb_dev, "dump: no more commands?\n");
return (EBUSY);
}
if (gnttab_alloc_grant_references(sc->max_request_segments,
&cm->gref_head) != 0) {
xb_free_command(cm);
mtx_unlock(&sc->xb_io_lock);
device_printf(sc->xb_dev, "no more grant allocs?\n");
return (EBUSY);
}
chunk = length > sc->max_request_size
? sc->max_request_size : length;
cm->data = virtual;
cm->datalen = chunk;
cm->operation = BLKIF_OP_WRITE;
cm->sector_number = offset / dp->d_sectorsize;
cm->cm_complete = xb_dump_complete;
xb_enqueue_ready(cm);
length -= chunk;
offset += chunk;
virtual = (char *) virtual + chunk;
}
/* Tell DOM0 to do the I/O */
xb_startio(sc);
mtx_unlock(&sc->xb_io_lock);
/* Poll for the completion. */
xb_quiesce(sc); /* All quite on the eastern front */
/* If there were any errors, bail out... */
while ((cm = xb_dequeue_complete(sc)) != NULL) {
if (cm->status != BLKIF_RSP_OKAY) {
device_printf(sc->xb_dev,
"Dump I/O failed at sector %jd\n",
cm->sector_number);
rc = EIO;
}
xb_free_command(cm);
}
return (rc);
}
static int
blkfront_probe(device_t dev)
{
if (!strcmp(xenbus_get_type(dev), "vbd")) {
device_set_desc(dev, "Virtual Block Device");
device_quiet(dev);
return (0);
}
return (ENXIO);
}
static void
xb_setup_sysctl(struct xb_softc *xb)
{
struct sysctl_ctx_list *sysctl_ctx = NULL;
struct sysctl_oid *sysctl_tree = NULL;
sysctl_ctx = device_get_sysctl_ctx(xb->xb_dev);
if (sysctl_ctx == NULL)
return;
sysctl_tree = device_get_sysctl_tree(xb->xb_dev);
if (sysctl_tree == NULL)
return;
SYSCTL_ADD_UINT(sysctl_ctx, SYSCTL_CHILDREN(sysctl_tree), OID_AUTO,
"max_requests", CTLFLAG_RD, &xb->max_requests, -1,
"maximum outstanding requests (negotiated)");
SYSCTL_ADD_UINT(sysctl_ctx, SYSCTL_CHILDREN(sysctl_tree), OID_AUTO,
"max_request_segments", CTLFLAG_RD,
&xb->max_request_segments, 0,
"maximum number of pages per requests (negotiated)");
SYSCTL_ADD_UINT(sysctl_ctx, SYSCTL_CHILDREN(sysctl_tree), OID_AUTO,
"max_request_size", CTLFLAG_RD,
&xb->max_request_size, 0,
"maximum size in bytes of a request (negotiated)");
SYSCTL_ADD_UINT(sysctl_ctx, SYSCTL_CHILDREN(sysctl_tree), OID_AUTO,
"ring_pages", CTLFLAG_RD,
&xb->ring_pages, 0,
"communication channel pages (negotiated)");
}
/*
* Setup supplies the backend dir, virtual device. We place an event
* channel and shared frame entries. We watch backend to wait if it's
* ok.
*/
static int
blkfront_attach(device_t dev)
{
struct xb_softc *sc;
const char *name;
uint32_t vdevice;
int error;
int i;
int unit;
/* FIXME: Use dynamic device id if this is not set. */
error = xs_scanf(XST_NIL, xenbus_get_node(dev),
"virtual-device", NULL, "%" PRIu32, &vdevice);
if (error) {
xenbus_dev_fatal(dev, error, "reading virtual-device");
device_printf(dev, "Couldn't determine virtual device.\n");
return (error);
}
blkfront_vdevice_to_unit(vdevice, &unit, &name);
if (!strcmp(name, "xbd"))
device_set_unit(dev, unit);
sc = device_get_softc(dev);
mtx_init(&sc->xb_io_lock, "blkfront i/o lock", NULL, MTX_DEF);
xb_initq_free(sc);
xb_initq_busy(sc);
xb_initq_ready(sc);
xb_initq_complete(sc);
xb_initq_bio(sc);
for (i = 0; i < XBF_MAX_RING_PAGES; i++)
sc->ring_ref[i] = GRANT_INVALID_REF;
sc->xb_dev = dev;
sc->vdevice = vdevice;
sc->connected = BLKIF_STATE_DISCONNECTED;
xb_setup_sysctl(sc);
/* Wait for backend device to publish its protocol capabilities. */
xenbus_set_state(dev, XenbusStateInitialising);
return (0);
}
static int
blkfront_suspend(device_t dev)
{
struct xb_softc *sc = device_get_softc(dev);
int retval;
int saved_state;
/* Prevent new requests being issued until we fix things up. */
mtx_lock(&sc->xb_io_lock);
saved_state = sc->connected;
sc->connected = BLKIF_STATE_SUSPENDED;
/* Wait for outstanding I/O to drain. */
retval = 0;
while (TAILQ_EMPTY(&sc->cm_busy) == 0) {
if (msleep(&sc->cm_busy, &sc->xb_io_lock,
PRIBIO, "blkf_susp", 30 * hz) == EWOULDBLOCK) {
retval = EBUSY;
break;
}
}
mtx_unlock(&sc->xb_io_lock);
if (retval != 0)
sc->connected = saved_state;
return (retval);
}
static int
blkfront_resume(device_t dev)
{
struct xb_softc *sc = device_get_softc(dev);
DPRINTK("blkfront_resume: %s\n", xenbus_get_node(dev));
blkif_free(sc);
blkfront_initialize(sc);
return (0);
}
static void
blkfront_initialize(struct xb_softc *sc)
{
const char *otherend_path;
const char *node_path;
uint32_t max_ring_page_order;
int error;
int i;
if (xenbus_get_state(sc->xb_dev) != XenbusStateInitialising) {
/* Initialization has already been performed. */
return;
}
/*
* Protocol defaults valid even if negotiation for a
* setting fails.
*/
max_ring_page_order = 0;
sc->ring_pages = 1;
sc->max_request_segments = BLKIF_MAX_SEGMENTS_PER_HEADER_BLOCK;
sc->max_request_size = XBF_SEGS_TO_SIZE(sc->max_request_segments);
sc->max_request_blocks = BLKIF_SEGS_TO_BLOCKS(sc->max_request_segments);
/*
* Protocol negotiation.
*
* \note xs_gather() returns on the first encountered error, so
* we must use independant calls in order to guarantee
* we don't miss information in a sparsly populated back-end
* tree.
*
* \note xs_scanf() does not update variables for unmatched
* fields.
*/
otherend_path = xenbus_get_otherend_path(sc->xb_dev);
node_path = xenbus_get_node(sc->xb_dev);
/* Support both backend schemes for relaying ring page limits. */
(void)xs_scanf(XST_NIL, otherend_path,
"max-ring-page-order", NULL, "%" PRIu32,
&max_ring_page_order);
sc->ring_pages = 1 << max_ring_page_order;
(void)xs_scanf(XST_NIL, otherend_path,
"max-ring-pages", NULL, "%" PRIu32,
&sc->ring_pages);
if (sc->ring_pages < 1)
sc->ring_pages = 1;
sc->max_requests = BLKIF_MAX_RING_REQUESTS(sc->ring_pages * PAGE_SIZE);
(void)xs_scanf(XST_NIL, otherend_path,
"max-requests", NULL, "%" PRIu32,
&sc->max_requests);
(void)xs_scanf(XST_NIL, otherend_path,
"max-request-segments", NULL, "%" PRIu32,
&sc->max_request_segments);
(void)xs_scanf(XST_NIL, otherend_path,
"max-request-size", NULL, "%" PRIu32,
&sc->max_request_size);
if (sc->ring_pages > XBF_MAX_RING_PAGES) {
device_printf(sc->xb_dev, "Back-end specified ring-pages of "
"%u limited to front-end limit of %zu.\n",
sc->ring_pages, XBF_MAX_RING_PAGES);
sc->ring_pages = XBF_MAX_RING_PAGES;
}
if (powerof2(sc->ring_pages) == 0) {
uint32_t new_page_limit;
new_page_limit = 0x01 << (fls(sc->ring_pages) - 1);
device_printf(sc->xb_dev, "Back-end specified ring-pages of "
"%u is not a power of 2. Limited to %u.\n",
sc->ring_pages, new_page_limit);
sc->ring_pages = new_page_limit;
}
if (sc->max_requests > XBF_MAX_REQUESTS) {
device_printf(sc->xb_dev, "Back-end specified max_requests of "
"%u limited to front-end limit of %u.\n",
sc->max_requests, XBF_MAX_REQUESTS);
sc->max_requests = XBF_MAX_REQUESTS;
}
if (sc->max_request_segments > XBF_MAX_SEGMENTS_PER_REQUEST) {
device_printf(sc->xb_dev, "Back-end specified "
"max_request_segments of %u limited to "
"front-end limit of %u.\n",
sc->max_request_segments,
XBF_MAX_SEGMENTS_PER_REQUEST);
sc->max_request_segments = XBF_MAX_SEGMENTS_PER_REQUEST;
}
if (sc->max_request_size > XBF_MAX_REQUEST_SIZE) {
device_printf(sc->xb_dev, "Back-end specified "
"max_request_size of %u limited to front-end "
"limit of %u.\n", sc->max_request_size,
XBF_MAX_REQUEST_SIZE);
sc->max_request_size = XBF_MAX_REQUEST_SIZE;
}
if (sc->max_request_size > XBF_SEGS_TO_SIZE(sc->max_request_segments)) {
device_printf(sc->xb_dev, "Back-end specified "
"max_request_size of %u limited to front-end "
"limit of %u. (Too few segments.)\n",
sc->max_request_size,
XBF_SEGS_TO_SIZE(sc->max_request_segments));
sc->max_request_size =
XBF_SEGS_TO_SIZE(sc->max_request_segments);
}
sc->max_request_blocks = BLKIF_SEGS_TO_BLOCKS(sc->max_request_segments);
/* Allocate datastructures based on negotiated values. */
error = bus_dma_tag_create(bus_get_dma_tag(sc->xb_dev), /* parent */
512, PAGE_SIZE, /* algnmnt, boundary */
BUS_SPACE_MAXADDR, /* lowaddr */
BUS_SPACE_MAXADDR, /* highaddr */
NULL, NULL, /* filter, filterarg */
sc->max_request_size,
sc->max_request_segments,
PAGE_SIZE, /* maxsegsize */
BUS_DMA_ALLOCNOW, /* flags */
busdma_lock_mutex, /* lockfunc */
&sc->xb_io_lock, /* lockarg */
&sc->xb_io_dmat);
if (error != 0) {
xenbus_dev_fatal(sc->xb_dev, error,
"Cannot allocate parent DMA tag\n");
return;
}
/* Per-transaction data allocation. */
sc->shadow = malloc(sizeof(*sc->shadow) * sc->max_requests,
M_XENBLOCKFRONT, M_NOWAIT|M_ZERO);
if (sc->shadow == NULL) {
bus_dma_tag_destroy(sc->xb_io_dmat);
xenbus_dev_fatal(sc->xb_dev, error,
"Cannot allocate request structures\n");
return;
}
for (i = 0; i < sc->max_requests; i++) {
struct xb_command *cm;
cm = &sc->shadow[i];
cm->sg_refs = malloc(sizeof(grant_ref_t)
* sc->max_request_segments,
M_XENBLOCKFRONT, M_NOWAIT);
if (cm->sg_refs == NULL)
break;
cm->id = i;
cm->cm_sc = sc;
if (bus_dmamap_create(sc->xb_io_dmat, 0, &cm->map) != 0)
break;
xb_free_command(cm);
}
if (setup_blkring(sc) != 0)
return;
/* Support both backend schemes for relaying ring page limits. */
if (sc->ring_pages > 1) {
error = xs_printf(XST_NIL, node_path,
"num-ring-pages","%u", sc->ring_pages);
if (error) {
xenbus_dev_fatal(sc->xb_dev, error,
"writing %s/num-ring-pages",
node_path);
return;
}
error = xs_printf(XST_NIL, node_path,
"ring-page-order", "%u",
fls(sc->ring_pages) - 1);
if (error) {
xenbus_dev_fatal(sc->xb_dev, error,
"writing %s/ring-page-order",
node_path);
return;
}
}
error = xs_printf(XST_NIL, node_path,
"max-requests","%u", sc->max_requests);
if (error) {
xenbus_dev_fatal(sc->xb_dev, error,
"writing %s/max-requests",
node_path);
return;
}
error = xs_printf(XST_NIL, node_path,
"max-request-segments","%u", sc->max_request_segments);
if (error) {
xenbus_dev_fatal(sc->xb_dev, error,
"writing %s/max-request-segments",
node_path);
return;
}
error = xs_printf(XST_NIL, node_path,
"max-request-size","%u", sc->max_request_size);
if (error) {
xenbus_dev_fatal(sc->xb_dev, error,
"writing %s/max-request-size",
node_path);
return;
}
error = xs_printf(XST_NIL, node_path, "event-channel",
"%u", irq_to_evtchn_port(sc->irq));
if (error) {
xenbus_dev_fatal(sc->xb_dev, error,
"writing %s/event-channel",
node_path);
return;
}
error = xs_printf(XST_NIL, node_path,
"protocol", "%s", XEN_IO_PROTO_ABI_NATIVE);
if (error) {
xenbus_dev_fatal(sc->xb_dev, error,
"writing %s/protocol",
node_path);
return;
}
xenbus_set_state(sc->xb_dev, XenbusStateInitialised);
}
static int
setup_blkring(struct xb_softc *sc)
{
blkif_sring_t *sring;
uintptr_t sring_page_addr;
int error;
int i;
sring = malloc(sc->ring_pages * PAGE_SIZE, M_XENBLOCKFRONT,
M_NOWAIT|M_ZERO);
if (sring == NULL) {
xenbus_dev_fatal(sc->xb_dev, ENOMEM, "allocating shared ring");
return (ENOMEM);
}
SHARED_RING_INIT(sring);
FRONT_RING_INIT(&sc->ring, sring, sc->ring_pages * PAGE_SIZE);
for (i = 0, sring_page_addr = (uintptr_t)sring;
i < sc->ring_pages;
i++, sring_page_addr += PAGE_SIZE) {
error = xenbus_grant_ring(sc->xb_dev,
(vtomach(sring_page_addr) >> PAGE_SHIFT), &sc->ring_ref[i]);
if (error) {
xenbus_dev_fatal(sc->xb_dev, error,
"granting ring_ref(%d)", i);
return (error);
}
}
if (sc->ring_pages == 1) {
error = xs_printf(XST_NIL, xenbus_get_node(sc->xb_dev),
"ring-ref", "%u", sc->ring_ref[0]);
if (error) {
xenbus_dev_fatal(sc->xb_dev, error,
"writing %s/ring-ref",
xenbus_get_node(sc->xb_dev));
return (error);
}
} else {
for (i = 0; i < sc->ring_pages; i++) {
char ring_ref_name[]= "ring_refXX";
snprintf(ring_ref_name, sizeof(ring_ref_name),
"ring-ref%u", i);
error = xs_printf(XST_NIL, xenbus_get_node(sc->xb_dev),
ring_ref_name, "%u", sc->ring_ref[i]);
if (error) {
xenbus_dev_fatal(sc->xb_dev, error,
"writing %s/%s",
xenbus_get_node(sc->xb_dev),
ring_ref_name);
return (error);
}
}
}
error = bind_listening_port_to_irqhandler(
xenbus_get_otherend_id(sc->xb_dev),
"xbd", (driver_intr_t *)blkif_int, sc,
INTR_TYPE_BIO | INTR_MPSAFE, &sc->irq);
if (error) {
xenbus_dev_fatal(sc->xb_dev, error,
"bind_evtchn_to_irqhandler failed");
return (error);
}
return (0);
}
/**
* Callback received when the backend's state changes.
*/
static void
blkfront_backend_changed(device_t dev, XenbusState backend_state)
{
struct xb_softc *sc = device_get_softc(dev);
DPRINTK("backend_state=%d\n", backend_state);
switch (backend_state) {
case XenbusStateUnknown:
case XenbusStateInitialising:
case XenbusStateReconfigured:
case XenbusStateReconfiguring:
case XenbusStateClosed:
break;
case XenbusStateInitWait:
case XenbusStateInitialised:
blkfront_initialize(sc);
break;
case XenbusStateConnected:
blkfront_initialize(sc);
blkfront_connect(sc);
break;
case XenbusStateClosing:
if (sc->users > 0)
xenbus_dev_error(dev, -EBUSY,
"Device in use; refusing to close");
else
blkfront_closing(dev);
break;
}
}
/*
** Invoked when the backend is finally 'ready' (and has published
** the details about the physical device - #sectors, size, etc).
*/
static void
blkfront_connect(struct xb_softc *sc)
{
device_t dev = sc->xb_dev;
unsigned long sectors, sector_size;
unsigned int binfo;
int err, feature_barrier;
if( (sc->connected == BLKIF_STATE_CONNECTED) ||
(sc->connected == BLKIF_STATE_SUSPENDED) )
return;
DPRINTK("blkfront.c:connect:%s.\n", xenbus_get_otherend_path(dev));
err = xs_gather(XST_NIL, xenbus_get_otherend_path(dev),
"sectors", "%lu", §ors,
"info", "%u", &binfo,
"sector-size", "%lu", §or_size,
NULL);
if (err) {
xenbus_dev_fatal(dev, err,
"reading backend fields at %s",
xenbus_get_otherend_path(dev));
return;
}
err = xs_gather(XST_NIL, xenbus_get_otherend_path(dev),
"feature-barrier", "%lu", &feature_barrier,
NULL);
if (!err || feature_barrier)
sc->xb_flags |= XB_BARRIER;
if (sc->xb_disk == NULL) {
device_printf(dev, "%juMB <%s> at %s",
(uintmax_t) sectors / (1048576 / sector_size),
device_get_desc(dev),
xenbus_get_node(dev));
bus_print_child_footer(device_get_parent(dev), dev);
xlvbd_add(sc, sectors, sc->vdevice, binfo, sector_size);
}
(void)xenbus_set_state(dev, XenbusStateConnected);
/* Kick pending requests. */
mtx_lock(&sc->xb_io_lock);
sc->connected = BLKIF_STATE_CONNECTED;
xb_startio(sc);
sc->xb_flags |= XB_READY;
mtx_unlock(&sc->xb_io_lock);
}
/**
* Handle the change of state of the backend to Closing. We must delete our
* device-layer structures now, to ensure that writes are flushed through to
* the backend. Once this is done, we can switch to Closed in
* acknowledgement.
*/
static void
blkfront_closing(device_t dev)
{
struct xb_softc *sc = device_get_softc(dev);
xenbus_set_state(dev, XenbusStateClosing);
DPRINTK("blkfront_closing: %s removed\n", xenbus_get_node(dev));
if (sc->xb_disk != NULL) {
disk_destroy(sc->xb_disk);
sc->xb_disk = NULL;
}
xenbus_set_state(dev, XenbusStateClosed);
}
static int
blkfront_detach(device_t dev)
{
struct xb_softc *sc = device_get_softc(dev);
DPRINTK("blkfront_remove: %s removed\n", xenbus_get_node(dev));
blkif_free(sc);
mtx_destroy(&sc->xb_io_lock);
return 0;
}
static inline void
flush_requests(struct xb_softc *sc)
{
int notify;
RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&sc->ring, notify);
if (notify)
notify_remote_via_irq(sc->irq);
}
static void
blkif_restart_queue_callback(void *arg)
{
struct xb_softc *sc = arg;
mtx_lock(&sc->xb_io_lock);
xb_startio(sc);
mtx_unlock(&sc->xb_io_lock);
}
static int
blkif_open(struct disk *dp)
{
struct xb_softc *sc = (struct xb_softc *)dp->d_drv1;
if (sc == NULL) {
printf("xb%d: not found", sc->xb_unit);
return (ENXIO);
}
sc->xb_flags |= XB_OPEN;
sc->users++;
return (0);
}
static int
blkif_close(struct disk *dp)
{
struct xb_softc *sc = (struct xb_softc *)dp->d_drv1;
if (sc == NULL)
return (ENXIO);
sc->xb_flags &= ~XB_OPEN;
if (--(sc->users) == 0) {
/*
* Check whether we have been instructed to close. We will
* have ignored this request initially, as the device was
* still mounted.
*/
if (xenbus_get_otherend_state(sc->xb_dev) == XenbusStateClosing)
blkfront_closing(sc->xb_dev);
}
return (0);
}
static int
blkif_ioctl(struct disk *dp, u_long cmd, void *addr, int flag, struct thread *td)
{
struct xb_softc *sc = (struct xb_softc *)dp->d_drv1;
if (sc == NULL)
return (ENXIO);
return (ENOTTY);
}
static void
xb_free_command(struct xb_command *cm)
{
KASSERT((cm->cm_flags & XB_ON_XBQ_MASK) == 0,
("Freeing command that is still on a queue\n"));
cm->cm_flags = 0;
cm->bp = NULL;
cm->cm_complete = NULL;
xb_enqueue_free(cm);
}
/*
* blkif_queue_request
*
* request block io
*
* id: for guest use only.
* operation: BLKIF_OP_{READ,WRITE,PROBE}
* buffer: buffer to read/write into. this should be a
* virtual address in the guest os.
*/
static struct xb_command *
xb_bio_command(struct xb_softc *sc)
{
struct xb_command *cm;
struct bio *bp;
if (unlikely(sc->connected != BLKIF_STATE_CONNECTED))
return (NULL);
bp = xb_dequeue_bio(sc);
if (bp == NULL)
return (NULL);
if ((cm = xb_dequeue_free(sc)) == NULL) {
xb_requeue_bio(sc, bp);
return (NULL);
}
if (gnttab_alloc_grant_references(sc->max_request_segments,
&cm->gref_head) != 0) {
gnttab_request_free_callback(&sc->callback,
blkif_restart_queue_callback, sc,
sc->max_request_segments);
xb_requeue_bio(sc, bp);
xb_enqueue_free(cm);
sc->xb_flags |= XB_FROZEN;
return (NULL);
}
cm->bp = bp;
cm->data = bp->bio_data;
cm->datalen = bp->bio_bcount;
cm->operation = (bp->bio_cmd == BIO_READ) ? BLKIF_OP_READ :
BLKIF_OP_WRITE;
cm->sector_number = (blkif_sector_t)bp->bio_pblkno;
return (cm);
}
static int
blkif_queue_request(struct xb_softc *sc, struct xb_command *cm)
{
int error;
error = bus_dmamap_load(sc->xb_io_dmat, cm->map, cm->data, cm->datalen,
blkif_queue_cb, cm, 0);
if (error == EINPROGRESS) {
printf("EINPROGRESS\n");
sc->xb_flags |= XB_FROZEN;
cm->cm_flags |= XB_CMD_FROZEN;
return (0);
}
return (error);
}
static void
blkif_queue_cb(void *arg, bus_dma_segment_t *segs, int nsegs, int error)
{
struct xb_softc *sc;
struct xb_command *cm;
blkif_request_t *ring_req;
struct blkif_request_segment *sg;
struct blkif_request_segment *last_block_sg;
grant_ref_t *sg_ref;
vm_paddr_t buffer_ma;
uint64_t fsect, lsect;
int ref;
int op;
int block_segs;
cm = arg;
sc = cm->cm_sc;
//printf("%s: Start\n", __func__);
if (error) {
printf("error %d in blkif_queue_cb\n", error);
cm->bp->bio_error = EIO;
biodone(cm->bp);
xb_free_command(cm);
return;
}
/* Fill out a communications ring structure. */
ring_req = RING_GET_REQUEST(&sc->ring, sc->ring.req_prod_pvt);
sc->ring.req_prod_pvt++;
ring_req->id = cm->id;
ring_req->operation = cm->operation;
ring_req->sector_number = cm->sector_number;
ring_req->handle = (blkif_vdev_t)(uintptr_t)sc->xb_disk;
ring_req->nr_segments = nsegs;
cm->nseg = nsegs;
block_segs = MIN(nsegs, BLKIF_MAX_SEGMENTS_PER_HEADER_BLOCK);
sg = ring_req->seg;
last_block_sg = sg + block_segs;
sg_ref = cm->sg_refs;
while (1) {
while (sg < last_block_sg) {
buffer_ma = segs->ds_addr;
fsect = (buffer_ma & PAGE_MASK) >> XBD_SECTOR_SHFT;
lsect = fsect + (segs->ds_len >> XBD_SECTOR_SHFT) - 1;
KASSERT(lsect <= 7, ("XEN disk driver data cannot "
"cross a page boundary"));
/* install a grant reference. */
ref = gnttab_claim_grant_reference(&cm->gref_head);
/*
* GNTTAB_LIST_END == 0xffffffff, but it is private
* to gnttab.c.
*/
KASSERT(ref != ~0, ("grant_reference failed"));
gnttab_grant_foreign_access_ref(
ref,
xenbus_get_otherend_id(sc->xb_dev),
buffer_ma >> PAGE_SHIFT,
ring_req->operation == BLKIF_OP_WRITE);
*sg_ref = ref;
*sg = (struct blkif_request_segment) {
.gref = ref,
.first_sect = fsect,
.last_sect = lsect };
sg++;
sg_ref++;
segs++;
nsegs--;
}
block_segs = MIN(nsegs, BLKIF_MAX_SEGMENTS_PER_SEGMENT_BLOCK);
if (block_segs == 0)
break;
sg = BLKRING_GET_SEG_BLOCK(&sc->ring, sc->ring.req_prod_pvt);
sc->ring.req_prod_pvt++;
last_block_sg = sg + block_segs;
}
if (cm->operation == BLKIF_OP_READ)
op = BUS_DMASYNC_PREREAD;
else if (cm->operation == BLKIF_OP_WRITE)
op = BUS_DMASYNC_PREWRITE;
else
op = 0;
bus_dmamap_sync(sc->xb_io_dmat, cm->map, op);
gnttab_free_grant_references(cm->gref_head);
xb_enqueue_busy(cm);
/*
* This flag means that we're probably executing in the busdma swi
* instead of in the startio context, so an explicit flush is needed.
*/
if (cm->cm_flags & XB_CMD_FROZEN)
flush_requests(sc);
//printf("%s: Done\n", __func__);
return;
}
/*
* Dequeue buffers and place them in the shared communication ring.
* Return when no more requests can be accepted or all buffers have
* been queued.
*
* Signal XEN once the ring has been filled out.
*/
static void
xb_startio(struct xb_softc *sc)
{
struct xb_command *cm;
int error, queued = 0;
mtx_assert(&sc->xb_io_lock, MA_OWNED);
if (sc->connected != BLKIF_STATE_CONNECTED)
return;
while (RING_FREE_REQUESTS(&sc->ring) >= sc->max_request_blocks) {
if (sc->xb_flags & XB_FROZEN)
break;
cm = xb_dequeue_ready(sc);
if (cm == NULL)
cm = xb_bio_command(sc);
if (cm == NULL)
break;
if ((error = blkif_queue_request(sc, cm)) != 0) {
printf("blkif_queue_request returned %d\n", error);
break;
}
queued++;
}
if (queued != 0)
flush_requests(sc);
}
static void
blkif_int(void *xsc)
{
struct xb_softc *sc = xsc;
struct xb_command *cm;
blkif_response_t *bret;
RING_IDX i, rp;
int op;
mtx_lock(&sc->xb_io_lock);
if (unlikely(sc->connected == BLKIF_STATE_DISCONNECTED)) {
mtx_unlock(&sc->xb_io_lock);
return;
}
again:
rp = sc->ring.sring->rsp_prod;
rmb(); /* Ensure we see queued responses up to 'rp'. */
for (i = sc->ring.rsp_cons; i != rp;) {
bret = RING_GET_RESPONSE(&sc->ring, i);
cm = &sc->shadow[bret->id];
xb_remove_busy(cm);
i += blkif_completion(cm);
if (cm->operation == BLKIF_OP_READ)
op = BUS_DMASYNC_POSTREAD;
else if (cm->operation == BLKIF_OP_WRITE)
op = BUS_DMASYNC_POSTWRITE;
else
op = 0;
bus_dmamap_sync(sc->xb_io_dmat, cm->map, op);
bus_dmamap_unload(sc->xb_io_dmat, cm->map);
/*
* If commands are completing then resources are probably
* being freed as well. It's a cheap assumption even when
* wrong.
*/
sc->xb_flags &= ~XB_FROZEN;
/*
* Directly call the i/o complete routine to save an
* an indirection in the common case.
*/
cm->status = bret->status;
if (cm->bp)
xb_bio_complete(sc, cm);
else if (cm->cm_complete)
(cm->cm_complete)(cm);
else
xb_free_command(cm);
}
sc->ring.rsp_cons = i;
if (i != sc->ring.req_prod_pvt) {
int more_to_do;
RING_FINAL_CHECK_FOR_RESPONSES(&sc->ring, more_to_do);
if (more_to_do)
goto again;
} else {
sc->ring.sring->rsp_event = i + 1;
}
xb_startio(sc);
if (unlikely(sc->connected == BLKIF_STATE_SUSPENDED))
wakeup(&sc->cm_busy);
mtx_unlock(&sc->xb_io_lock);
}
static void
blkif_free(struct xb_softc *sc)
{
uint8_t *sring_page_ptr;
int i;
/* Prevent new requests being issued until we fix things up. */
mtx_lock(&sc->xb_io_lock);
sc->connected = BLKIF_STATE_DISCONNECTED;
mtx_unlock(&sc->xb_io_lock);
/* Free resources associated with old device channel. */
if (sc->ring.sring != NULL) {
sring_page_ptr = (uint8_t *)sc->ring.sring;
for (i = 0; i < sc->ring_pages; i++) {
if (sc->ring_ref[i] != GRANT_INVALID_REF) {
gnttab_end_foreign_access_ref(sc->ring_ref[i]);
sc->ring_ref[i] = GRANT_INVALID_REF;
}
sring_page_ptr += PAGE_SIZE;
}
free(sc->ring.sring, M_XENBLOCKFRONT);
sc->ring.sring = NULL;
}
if (sc->shadow) {
for (i = 0; i < sc->max_requests; i++) {
struct xb_command *cm;
cm = &sc->shadow[i];
if (cm->sg_refs != NULL) {
free(cm->sg_refs, M_XENBLOCKFRONT);
cm->sg_refs = NULL;
}
bus_dmamap_destroy(sc->xb_io_dmat, cm->map);
}
free(sc->shadow, M_XENBLOCKFRONT);
sc->shadow = NULL;
bus_dma_tag_destroy(sc->xb_io_dmat);
xb_initq_free(sc);
xb_initq_ready(sc);
xb_initq_complete(sc);
}
if (sc->irq) {
unbind_from_irqhandler(sc->irq);
sc->irq = 0;
}
}
static int
blkif_completion(struct xb_command *s)
{
//printf("%s: Req %p(%d)\n", __func__, s, s->nseg);
gnttab_end_foreign_access_references(s->nseg, s->sg_refs);
return (BLKIF_SEGS_TO_BLOCKS(s->nseg));
}
/* ** Driver registration ** */
static device_method_t blkfront_methods[] = {
/* Device interface */
DEVMETHOD(device_probe, blkfront_probe),
DEVMETHOD(device_attach, blkfront_attach),
DEVMETHOD(device_detach, blkfront_detach),
DEVMETHOD(device_shutdown, bus_generic_shutdown),
DEVMETHOD(device_suspend, blkfront_suspend),
DEVMETHOD(device_resume, blkfront_resume),
/* Xenbus interface */
DEVMETHOD(xenbus_otherend_changed, blkfront_backend_changed),
{ 0, 0 }
};
static driver_t blkfront_driver = {
"xbd",
blkfront_methods,
sizeof(struct xb_softc),
};
devclass_t blkfront_devclass;
DRIVER_MODULE(xbd, xenbusb_front, blkfront_driver, blkfront_devclass, 0, 0);