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freebsd-dev/sys/dev/xen/blkfront/blkfront.c
Robert Watson 2913e88c91 Make "options XENHVM" compile for i386, not just amd64 -- a largely 
mechanical change.  This opens the door for using PV device drivers
under Xen HVM on i386, as well as more general harmonisation of i386
and amd64 Xen support in FreeBSD.

Reviewed by:    cperciva
MFC after:      3 weeks
2011-01-04 14:49:54 +00:00

1336 lines
32 KiB
C
Raw Blame History

/*
* 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("$FreeBSD$");
#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 <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 *);
#if 0
static void blkif_recover(struct xb_softc *);
#endif
static int blkif_completion(struct xb_command *);
static void blkif_free(struct xb_softc *, int);
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(int 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";
}
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_00);
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);
}
/*
* 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;
int error;
int vdevice;
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, "%i", &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;
/* Front end dir is a number, which is used as the id. */
sc->handle = strtoul(strrchr(xenbus_get_node(dev),'/')+1, NULL, 0);
/* 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);
/* Prevent new requests being issued until we fix things up. */
mtx_lock(&sc->xb_io_lock);
sc->connected = BLKIF_STATE_SUSPENDED;
mtx_unlock(&sc->xb_io_lock);
return (0);
}
static int
blkfront_resume(device_t dev)
{
#if 0
struct xb_softc *sc = device_get_softc(dev);
DPRINTK("blkfront_resume: %s\n", xenbus_get_node(dev));
/* XXX This can't work!!! */
blkif_free(sc, 1);
blkfront_initialize(sc);
if (sc->connected == BLKIF_STATE_SUSPENDED)
blkif_recover(sc);
#endif
return (0);
}
static void
blkfront_initialize(struct xb_softc *sc)
{
const char *otherend_path;
const char *node_path;
int error;
int i;
if (xenbus_get_state(sc->xb_dev) != XenbusStateInitialising)
return;
/*
* Protocol defaults valid even if negotiation for a
* setting fails.
*/
sc->ring_pages = 1;
sc->max_requests = BLKIF_MAX_RING_REQUESTS(PAGE_SIZE);
sc->max_request_segments = BLKIF_MAX_SEGMENTS_PER_HEADER_BLOCK;
sc->max_request_size = (sc->max_request_segments - 1) * PAGE_SIZE;
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.
*/
otherend_path = xenbus_get_otherend_path(sc->xb_dev);
node_path = xenbus_get_node(sc->xb_dev);
(void)xs_scanf(XST_NIL, otherend_path,
"max-ring-pages", NULL, "%" PRIu32,
&sc->ring_pages);
(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 (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 specificed "
"max_requests_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 specificed "
"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;
}
sc->max_request_blocks = BLKIF_SEGS_TO_BLOCKS(sc->max_request_segments);
/* Allocate datastructures based on negotiated values. */
error = bus_dma_tag_create(NULL, /* 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) {
xenbus_dev_fatal(sc->xb_dev, error,
"Cannot allocate request structures\n");
}
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;
error = xs_printf(XST_NIL, node_path,
"ring-pages","%u", sc->ring_pages);
if (error) {
xenbus_dev_fatal(sc->xb_dev, error,
"writing %s/ring-pages",
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);
}
}
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);
}
for (i = 1; 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 int
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:
blkfront_initialize(sc);
break;
case XenbusStateInitialised:
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;
}
return (0);
}
/*
** Invoked when the backend is finally 'ready' (and has told produced
** 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", &sectors,
"info", "%u", &binfo,
"sector-size", "%lu", &sector_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;
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, 0);
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. */
device_t dev = sc->xb_dev;
XenbusState state =
xenbus_read_driver_state(xenbus_get_otherend_path(dev));
if (state == XenbusStateClosing)
blkfront_closing(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_SG_REQUEST(&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);
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_CONNECTED)) {
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);
mtx_unlock(&sc->xb_io_lock);
}
static void
blkif_free(struct xb_softc *sc, int suspend)
{
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 = suspend ?
BLKIF_STATE_SUSPENDED : 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;
}
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));
}
#if 0
static void
blkif_recover(struct xb_softc *sc)
{
/*
* XXX The whole concept of not quiescing and completing all i/o
* during suspend, and then hoping to recover and replay the
* resulting abandoned I/O during resume, is laughable. At best,
* it invalidates the i/o ordering rules required by just about
* every filesystem, and at worst it'll corrupt data. The code
* has been removed until further notice.
*/
}
#endif
/* ** 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);
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