freebsd-nq/sys/dev/virtio/block/virtio_blk.c
2014-06-10 03:29:15 +00:00

1404 lines
32 KiB
C

/*-
* Copyright (c) 2011, Bryan Venteicher <bryanv@FreeBSD.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice unmodified, this list of conditions, and the following
* disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/* Driver for VirtIO block devices. */
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/bio.h>
#include <sys/malloc.h>
#include <sys/module.h>
#include <sys/sglist.h>
#include <sys/sysctl.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/queue.h>
#include <geom/geom_disk.h>
#include <machine/bus.h>
#include <machine/resource.h>
#include <sys/bus.h>
#include <sys/rman.h>
#include <dev/virtio/virtio.h>
#include <dev/virtio/virtqueue.h>
#include <dev/virtio/block/virtio_blk.h>
#include "virtio_if.h"
struct vtblk_request {
struct virtio_blk_outhdr vbr_hdr;
struct bio *vbr_bp;
uint8_t vbr_ack;
TAILQ_ENTRY(vtblk_request) vbr_link;
};
enum vtblk_cache_mode {
VTBLK_CACHE_WRITETHROUGH,
VTBLK_CACHE_WRITEBACK,
VTBLK_CACHE_MAX
};
struct vtblk_softc {
device_t vtblk_dev;
struct mtx vtblk_mtx;
uint64_t vtblk_features;
uint32_t vtblk_flags;
#define VTBLK_FLAG_INDIRECT 0x0001
#define VTBLK_FLAG_READONLY 0x0002
#define VTBLK_FLAG_DETACH 0x0004
#define VTBLK_FLAG_SUSPEND 0x0008
#define VTBLK_FLAG_DUMPING 0x0010
#define VTBLK_FLAG_BARRIER 0x0020
#define VTBLK_FLAG_WC_CONFIG 0x0040
struct virtqueue *vtblk_vq;
struct sglist *vtblk_sglist;
struct disk *vtblk_disk;
struct bio_queue_head vtblk_bioq;
TAILQ_HEAD(, vtblk_request)
vtblk_req_free;
TAILQ_HEAD(, vtblk_request)
vtblk_req_ready;
struct vtblk_request *vtblk_req_ordered;
int vtblk_max_nsegs;
int vtblk_request_count;
enum vtblk_cache_mode vtblk_write_cache;
struct vtblk_request vtblk_dump_request;
};
static struct virtio_feature_desc vtblk_feature_desc[] = {
{ VIRTIO_BLK_F_BARRIER, "HostBarrier" },
{ VIRTIO_BLK_F_SIZE_MAX, "MaxSegSize" },
{ VIRTIO_BLK_F_SEG_MAX, "MaxNumSegs" },
{ VIRTIO_BLK_F_GEOMETRY, "DiskGeometry" },
{ VIRTIO_BLK_F_RO, "ReadOnly" },
{ VIRTIO_BLK_F_BLK_SIZE, "BlockSize" },
{ VIRTIO_BLK_F_SCSI, "SCSICmds" },
{ VIRTIO_BLK_F_WCE, "WriteCache" },
{ VIRTIO_BLK_F_TOPOLOGY, "Topology" },
{ VIRTIO_BLK_F_CONFIG_WCE, "ConfigWCE" },
{ 0, NULL }
};
static int vtblk_modevent(module_t, int, void *);
static int vtblk_probe(device_t);
static int vtblk_attach(device_t);
static int vtblk_detach(device_t);
static int vtblk_suspend(device_t);
static int vtblk_resume(device_t);
static int vtblk_shutdown(device_t);
static int vtblk_config_change(device_t);
static int vtblk_open(struct disk *);
static int vtblk_close(struct disk *);
static int vtblk_ioctl(struct disk *, u_long, void *, int,
struct thread *);
static int vtblk_dump(void *, void *, vm_offset_t, off_t, size_t);
static void vtblk_strategy(struct bio *);
static void vtblk_negotiate_features(struct vtblk_softc *);
static int vtblk_maximum_segments(struct vtblk_softc *,
struct virtio_blk_config *);
static int vtblk_alloc_virtqueue(struct vtblk_softc *);
static void vtblk_resize_disk(struct vtblk_softc *, uint64_t);
static void vtblk_set_write_cache(struct vtblk_softc *, int);
static int vtblk_write_cache_enabled(struct vtblk_softc *sc,
struct virtio_blk_config *);
static int vtblk_write_cache_sysctl(SYSCTL_HANDLER_ARGS);
static void vtblk_alloc_disk(struct vtblk_softc *,
struct virtio_blk_config *);
static void vtblk_create_disk(struct vtblk_softc *);
static int vtblk_quiesce(struct vtblk_softc *);
static void vtblk_startio(struct vtblk_softc *);
static struct vtblk_request * vtblk_bio_request(struct vtblk_softc *);
static int vtblk_execute_request(struct vtblk_softc *,
struct vtblk_request *);
static void vtblk_vq_intr(void *);
static void vtblk_stop(struct vtblk_softc *);
static void vtblk_read_config(struct vtblk_softc *,
struct virtio_blk_config *);
static void vtblk_get_ident(struct vtblk_softc *);
static void vtblk_prepare_dump(struct vtblk_softc *);
static int vtblk_write_dump(struct vtblk_softc *, void *, off_t, size_t);
static int vtblk_flush_dump(struct vtblk_softc *);
static int vtblk_poll_request(struct vtblk_softc *,
struct vtblk_request *);
static void vtblk_finish_completed(struct vtblk_softc *);
static void vtblk_drain_vq(struct vtblk_softc *, int);
static void vtblk_drain(struct vtblk_softc *);
static int vtblk_alloc_requests(struct vtblk_softc *);
static void vtblk_free_requests(struct vtblk_softc *);
static struct vtblk_request * vtblk_dequeue_request(struct vtblk_softc *);
static void vtblk_enqueue_request(struct vtblk_softc *,
struct vtblk_request *);
static struct vtblk_request * vtblk_dequeue_ready(struct vtblk_softc *);
static void vtblk_enqueue_ready(struct vtblk_softc *,
struct vtblk_request *);
static int vtblk_request_error(struct vtblk_request *);
static void vtblk_finish_bio(struct bio *, int);
static void vtblk_setup_sysctl(struct vtblk_softc *);
static int vtblk_tunable_int(struct vtblk_softc *, const char *, int);
/* Tunables. */
static int vtblk_no_ident = 0;
TUNABLE_INT("hw.vtblk.no_ident", &vtblk_no_ident);
static int vtblk_writecache_mode = -1;
TUNABLE_INT("hw.vtblk.writecache_mode", &vtblk_writecache_mode);
/* Features desired/implemented by this driver. */
#define VTBLK_FEATURES \
(VIRTIO_BLK_F_BARRIER | \
VIRTIO_BLK_F_SIZE_MAX | \
VIRTIO_BLK_F_SEG_MAX | \
VIRTIO_BLK_F_GEOMETRY | \
VIRTIO_BLK_F_RO | \
VIRTIO_BLK_F_BLK_SIZE | \
VIRTIO_BLK_F_WCE | \
VIRTIO_BLK_F_CONFIG_WCE | \
VIRTIO_RING_F_INDIRECT_DESC)
#define VTBLK_MTX(_sc) &(_sc)->vtblk_mtx
#define VTBLK_LOCK_INIT(_sc, _name) \
mtx_init(VTBLK_MTX((_sc)), (_name), \
"VirtIO Block Lock", MTX_DEF)
#define VTBLK_LOCK(_sc) mtx_lock(VTBLK_MTX((_sc)))
#define VTBLK_UNLOCK(_sc) mtx_unlock(VTBLK_MTX((_sc)))
#define VTBLK_LOCK_DESTROY(_sc) mtx_destroy(VTBLK_MTX((_sc)))
#define VTBLK_LOCK_ASSERT(_sc) mtx_assert(VTBLK_MTX((_sc)), MA_OWNED)
#define VTBLK_LOCK_ASSERT_NOTOWNED(_sc) \
mtx_assert(VTBLK_MTX((_sc)), MA_NOTOWNED)
#define VTBLK_DISK_NAME "vtbd"
#define VTBLK_QUIESCE_TIMEOUT (30 * hz)
/*
* Each block request uses at least two segments - one for the header
* and one for the status.
*/
#define VTBLK_MIN_SEGMENTS 2
static device_method_t vtblk_methods[] = {
/* Device methods. */
DEVMETHOD(device_probe, vtblk_probe),
DEVMETHOD(device_attach, vtblk_attach),
DEVMETHOD(device_detach, vtblk_detach),
DEVMETHOD(device_suspend, vtblk_suspend),
DEVMETHOD(device_resume, vtblk_resume),
DEVMETHOD(device_shutdown, vtblk_shutdown),
/* VirtIO methods. */
DEVMETHOD(virtio_config_change, vtblk_config_change),
DEVMETHOD_END
};
static driver_t vtblk_driver = {
"vtblk",
vtblk_methods,
sizeof(struct vtblk_softc)
};
static devclass_t vtblk_devclass;
DRIVER_MODULE(virtio_blk, virtio_pci, vtblk_driver, vtblk_devclass,
vtblk_modevent, 0);
MODULE_VERSION(virtio_blk, 1);
MODULE_DEPEND(virtio_blk, virtio, 1, 1, 1);
static int
vtblk_modevent(module_t mod, int type, void *unused)
{
int error;
error = 0;
switch (type) {
case MOD_LOAD:
case MOD_QUIESCE:
case MOD_UNLOAD:
case MOD_SHUTDOWN:
break;
default:
error = EOPNOTSUPP;
break;
}
return (error);
}
static int
vtblk_probe(device_t dev)
{
if (virtio_get_device_type(dev) != VIRTIO_ID_BLOCK)
return (ENXIO);
device_set_desc(dev, "VirtIO Block Adapter");
return (BUS_PROBE_DEFAULT);
}
static int
vtblk_attach(device_t dev)
{
struct vtblk_softc *sc;
struct virtio_blk_config blkcfg;
int error;
sc = device_get_softc(dev);
sc->vtblk_dev = dev;
VTBLK_LOCK_INIT(sc, device_get_nameunit(dev));
bioq_init(&sc->vtblk_bioq);
TAILQ_INIT(&sc->vtblk_req_free);
TAILQ_INIT(&sc->vtblk_req_ready);
virtio_set_feature_desc(dev, vtblk_feature_desc);
vtblk_negotiate_features(sc);
if (virtio_with_feature(dev, VIRTIO_RING_F_INDIRECT_DESC))
sc->vtblk_flags |= VTBLK_FLAG_INDIRECT;
if (virtio_with_feature(dev, VIRTIO_BLK_F_RO))
sc->vtblk_flags |= VTBLK_FLAG_READONLY;
if (virtio_with_feature(dev, VIRTIO_BLK_F_BARRIER))
sc->vtblk_flags |= VTBLK_FLAG_BARRIER;
if (virtio_with_feature(dev, VIRTIO_BLK_F_CONFIG_WCE))
sc->vtblk_flags |= VTBLK_FLAG_WC_CONFIG;
vtblk_setup_sysctl(sc);
/* Get local copy of config. */
vtblk_read_config(sc, &blkcfg);
/*
* With the current sglist(9) implementation, it is not easy
* for us to support a maximum segment size as adjacent
* segments are coalesced. For now, just make sure it's larger
* than the maximum supported transfer size.
*/
if (virtio_with_feature(dev, VIRTIO_BLK_F_SIZE_MAX)) {
if (blkcfg.size_max < MAXPHYS) {
error = ENOTSUP;
device_printf(dev, "host requires unsupported "
"maximum segment size feature\n");
goto fail;
}
}
sc->vtblk_max_nsegs = vtblk_maximum_segments(sc, &blkcfg);
if (sc->vtblk_max_nsegs <= VTBLK_MIN_SEGMENTS) {
error = EINVAL;
device_printf(dev, "fewer than minimum number of segments "
"allowed: %d\n", sc->vtblk_max_nsegs);
goto fail;
}
sc->vtblk_sglist = sglist_alloc(sc->vtblk_max_nsegs, M_NOWAIT);
if (sc->vtblk_sglist == NULL) {
error = ENOMEM;
device_printf(dev, "cannot allocate sglist\n");
goto fail;
}
error = vtblk_alloc_virtqueue(sc);
if (error) {
device_printf(dev, "cannot allocate virtqueue\n");
goto fail;
}
error = vtblk_alloc_requests(sc);
if (error) {
device_printf(dev, "cannot preallocate requests\n");
goto fail;
}
vtblk_alloc_disk(sc, &blkcfg);
error = virtio_setup_intr(dev, INTR_TYPE_BIO | INTR_ENTROPY);
if (error) {
device_printf(dev, "cannot setup virtqueue interrupt\n");
goto fail;
}
vtblk_create_disk(sc);
virtqueue_enable_intr(sc->vtblk_vq);
fail:
if (error)
vtblk_detach(dev);
return (error);
}
static int
vtblk_detach(device_t dev)
{
struct vtblk_softc *sc;
sc = device_get_softc(dev);
VTBLK_LOCK(sc);
sc->vtblk_flags |= VTBLK_FLAG_DETACH;
if (device_is_attached(dev))
vtblk_stop(sc);
VTBLK_UNLOCK(sc);
vtblk_drain(sc);
if (sc->vtblk_disk != NULL) {
disk_destroy(sc->vtblk_disk);
sc->vtblk_disk = NULL;
}
if (sc->vtblk_sglist != NULL) {
sglist_free(sc->vtblk_sglist);
sc->vtblk_sglist = NULL;
}
VTBLK_LOCK_DESTROY(sc);
return (0);
}
static int
vtblk_suspend(device_t dev)
{
struct vtblk_softc *sc;
int error;
sc = device_get_softc(dev);
VTBLK_LOCK(sc);
sc->vtblk_flags |= VTBLK_FLAG_SUSPEND;
/* XXX BMV: virtio_stop(), etc needed here? */
error = vtblk_quiesce(sc);
if (error)
sc->vtblk_flags &= ~VTBLK_FLAG_SUSPEND;
VTBLK_UNLOCK(sc);
return (error);
}
static int
vtblk_resume(device_t dev)
{
struct vtblk_softc *sc;
sc = device_get_softc(dev);
VTBLK_LOCK(sc);
/* XXX BMV: virtio_reinit(), etc needed here? */
sc->vtblk_flags &= ~VTBLK_FLAG_SUSPEND;
vtblk_startio(sc);
VTBLK_UNLOCK(sc);
return (0);
}
static int
vtblk_shutdown(device_t dev)
{
return (0);
}
static int
vtblk_config_change(device_t dev)
{
struct vtblk_softc *sc;
struct virtio_blk_config blkcfg;
uint64_t capacity;
sc = device_get_softc(dev);
vtblk_read_config(sc, &blkcfg);
/* Capacity is always in 512-byte units. */
capacity = blkcfg.capacity * 512;
if (sc->vtblk_disk->d_mediasize != capacity)
vtblk_resize_disk(sc, capacity);
return (0);
}
static int
vtblk_open(struct disk *dp)
{
struct vtblk_softc *sc;
if ((sc = dp->d_drv1) == NULL)
return (ENXIO);
return (sc->vtblk_flags & VTBLK_FLAG_DETACH ? ENXIO : 0);
}
static int
vtblk_close(struct disk *dp)
{
struct vtblk_softc *sc;
if ((sc = dp->d_drv1) == NULL)
return (ENXIO);
return (0);
}
static int
vtblk_ioctl(struct disk *dp, u_long cmd, void *addr, int flag,
struct thread *td)
{
struct vtblk_softc *sc;
if ((sc = dp->d_drv1) == NULL)
return (ENXIO);
return (ENOTTY);
}
static int
vtblk_dump(void *arg, void *virtual, vm_offset_t physical, off_t offset,
size_t length)
{
struct disk *dp;
struct vtblk_softc *sc;
int error;
dp = arg;
if ((sc = dp->d_drv1) == NULL)
return (ENXIO);
VTBLK_LOCK(sc);
if ((sc->vtblk_flags & VTBLK_FLAG_DUMPING) == 0) {
vtblk_prepare_dump(sc);
sc->vtblk_flags |= VTBLK_FLAG_DUMPING;
}
if (length > 0)
error = vtblk_write_dump(sc, virtual, offset, length);
else if (virtual == NULL && offset == 0)
error = vtblk_flush_dump(sc);
else {
error = EINVAL;
sc->vtblk_flags &= ~VTBLK_FLAG_DUMPING;
}
VTBLK_UNLOCK(sc);
return (error);
}
static void
vtblk_strategy(struct bio *bp)
{
struct vtblk_softc *sc;
if ((sc = bp->bio_disk->d_drv1) == NULL) {
vtblk_finish_bio(bp, EINVAL);
return;
}
/*
* Fail any write if RO. Unfortunately, there does not seem to
* be a better way to report our readonly'ness to GEOM above.
*/
if (sc->vtblk_flags & VTBLK_FLAG_READONLY &&
(bp->bio_cmd == BIO_WRITE || bp->bio_cmd == BIO_FLUSH)) {
vtblk_finish_bio(bp, EROFS);
return;
}
#ifdef INVARIANTS
/*
* Prevent read/write buffers spanning too many segments from
* getting into the queue. This should only trip if d_maxsize
* was incorrectly set.
*/
if (bp->bio_cmd == BIO_READ || bp->bio_cmd == BIO_WRITE) {
int nsegs, max_nsegs;
nsegs = sglist_count(bp->bio_data, bp->bio_bcount);
max_nsegs = sc->vtblk_max_nsegs - VTBLK_MIN_SEGMENTS;
KASSERT(nsegs <= max_nsegs,
("%s: bio %p spanned too many segments: %d, max: %d",
__func__, bp, nsegs, max_nsegs));
}
#endif
VTBLK_LOCK(sc);
if (sc->vtblk_flags & VTBLK_FLAG_DETACH)
vtblk_finish_bio(bp, ENXIO);
else {
bioq_insert_tail(&sc->vtblk_bioq, bp);
if ((sc->vtblk_flags & VTBLK_FLAG_SUSPEND) == 0)
vtblk_startio(sc);
}
VTBLK_UNLOCK(sc);
}
static void
vtblk_negotiate_features(struct vtblk_softc *sc)
{
device_t dev;
uint64_t features;
dev = sc->vtblk_dev;
features = VTBLK_FEATURES;
sc->vtblk_features = virtio_negotiate_features(dev, features);
}
static int
vtblk_maximum_segments(struct vtblk_softc *sc,
struct virtio_blk_config *blkcfg)
{
device_t dev;
int nsegs;
dev = sc->vtblk_dev;
nsegs = VTBLK_MIN_SEGMENTS;
if (virtio_with_feature(dev, VIRTIO_BLK_F_SEG_MAX)) {
nsegs += MIN(blkcfg->seg_max, MAXPHYS / PAGE_SIZE + 1);
if (sc->vtblk_flags & VTBLK_FLAG_INDIRECT)
nsegs = MIN(nsegs, VIRTIO_MAX_INDIRECT);
} else
nsegs += 1;
return (nsegs);
}
static int
vtblk_alloc_virtqueue(struct vtblk_softc *sc)
{
device_t dev;
struct vq_alloc_info vq_info;
dev = sc->vtblk_dev;
VQ_ALLOC_INFO_INIT(&vq_info, sc->vtblk_max_nsegs,
vtblk_vq_intr, sc, &sc->vtblk_vq,
"%s request", device_get_nameunit(dev));
return (virtio_alloc_virtqueues(dev, 0, 1, &vq_info));
}
static void
vtblk_resize_disk(struct vtblk_softc *sc, uint64_t new_capacity)
{
device_t dev;
struct disk *dp;
int error;
dev = sc->vtblk_dev;
dp = sc->vtblk_disk;
dp->d_mediasize = new_capacity;
if (bootverbose) {
device_printf(dev, "resized to %juMB (%ju %u byte sectors)\n",
(uintmax_t) dp->d_mediasize >> 20,
(uintmax_t) dp->d_mediasize / dp->d_sectorsize,
dp->d_sectorsize);
}
error = disk_resize(dp, M_NOWAIT);
if (error) {
device_printf(dev,
"disk_resize(9) failed, error: %d\n", error);
}
}
static void
vtblk_set_write_cache(struct vtblk_softc *sc, int wc)
{
/* Set either writeback (1) or writethrough (0) mode. */
virtio_write_dev_config_1(sc->vtblk_dev,
offsetof(struct virtio_blk_config, writeback), wc);
}
static int
vtblk_write_cache_enabled(struct vtblk_softc *sc,
struct virtio_blk_config *blkcfg)
{
int wc;
if (sc->vtblk_flags & VTBLK_FLAG_WC_CONFIG) {
wc = vtblk_tunable_int(sc, "writecache_mode",
vtblk_writecache_mode);
if (wc >= 0 && wc < VTBLK_CACHE_MAX)
vtblk_set_write_cache(sc, wc);
else
wc = blkcfg->writeback;
} else
wc = virtio_with_feature(sc->vtblk_dev, VIRTIO_BLK_F_WCE);
return (wc);
}
static int
vtblk_write_cache_sysctl(SYSCTL_HANDLER_ARGS)
{
struct vtblk_softc *sc;
int wc, error;
sc = oidp->oid_arg1;
wc = sc->vtblk_write_cache;
error = sysctl_handle_int(oidp, &wc, 0, req);
if (error || req->newptr == NULL)
return (error);
if ((sc->vtblk_flags & VTBLK_FLAG_WC_CONFIG) == 0)
return (EPERM);
if (wc < 0 || wc >= VTBLK_CACHE_MAX)
return (EINVAL);
VTBLK_LOCK(sc);
sc->vtblk_write_cache = wc;
vtblk_set_write_cache(sc, sc->vtblk_write_cache);
VTBLK_UNLOCK(sc);
return (0);
}
static void
vtblk_alloc_disk(struct vtblk_softc *sc, struct virtio_blk_config *blkcfg)
{
device_t dev;
struct disk *dp;
dev = sc->vtblk_dev;
sc->vtblk_disk = dp = disk_alloc();
dp->d_open = vtblk_open;
dp->d_close = vtblk_close;
dp->d_ioctl = vtblk_ioctl;
dp->d_strategy = vtblk_strategy;
dp->d_name = VTBLK_DISK_NAME;
dp->d_unit = device_get_unit(dev);
dp->d_drv1 = sc;
dp->d_flags = DISKFLAG_CANFLUSHCACHE | DISKFLAG_UNMAPPED_BIO;
dp->d_hba_vendor = virtio_get_vendor(dev);
dp->d_hba_device = virtio_get_device(dev);
dp->d_hba_subvendor = virtio_get_subvendor(dev);
dp->d_hba_subdevice = virtio_get_subdevice(dev);
if ((sc->vtblk_flags & VTBLK_FLAG_READONLY) == 0)
dp->d_dump = vtblk_dump;
/* Capacity is always in 512-byte units. */
dp->d_mediasize = blkcfg->capacity * 512;
if (virtio_with_feature(dev, VIRTIO_BLK_F_BLK_SIZE))
dp->d_sectorsize = blkcfg->blk_size;
else
dp->d_sectorsize = 512;
/*
* The VirtIO maximum I/O size is given in terms of segments.
* However, FreeBSD limits I/O size by logical buffer size, not
* by physically contiguous pages. Therefore, we have to assume
* no pages are contiguous. This may impose an artificially low
* maximum I/O size. But in practice, since QEMU advertises 128
* segments, this gives us a maximum IO size of 125 * PAGE_SIZE,
* which is typically greater than MAXPHYS. Eventually we should
* just advertise MAXPHYS and split buffers that are too big.
*
* Note we must subtract one additional segment in case of non
* page aligned buffers.
*/
dp->d_maxsize = (sc->vtblk_max_nsegs - VTBLK_MIN_SEGMENTS - 1) *
PAGE_SIZE;
if (dp->d_maxsize < PAGE_SIZE)
dp->d_maxsize = PAGE_SIZE; /* XXX */
if (virtio_with_feature(dev, VIRTIO_BLK_F_GEOMETRY)) {
dp->d_fwsectors = blkcfg->geometry.sectors;
dp->d_fwheads = blkcfg->geometry.heads;
}
if (virtio_with_feature(dev, VIRTIO_BLK_F_TOPOLOGY)) {
dp->d_stripesize = dp->d_sectorsize *
(1 << blkcfg->topology.physical_block_exp);
dp->d_stripeoffset = (dp->d_stripesize -
blkcfg->topology.alignment_offset * dp->d_sectorsize) %
dp->d_stripesize;
}
if (vtblk_write_cache_enabled(sc, blkcfg) != 0)
sc->vtblk_write_cache = VTBLK_CACHE_WRITEBACK;
else
sc->vtblk_write_cache = VTBLK_CACHE_WRITETHROUGH;
}
static void
vtblk_create_disk(struct vtblk_softc *sc)
{
struct disk *dp;
dp = sc->vtblk_disk;
/*
* Retrieving the identification string must be done after
* the virtqueue interrupt is setup otherwise it will hang.
*/
vtblk_get_ident(sc);
device_printf(sc->vtblk_dev, "%juMB (%ju %u byte sectors)\n",
(uintmax_t) dp->d_mediasize >> 20,
(uintmax_t) dp->d_mediasize / dp->d_sectorsize,
dp->d_sectorsize);
disk_create(dp, DISK_VERSION);
}
static int
vtblk_quiesce(struct vtblk_softc *sc)
{
int error;
error = 0;
VTBLK_LOCK_ASSERT(sc);
while (!virtqueue_empty(sc->vtblk_vq)) {
if (mtx_sleep(&sc->vtblk_vq, VTBLK_MTX(sc), PRIBIO, "vtblkq",
VTBLK_QUIESCE_TIMEOUT) == EWOULDBLOCK) {
error = EBUSY;
break;
}
}
return (error);
}
static void
vtblk_startio(struct vtblk_softc *sc)
{
struct virtqueue *vq;
struct vtblk_request *req;
int enq;
vq = sc->vtblk_vq;
enq = 0;
VTBLK_LOCK_ASSERT(sc);
while (!virtqueue_full(vq)) {
if ((req = vtblk_dequeue_ready(sc)) == NULL)
req = vtblk_bio_request(sc);
if (req == NULL)
break;
if (vtblk_execute_request(sc, req) != 0) {
vtblk_enqueue_ready(sc, req);
break;
}
enq++;
}
if (enq > 0)
virtqueue_notify(vq);
}
static struct vtblk_request *
vtblk_bio_request(struct vtblk_softc *sc)
{
struct bio_queue_head *bioq;
struct vtblk_request *req;
struct bio *bp;
bioq = &sc->vtblk_bioq;
if (bioq_first(bioq) == NULL)
return (NULL);
req = vtblk_dequeue_request(sc);
if (req == NULL)
return (NULL);
bp = bioq_takefirst(bioq);
req->vbr_bp = bp;
req->vbr_ack = -1;
req->vbr_hdr.ioprio = 1;
switch (bp->bio_cmd) {
case BIO_FLUSH:
req->vbr_hdr.type = VIRTIO_BLK_T_FLUSH;
break;
case BIO_READ:
req->vbr_hdr.type = VIRTIO_BLK_T_IN;
req->vbr_hdr.sector = bp->bio_offset / 512;
break;
case BIO_WRITE:
req->vbr_hdr.type = VIRTIO_BLK_T_OUT;
req->vbr_hdr.sector = bp->bio_offset / 512;
break;
default:
panic("%s: bio with unhandled cmd: %d", __func__, bp->bio_cmd);
}
return (req);
}
static int
vtblk_execute_request(struct vtblk_softc *sc, struct vtblk_request *req)
{
struct virtqueue *vq;
struct sglist *sg;
struct bio *bp;
int ordered, readable, writable, error;
vq = sc->vtblk_vq;
sg = sc->vtblk_sglist;
bp = req->vbr_bp;
ordered = 0;
writable = 0;
VTBLK_LOCK_ASSERT(sc);
/*
* Wait until the ordered request completes before
* executing subsequent requests.
*/
if (sc->vtblk_req_ordered != NULL)
return (EBUSY);
if (bp->bio_flags & BIO_ORDERED) {
if ((sc->vtblk_flags & VTBLK_FLAG_BARRIER) == 0) {
/*
* This request will be executed once all
* the in-flight requests are completed.
*/
if (!virtqueue_empty(vq))
return (EBUSY);
ordered = 1;
} else
req->vbr_hdr.type |= VIRTIO_BLK_T_BARRIER;
}
sglist_reset(sg);
sglist_append(sg, &req->vbr_hdr, sizeof(struct virtio_blk_outhdr));
if (bp->bio_cmd == BIO_READ || bp->bio_cmd == BIO_WRITE) {
error = sglist_append_bio(sg, bp);
if (error || sg->sg_nseg == sg->sg_maxseg) {
panic("%s: data buffer too big bio:%p error:%d",
__func__, bp, error);
}
/* BIO_READ means the host writes into our buffer. */
if (bp->bio_cmd == BIO_READ)
writable = sg->sg_nseg - 1;
}
writable++;
sglist_append(sg, &req->vbr_ack, sizeof(uint8_t));
readable = sg->sg_nseg - writable;
error = virtqueue_enqueue(vq, req, sg, readable, writable);
if (error == 0 && ordered)
sc->vtblk_req_ordered = req;
return (error);
}
static void
vtblk_vq_intr(void *xsc)
{
struct vtblk_softc *sc;
struct virtqueue *vq;
sc = xsc;
vq = sc->vtblk_vq;
again:
VTBLK_LOCK(sc);
if (sc->vtblk_flags & VTBLK_FLAG_DETACH) {
VTBLK_UNLOCK(sc);
return;
}
vtblk_finish_completed(sc);
if ((sc->vtblk_flags & VTBLK_FLAG_SUSPEND) == 0)
vtblk_startio(sc);
else
wakeup(&sc->vtblk_vq);
if (virtqueue_enable_intr(vq) != 0) {
virtqueue_disable_intr(vq);
VTBLK_UNLOCK(sc);
goto again;
}
VTBLK_UNLOCK(sc);
}
static void
vtblk_stop(struct vtblk_softc *sc)
{
virtqueue_disable_intr(sc->vtblk_vq);
virtio_stop(sc->vtblk_dev);
}
#define VTBLK_GET_CONFIG(_dev, _feature, _field, _cfg) \
if (virtio_with_feature(_dev, _feature)) { \
virtio_read_device_config(_dev, \
offsetof(struct virtio_blk_config, _field), \
&(_cfg)->_field, sizeof((_cfg)->_field)); \
}
static void
vtblk_read_config(struct vtblk_softc *sc, struct virtio_blk_config *blkcfg)
{
device_t dev;
dev = sc->vtblk_dev;
bzero(blkcfg, sizeof(struct virtio_blk_config));
/* The capacity is always available. */
virtio_read_device_config(dev, offsetof(struct virtio_blk_config,
capacity), &blkcfg->capacity, sizeof(blkcfg->capacity));
/* Read the configuration if the feature was negotiated. */
VTBLK_GET_CONFIG(dev, VIRTIO_BLK_F_SIZE_MAX, size_max, blkcfg);
VTBLK_GET_CONFIG(dev, VIRTIO_BLK_F_SEG_MAX, seg_max, blkcfg);
VTBLK_GET_CONFIG(dev, VIRTIO_BLK_F_GEOMETRY, geometry, blkcfg);
VTBLK_GET_CONFIG(dev, VIRTIO_BLK_F_BLK_SIZE, blk_size, blkcfg);
VTBLK_GET_CONFIG(dev, VIRTIO_BLK_F_TOPOLOGY, topology, blkcfg);
VTBLK_GET_CONFIG(dev, VIRTIO_BLK_F_CONFIG_WCE, writeback, blkcfg);
}
#undef VTBLK_GET_CONFIG
static void
vtblk_get_ident(struct vtblk_softc *sc)
{
struct bio buf;
struct disk *dp;
struct vtblk_request *req;
int len, error;
dp = sc->vtblk_disk;
len = MIN(VIRTIO_BLK_ID_BYTES, DISK_IDENT_SIZE);
if (vtblk_tunable_int(sc, "no_ident", vtblk_no_ident) != 0)
return;
req = vtblk_dequeue_request(sc);
if (req == NULL)
return;
req->vbr_ack = -1;
req->vbr_hdr.type = VIRTIO_BLK_T_GET_ID;
req->vbr_hdr.ioprio = 1;
req->vbr_hdr.sector = 0;
req->vbr_bp = &buf;
bzero(&buf, sizeof(struct bio));
buf.bio_cmd = BIO_READ;
buf.bio_data = dp->d_ident;
buf.bio_bcount = len;
VTBLK_LOCK(sc);
error = vtblk_poll_request(sc, req);
VTBLK_UNLOCK(sc);
vtblk_enqueue_request(sc, req);
if (error) {
device_printf(sc->vtblk_dev,
"error getting device identifier: %d\n", error);
}
}
static void
vtblk_prepare_dump(struct vtblk_softc *sc)
{
device_t dev;
struct virtqueue *vq;
dev = sc->vtblk_dev;
vq = sc->vtblk_vq;
vtblk_stop(sc);
/*
* Drain all requests caught in-flight in the virtqueue,
* skipping biodone(). When dumping, only one request is
* outstanding at a time, and we just poll the virtqueue
* for the response.
*/
vtblk_drain_vq(sc, 1);
if (virtio_reinit(dev, sc->vtblk_features) != 0) {
panic("%s: cannot reinit VirtIO block device during dump",
device_get_nameunit(dev));
}
virtqueue_disable_intr(vq);
virtio_reinit_complete(dev);
}
static int
vtblk_write_dump(struct vtblk_softc *sc, void *virtual, off_t offset,
size_t length)
{
struct bio buf;
struct vtblk_request *req;
req = &sc->vtblk_dump_request;
req->vbr_ack = -1;
req->vbr_hdr.type = VIRTIO_BLK_T_OUT;
req->vbr_hdr.ioprio = 1;
req->vbr_hdr.sector = offset / 512;
req->vbr_bp = &buf;
bzero(&buf, sizeof(struct bio));
buf.bio_cmd = BIO_WRITE;
buf.bio_data = virtual;
buf.bio_bcount = length;
return (vtblk_poll_request(sc, req));
}
static int
vtblk_flush_dump(struct vtblk_softc *sc)
{
struct bio buf;
struct vtblk_request *req;
req = &sc->vtblk_dump_request;
req->vbr_ack = -1;
req->vbr_hdr.type = VIRTIO_BLK_T_FLUSH;
req->vbr_hdr.ioprio = 1;
req->vbr_hdr.sector = 0;
req->vbr_bp = &buf;
bzero(&buf, sizeof(struct bio));
buf.bio_cmd = BIO_FLUSH;
return (vtblk_poll_request(sc, req));
}
static int
vtblk_poll_request(struct vtblk_softc *sc, struct vtblk_request *req)
{
struct virtqueue *vq;
int error;
vq = sc->vtblk_vq;
if (!virtqueue_empty(vq))
return (EBUSY);
error = vtblk_execute_request(sc, req);
if (error)
return (error);
virtqueue_notify(vq);
virtqueue_poll(vq, NULL);
error = vtblk_request_error(req);
if (error && bootverbose) {
device_printf(sc->vtblk_dev,
"%s: IO error: %d\n", __func__, error);
}
return (error);
}
static void
vtblk_finish_completed(struct vtblk_softc *sc)
{
struct vtblk_request *req;
struct bio *bp;
int error;
while ((req = virtqueue_dequeue(sc->vtblk_vq, NULL)) != NULL) {
bp = req->vbr_bp;
if (sc->vtblk_req_ordered != NULL) {
/* This should be the only outstanding request. */
MPASS(sc->vtblk_req_ordered == req);
sc->vtblk_req_ordered = NULL;
}
error = vtblk_request_error(req);
if (error)
disk_err(bp, "hard error", -1, 1);
vtblk_finish_bio(bp, error);
vtblk_enqueue_request(sc, req);
}
}
static void
vtblk_drain_vq(struct vtblk_softc *sc, int skip_done)
{
struct virtqueue *vq;
struct vtblk_request *req;
int last;
vq = sc->vtblk_vq;
last = 0;
while ((req = virtqueue_drain(vq, &last)) != NULL) {
if (!skip_done)
vtblk_finish_bio(req->vbr_bp, ENXIO);
vtblk_enqueue_request(sc, req);
}
sc->vtblk_req_ordered = NULL;
KASSERT(virtqueue_empty(vq), ("virtqueue not empty"));
}
static void
vtblk_drain(struct vtblk_softc *sc)
{
struct bio_queue_head *bioq;
struct vtblk_request *req;
struct bio *bp;
bioq = &sc->vtblk_bioq;
if (sc->vtblk_vq != NULL) {
vtblk_finish_completed(sc);
vtblk_drain_vq(sc, 0);
}
while ((req = vtblk_dequeue_ready(sc)) != NULL) {
vtblk_finish_bio(req->vbr_bp, ENXIO);
vtblk_enqueue_request(sc, req);
}
while (bioq_first(bioq) != NULL) {
bp = bioq_takefirst(bioq);
vtblk_finish_bio(bp, ENXIO);
}
vtblk_free_requests(sc);
}
#ifdef INVARIANTS
static void
vtblk_request_invariants(struct vtblk_request *req)
{
int hdr_nsegs, ack_nsegs;
hdr_nsegs = sglist_count(&req->vbr_hdr, sizeof(req->vbr_hdr));
ack_nsegs = sglist_count(&req->vbr_ack, sizeof(req->vbr_ack));
KASSERT(hdr_nsegs == 1, ("request header crossed page boundary"));
KASSERT(ack_nsegs == 1, ("request ack crossed page boundary"));
}
#endif
static int
vtblk_alloc_requests(struct vtblk_softc *sc)
{
struct vtblk_request *req;
int i, nreqs;
nreqs = virtqueue_size(sc->vtblk_vq);
/*
* Preallocate sufficient requests to keep the virtqueue full. Each
* request consumes VTBLK_MIN_SEGMENTS or more descriptors so reduce
* the number allocated when indirect descriptors are not available.
*/
if ((sc->vtblk_flags & VTBLK_FLAG_INDIRECT) == 0)
nreqs /= VTBLK_MIN_SEGMENTS;
for (i = 0; i < nreqs; i++) {
req = malloc(sizeof(struct vtblk_request), M_DEVBUF, M_NOWAIT);
if (req == NULL)
return (ENOMEM);
#ifdef INVARIANTS
vtblk_request_invariants(req);
#endif
sc->vtblk_request_count++;
vtblk_enqueue_request(sc, req);
}
return (0);
}
static void
vtblk_free_requests(struct vtblk_softc *sc)
{
struct vtblk_request *req;
KASSERT(TAILQ_EMPTY(&sc->vtblk_req_ready),
("%s: ready requests left on queue", __func__));
while ((req = vtblk_dequeue_request(sc)) != NULL) {
sc->vtblk_request_count--;
free(req, M_DEVBUF);
}
KASSERT(sc->vtblk_request_count == 0,
("%s: leaked %d requests", __func__, sc->vtblk_request_count));
}
static struct vtblk_request *
vtblk_dequeue_request(struct vtblk_softc *sc)
{
struct vtblk_request *req;
req = TAILQ_FIRST(&sc->vtblk_req_free);
if (req != NULL)
TAILQ_REMOVE(&sc->vtblk_req_free, req, vbr_link);
return (req);
}
static void
vtblk_enqueue_request(struct vtblk_softc *sc, struct vtblk_request *req)
{
bzero(req, sizeof(struct vtblk_request));
TAILQ_INSERT_HEAD(&sc->vtblk_req_free, req, vbr_link);
}
static struct vtblk_request *
vtblk_dequeue_ready(struct vtblk_softc *sc)
{
struct vtblk_request *req;
req = TAILQ_FIRST(&sc->vtblk_req_ready);
if (req != NULL)
TAILQ_REMOVE(&sc->vtblk_req_ready, req, vbr_link);
return (req);
}
static void
vtblk_enqueue_ready(struct vtblk_softc *sc, struct vtblk_request *req)
{
TAILQ_INSERT_HEAD(&sc->vtblk_req_ready, req, vbr_link);
}
static int
vtblk_request_error(struct vtblk_request *req)
{
int error;
switch (req->vbr_ack) {
case VIRTIO_BLK_S_OK:
error = 0;
break;
case VIRTIO_BLK_S_UNSUPP:
error = ENOTSUP;
break;
default:
error = EIO;
break;
}
return (error);
}
static void
vtblk_finish_bio(struct bio *bp, int error)
{
if (error) {
bp->bio_resid = bp->bio_bcount;
bp->bio_error = error;
bp->bio_flags |= BIO_ERROR;
}
biodone(bp);
}
static void
vtblk_setup_sysctl(struct vtblk_softc *sc)
{
device_t dev;
struct sysctl_ctx_list *ctx;
struct sysctl_oid *tree;
struct sysctl_oid_list *child;
dev = sc->vtblk_dev;
ctx = device_get_sysctl_ctx(dev);
tree = device_get_sysctl_tree(dev);
child = SYSCTL_CHILDREN(tree);
SYSCTL_ADD_PROC(ctx, child, OID_AUTO, "writecache_mode",
CTLTYPE_INT | CTLFLAG_RW, sc, 0, vtblk_write_cache_sysctl,
"I", "Write cache mode (writethrough (0) or writeback (1))");
}
static int
vtblk_tunable_int(struct vtblk_softc *sc, const char *knob, int def)
{
char path[64];
snprintf(path, sizeof(path),
"hw.vtblk.%d.%s", device_get_unit(sc->vtblk_dev), knob);
TUNABLE_INT_FETCH(path, &def);
return (def);
}