linux/drivers/block/virtio_blk.c
Xie Yongji 82e89ea077 virtio-blk: Add validation for block size in config space
An untrusted device might presents an invalid block size
in configuration space. This tries to add validation for it
in the validate callback and clear the VIRTIO_BLK_F_BLK_SIZE
feature bit if the value is out of the supported range.

And we also double check the value in virtblk_probe() in
case that it's changed after the validation.

Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
Link: https://lore.kernel.org/r/20210809101609.148-1-xieyongji@bytedance.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
2021-08-11 06:44:24 -04:00

1060 lines
26 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
//#define DEBUG
#include <linux/spinlock.h>
#include <linux/slab.h>
#include <linux/blkdev.h>
#include <linux/hdreg.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/interrupt.h>
#include <linux/virtio.h>
#include <linux/virtio_blk.h>
#include <linux/scatterlist.h>
#include <linux/string_helpers.h>
#include <linux/idr.h>
#include <linux/blk-mq.h>
#include <linux/blk-mq-virtio.h>
#include <linux/numa.h>
#include <uapi/linux/virtio_ring.h>
#define PART_BITS 4
#define VQ_NAME_LEN 16
#define MAX_DISCARD_SEGMENTS 256u
/* The maximum number of sg elements that fit into a virtqueue */
#define VIRTIO_BLK_MAX_SG_ELEMS 32768
static int major;
static DEFINE_IDA(vd_index_ida);
static struct workqueue_struct *virtblk_wq;
struct virtio_blk_vq {
struct virtqueue *vq;
spinlock_t lock;
char name[VQ_NAME_LEN];
} ____cacheline_aligned_in_smp;
struct virtio_blk {
/*
* This mutex must be held by anything that may run after
* virtblk_remove() sets vblk->vdev to NULL.
*
* blk-mq, virtqueue processing, and sysfs attribute code paths are
* shut down before vblk->vdev is set to NULL and therefore do not need
* to hold this mutex.
*/
struct mutex vdev_mutex;
struct virtio_device *vdev;
/* The disk structure for the kernel. */
struct gendisk *disk;
/* Block layer tags. */
struct blk_mq_tag_set tag_set;
/* Process context for config space updates */
struct work_struct config_work;
/*
* Tracks references from block_device_operations open/release and
* virtio_driver probe/remove so this object can be freed once no
* longer in use.
*/
refcount_t refs;
/* What host tells us, plus 2 for header & tailer. */
unsigned int sg_elems;
/* Ida index - used to track minor number allocations. */
int index;
/* num of vqs */
int num_vqs;
struct virtio_blk_vq *vqs;
};
struct virtblk_req {
struct virtio_blk_outhdr out_hdr;
u8 status;
struct scatterlist sg[];
};
static inline blk_status_t virtblk_result(struct virtblk_req *vbr)
{
switch (vbr->status) {
case VIRTIO_BLK_S_OK:
return BLK_STS_OK;
case VIRTIO_BLK_S_UNSUPP:
return BLK_STS_NOTSUPP;
default:
return BLK_STS_IOERR;
}
}
static int virtblk_add_req(struct virtqueue *vq, struct virtblk_req *vbr,
struct scatterlist *data_sg, bool have_data)
{
struct scatterlist hdr, status, *sgs[3];
unsigned int num_out = 0, num_in = 0;
sg_init_one(&hdr, &vbr->out_hdr, sizeof(vbr->out_hdr));
sgs[num_out++] = &hdr;
if (have_data) {
if (vbr->out_hdr.type & cpu_to_virtio32(vq->vdev, VIRTIO_BLK_T_OUT))
sgs[num_out++] = data_sg;
else
sgs[num_out + num_in++] = data_sg;
}
sg_init_one(&status, &vbr->status, sizeof(vbr->status));
sgs[num_out + num_in++] = &status;
return virtqueue_add_sgs(vq, sgs, num_out, num_in, vbr, GFP_ATOMIC);
}
static int virtblk_setup_discard_write_zeroes(struct request *req, bool unmap)
{
unsigned short segments = blk_rq_nr_discard_segments(req);
unsigned short n = 0;
struct virtio_blk_discard_write_zeroes *range;
struct bio *bio;
u32 flags = 0;
if (unmap)
flags |= VIRTIO_BLK_WRITE_ZEROES_FLAG_UNMAP;
range = kmalloc_array(segments, sizeof(*range), GFP_ATOMIC);
if (!range)
return -ENOMEM;
/*
* Single max discard segment means multi-range discard isn't
* supported, and block layer only runs contiguity merge like
* normal RW request. So we can't reply on bio for retrieving
* each range info.
*/
if (queue_max_discard_segments(req->q) == 1) {
range[0].flags = cpu_to_le32(flags);
range[0].num_sectors = cpu_to_le32(blk_rq_sectors(req));
range[0].sector = cpu_to_le64(blk_rq_pos(req));
n = 1;
} else {
__rq_for_each_bio(bio, req) {
u64 sector = bio->bi_iter.bi_sector;
u32 num_sectors = bio->bi_iter.bi_size >> SECTOR_SHIFT;
range[n].flags = cpu_to_le32(flags);
range[n].num_sectors = cpu_to_le32(num_sectors);
range[n].sector = cpu_to_le64(sector);
n++;
}
}
WARN_ON_ONCE(n != segments);
req->special_vec.bv_page = virt_to_page(range);
req->special_vec.bv_offset = offset_in_page(range);
req->special_vec.bv_len = sizeof(*range) * segments;
req->rq_flags |= RQF_SPECIAL_PAYLOAD;
return 0;
}
static inline void virtblk_request_done(struct request *req)
{
struct virtblk_req *vbr = blk_mq_rq_to_pdu(req);
if (req->rq_flags & RQF_SPECIAL_PAYLOAD) {
kfree(page_address(req->special_vec.bv_page) +
req->special_vec.bv_offset);
}
blk_mq_end_request(req, virtblk_result(vbr));
}
static void virtblk_done(struct virtqueue *vq)
{
struct virtio_blk *vblk = vq->vdev->priv;
bool req_done = false;
int qid = vq->index;
struct virtblk_req *vbr;
unsigned long flags;
unsigned int len;
spin_lock_irqsave(&vblk->vqs[qid].lock, flags);
do {
virtqueue_disable_cb(vq);
while ((vbr = virtqueue_get_buf(vblk->vqs[qid].vq, &len)) != NULL) {
struct request *req = blk_mq_rq_from_pdu(vbr);
if (likely(!blk_should_fake_timeout(req->q)))
blk_mq_complete_request(req);
req_done = true;
}
if (unlikely(virtqueue_is_broken(vq)))
break;
} while (!virtqueue_enable_cb(vq));
/* In case queue is stopped waiting for more buffers. */
if (req_done)
blk_mq_start_stopped_hw_queues(vblk->disk->queue, true);
spin_unlock_irqrestore(&vblk->vqs[qid].lock, flags);
}
static void virtio_commit_rqs(struct blk_mq_hw_ctx *hctx)
{
struct virtio_blk *vblk = hctx->queue->queuedata;
struct virtio_blk_vq *vq = &vblk->vqs[hctx->queue_num];
bool kick;
spin_lock_irq(&vq->lock);
kick = virtqueue_kick_prepare(vq->vq);
spin_unlock_irq(&vq->lock);
if (kick)
virtqueue_notify(vq->vq);
}
static blk_status_t virtio_queue_rq(struct blk_mq_hw_ctx *hctx,
const struct blk_mq_queue_data *bd)
{
struct virtio_blk *vblk = hctx->queue->queuedata;
struct request *req = bd->rq;
struct virtblk_req *vbr = blk_mq_rq_to_pdu(req);
unsigned long flags;
unsigned int num;
int qid = hctx->queue_num;
int err;
bool notify = false;
bool unmap = false;
u32 type;
BUG_ON(req->nr_phys_segments + 2 > vblk->sg_elems);
switch (req_op(req)) {
case REQ_OP_READ:
case REQ_OP_WRITE:
type = 0;
break;
case REQ_OP_FLUSH:
type = VIRTIO_BLK_T_FLUSH;
break;
case REQ_OP_DISCARD:
type = VIRTIO_BLK_T_DISCARD;
break;
case REQ_OP_WRITE_ZEROES:
type = VIRTIO_BLK_T_WRITE_ZEROES;
unmap = !(req->cmd_flags & REQ_NOUNMAP);
break;
case REQ_OP_DRV_IN:
type = VIRTIO_BLK_T_GET_ID;
break;
default:
WARN_ON_ONCE(1);
return BLK_STS_IOERR;
}
vbr->out_hdr.type = cpu_to_virtio32(vblk->vdev, type);
vbr->out_hdr.sector = type ?
0 : cpu_to_virtio64(vblk->vdev, blk_rq_pos(req));
vbr->out_hdr.ioprio = cpu_to_virtio32(vblk->vdev, req_get_ioprio(req));
blk_mq_start_request(req);
if (type == VIRTIO_BLK_T_DISCARD || type == VIRTIO_BLK_T_WRITE_ZEROES) {
err = virtblk_setup_discard_write_zeroes(req, unmap);
if (err)
return BLK_STS_RESOURCE;
}
num = blk_rq_map_sg(hctx->queue, req, vbr->sg);
if (num) {
if (rq_data_dir(req) == WRITE)
vbr->out_hdr.type |= cpu_to_virtio32(vblk->vdev, VIRTIO_BLK_T_OUT);
else
vbr->out_hdr.type |= cpu_to_virtio32(vblk->vdev, VIRTIO_BLK_T_IN);
}
spin_lock_irqsave(&vblk->vqs[qid].lock, flags);
err = virtblk_add_req(vblk->vqs[qid].vq, vbr, vbr->sg, num);
if (err) {
virtqueue_kick(vblk->vqs[qid].vq);
/* Don't stop the queue if -ENOMEM: we may have failed to
* bounce the buffer due to global resource outage.
*/
if (err == -ENOSPC)
blk_mq_stop_hw_queue(hctx);
spin_unlock_irqrestore(&vblk->vqs[qid].lock, flags);
switch (err) {
case -ENOSPC:
return BLK_STS_DEV_RESOURCE;
case -ENOMEM:
return BLK_STS_RESOURCE;
default:
return BLK_STS_IOERR;
}
}
if (bd->last && virtqueue_kick_prepare(vblk->vqs[qid].vq))
notify = true;
spin_unlock_irqrestore(&vblk->vqs[qid].lock, flags);
if (notify)
virtqueue_notify(vblk->vqs[qid].vq);
return BLK_STS_OK;
}
/* return id (s/n) string for *disk to *id_str
*/
static int virtblk_get_id(struct gendisk *disk, char *id_str)
{
struct virtio_blk *vblk = disk->private_data;
struct request_queue *q = vblk->disk->queue;
struct request *req;
int err;
req = blk_get_request(q, REQ_OP_DRV_IN, 0);
if (IS_ERR(req))
return PTR_ERR(req);
err = blk_rq_map_kern(q, req, id_str, VIRTIO_BLK_ID_BYTES, GFP_KERNEL);
if (err)
goto out;
blk_execute_rq(vblk->disk, req, false);
err = blk_status_to_errno(virtblk_result(blk_mq_rq_to_pdu(req)));
out:
blk_put_request(req);
return err;
}
static void virtblk_get(struct virtio_blk *vblk)
{
refcount_inc(&vblk->refs);
}
static void virtblk_put(struct virtio_blk *vblk)
{
if (refcount_dec_and_test(&vblk->refs)) {
ida_simple_remove(&vd_index_ida, vblk->index);
mutex_destroy(&vblk->vdev_mutex);
kfree(vblk);
}
}
static int virtblk_open(struct block_device *bd, fmode_t mode)
{
struct virtio_blk *vblk = bd->bd_disk->private_data;
int ret = 0;
mutex_lock(&vblk->vdev_mutex);
if (vblk->vdev)
virtblk_get(vblk);
else
ret = -ENXIO;
mutex_unlock(&vblk->vdev_mutex);
return ret;
}
static void virtblk_release(struct gendisk *disk, fmode_t mode)
{
struct virtio_blk *vblk = disk->private_data;
virtblk_put(vblk);
}
/* We provide getgeo only to please some old bootloader/partitioning tools */
static int virtblk_getgeo(struct block_device *bd, struct hd_geometry *geo)
{
struct virtio_blk *vblk = bd->bd_disk->private_data;
int ret = 0;
mutex_lock(&vblk->vdev_mutex);
if (!vblk->vdev) {
ret = -ENXIO;
goto out;
}
/* see if the host passed in geometry config */
if (virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_GEOMETRY)) {
virtio_cread(vblk->vdev, struct virtio_blk_config,
geometry.cylinders, &geo->cylinders);
virtio_cread(vblk->vdev, struct virtio_blk_config,
geometry.heads, &geo->heads);
virtio_cread(vblk->vdev, struct virtio_blk_config,
geometry.sectors, &geo->sectors);
} else {
/* some standard values, similar to sd */
geo->heads = 1 << 6;
geo->sectors = 1 << 5;
geo->cylinders = get_capacity(bd->bd_disk) >> 11;
}
out:
mutex_unlock(&vblk->vdev_mutex);
return ret;
}
static const struct block_device_operations virtblk_fops = {
.owner = THIS_MODULE,
.open = virtblk_open,
.release = virtblk_release,
.getgeo = virtblk_getgeo,
};
static int index_to_minor(int index)
{
return index << PART_BITS;
}
static int minor_to_index(int minor)
{
return minor >> PART_BITS;
}
static ssize_t serial_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct gendisk *disk = dev_to_disk(dev);
int err;
/* sysfs gives us a PAGE_SIZE buffer */
BUILD_BUG_ON(PAGE_SIZE < VIRTIO_BLK_ID_BYTES);
buf[VIRTIO_BLK_ID_BYTES] = '\0';
err = virtblk_get_id(disk, buf);
if (!err)
return strlen(buf);
if (err == -EIO) /* Unsupported? Make it empty. */
return 0;
return err;
}
static DEVICE_ATTR_RO(serial);
/* The queue's logical block size must be set before calling this */
static void virtblk_update_capacity(struct virtio_blk *vblk, bool resize)
{
struct virtio_device *vdev = vblk->vdev;
struct request_queue *q = vblk->disk->queue;
char cap_str_2[10], cap_str_10[10];
unsigned long long nblocks;
u64 capacity;
/* Host must always specify the capacity. */
virtio_cread(vdev, struct virtio_blk_config, capacity, &capacity);
nblocks = DIV_ROUND_UP_ULL(capacity, queue_logical_block_size(q) >> 9);
string_get_size(nblocks, queue_logical_block_size(q),
STRING_UNITS_2, cap_str_2, sizeof(cap_str_2));
string_get_size(nblocks, queue_logical_block_size(q),
STRING_UNITS_10, cap_str_10, sizeof(cap_str_10));
dev_notice(&vdev->dev,
"[%s] %s%llu %d-byte logical blocks (%s/%s)\n",
vblk->disk->disk_name,
resize ? "new size: " : "",
nblocks,
queue_logical_block_size(q),
cap_str_10,
cap_str_2);
set_capacity_and_notify(vblk->disk, capacity);
}
static void virtblk_config_changed_work(struct work_struct *work)
{
struct virtio_blk *vblk =
container_of(work, struct virtio_blk, config_work);
virtblk_update_capacity(vblk, true);
}
static void virtblk_config_changed(struct virtio_device *vdev)
{
struct virtio_blk *vblk = vdev->priv;
queue_work(virtblk_wq, &vblk->config_work);
}
static int init_vq(struct virtio_blk *vblk)
{
int err;
int i;
vq_callback_t **callbacks;
const char **names;
struct virtqueue **vqs;
unsigned short num_vqs;
struct virtio_device *vdev = vblk->vdev;
struct irq_affinity desc = { 0, };
err = virtio_cread_feature(vdev, VIRTIO_BLK_F_MQ,
struct virtio_blk_config, num_queues,
&num_vqs);
if (err)
num_vqs = 1;
num_vqs = min_t(unsigned int, nr_cpu_ids, num_vqs);
vblk->vqs = kmalloc_array(num_vqs, sizeof(*vblk->vqs), GFP_KERNEL);
if (!vblk->vqs)
return -ENOMEM;
names = kmalloc_array(num_vqs, sizeof(*names), GFP_KERNEL);
callbacks = kmalloc_array(num_vqs, sizeof(*callbacks), GFP_KERNEL);
vqs = kmalloc_array(num_vqs, sizeof(*vqs), GFP_KERNEL);
if (!names || !callbacks || !vqs) {
err = -ENOMEM;
goto out;
}
for (i = 0; i < num_vqs; i++) {
callbacks[i] = virtblk_done;
snprintf(vblk->vqs[i].name, VQ_NAME_LEN, "req.%d", i);
names[i] = vblk->vqs[i].name;
}
/* Discover virtqueues and write information to configuration. */
err = virtio_find_vqs(vdev, num_vqs, vqs, callbacks, names, &desc);
if (err)
goto out;
for (i = 0; i < num_vqs; i++) {
spin_lock_init(&vblk->vqs[i].lock);
vblk->vqs[i].vq = vqs[i];
}
vblk->num_vqs = num_vqs;
out:
kfree(vqs);
kfree(callbacks);
kfree(names);
if (err)
kfree(vblk->vqs);
return err;
}
/*
* Legacy naming scheme used for virtio devices. We are stuck with it for
* virtio blk but don't ever use it for any new driver.
*/
static int virtblk_name_format(char *prefix, int index, char *buf, int buflen)
{
const int base = 'z' - 'a' + 1;
char *begin = buf + strlen(prefix);
char *end = buf + buflen;
char *p;
int unit;
p = end - 1;
*p = '\0';
unit = base;
do {
if (p == begin)
return -EINVAL;
*--p = 'a' + (index % unit);
index = (index / unit) - 1;
} while (index >= 0);
memmove(begin, p, end - p);
memcpy(buf, prefix, strlen(prefix));
return 0;
}
static int virtblk_get_cache_mode(struct virtio_device *vdev)
{
u8 writeback;
int err;
err = virtio_cread_feature(vdev, VIRTIO_BLK_F_CONFIG_WCE,
struct virtio_blk_config, wce,
&writeback);
/*
* If WCE is not configurable and flush is not available,
* assume no writeback cache is in use.
*/
if (err)
writeback = virtio_has_feature(vdev, VIRTIO_BLK_F_FLUSH);
return writeback;
}
static void virtblk_update_cache_mode(struct virtio_device *vdev)
{
u8 writeback = virtblk_get_cache_mode(vdev);
struct virtio_blk *vblk = vdev->priv;
blk_queue_write_cache(vblk->disk->queue, writeback, false);
}
static const char *const virtblk_cache_types[] = {
"write through", "write back"
};
static ssize_t
cache_type_store(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
struct gendisk *disk = dev_to_disk(dev);
struct virtio_blk *vblk = disk->private_data;
struct virtio_device *vdev = vblk->vdev;
int i;
BUG_ON(!virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_CONFIG_WCE));
i = sysfs_match_string(virtblk_cache_types, buf);
if (i < 0)
return i;
virtio_cwrite8(vdev, offsetof(struct virtio_blk_config, wce), i);
virtblk_update_cache_mode(vdev);
return count;
}
static ssize_t
cache_type_show(struct device *dev, struct device_attribute *attr, char *buf)
{
struct gendisk *disk = dev_to_disk(dev);
struct virtio_blk *vblk = disk->private_data;
u8 writeback = virtblk_get_cache_mode(vblk->vdev);
BUG_ON(writeback >= ARRAY_SIZE(virtblk_cache_types));
return snprintf(buf, 40, "%s\n", virtblk_cache_types[writeback]);
}
static DEVICE_ATTR_RW(cache_type);
static struct attribute *virtblk_attrs[] = {
&dev_attr_serial.attr,
&dev_attr_cache_type.attr,
NULL,
};
static umode_t virtblk_attrs_are_visible(struct kobject *kobj,
struct attribute *a, int n)
{
struct device *dev = kobj_to_dev(kobj);
struct gendisk *disk = dev_to_disk(dev);
struct virtio_blk *vblk = disk->private_data;
struct virtio_device *vdev = vblk->vdev;
if (a == &dev_attr_cache_type.attr &&
!virtio_has_feature(vdev, VIRTIO_BLK_F_CONFIG_WCE))
return S_IRUGO;
return a->mode;
}
static const struct attribute_group virtblk_attr_group = {
.attrs = virtblk_attrs,
.is_visible = virtblk_attrs_are_visible,
};
static const struct attribute_group *virtblk_attr_groups[] = {
&virtblk_attr_group,
NULL,
};
static int virtblk_init_request(struct blk_mq_tag_set *set, struct request *rq,
unsigned int hctx_idx, unsigned int numa_node)
{
struct virtio_blk *vblk = set->driver_data;
struct virtblk_req *vbr = blk_mq_rq_to_pdu(rq);
sg_init_table(vbr->sg, vblk->sg_elems);
return 0;
}
static int virtblk_map_queues(struct blk_mq_tag_set *set)
{
struct virtio_blk *vblk = set->driver_data;
return blk_mq_virtio_map_queues(&set->map[HCTX_TYPE_DEFAULT],
vblk->vdev, 0);
}
static const struct blk_mq_ops virtio_mq_ops = {
.queue_rq = virtio_queue_rq,
.commit_rqs = virtio_commit_rqs,
.complete = virtblk_request_done,
.init_request = virtblk_init_request,
.map_queues = virtblk_map_queues,
};
static unsigned int virtblk_queue_depth;
module_param_named(queue_depth, virtblk_queue_depth, uint, 0444);
static int virtblk_validate(struct virtio_device *vdev)
{
u32 blk_size;
if (!vdev->config->get) {
dev_err(&vdev->dev, "%s failure: config access disabled\n",
__func__);
return -EINVAL;
}
if (!virtio_has_feature(vdev, VIRTIO_BLK_F_BLK_SIZE))
return 0;
blk_size = virtio_cread32(vdev,
offsetof(struct virtio_blk_config, blk_size));
if (blk_size < SECTOR_SIZE || blk_size > PAGE_SIZE)
__virtio_clear_bit(vdev, VIRTIO_BLK_F_BLK_SIZE);
return 0;
}
static int virtblk_probe(struct virtio_device *vdev)
{
struct virtio_blk *vblk;
struct request_queue *q;
int err, index;
u32 v, blk_size, max_size, sg_elems, opt_io_size;
u16 min_io_size;
u8 physical_block_exp, alignment_offset;
unsigned int queue_depth;
err = ida_simple_get(&vd_index_ida, 0, minor_to_index(1 << MINORBITS),
GFP_KERNEL);
if (err < 0)
goto out;
index = err;
/* We need to know how many segments before we allocate. */
err = virtio_cread_feature(vdev, VIRTIO_BLK_F_SEG_MAX,
struct virtio_blk_config, seg_max,
&sg_elems);
/* We need at least one SG element, whatever they say. */
if (err || !sg_elems)
sg_elems = 1;
/* Prevent integer overflows and honor max vq size */
sg_elems = min_t(u32, sg_elems, VIRTIO_BLK_MAX_SG_ELEMS - 2);
/* We need extra sg elements at head and tail. */
sg_elems += 2;
vdev->priv = vblk = kmalloc(sizeof(*vblk), GFP_KERNEL);
if (!vblk) {
err = -ENOMEM;
goto out_free_index;
}
/* This reference is dropped in virtblk_remove(). */
refcount_set(&vblk->refs, 1);
mutex_init(&vblk->vdev_mutex);
vblk->vdev = vdev;
vblk->sg_elems = sg_elems;
INIT_WORK(&vblk->config_work, virtblk_config_changed_work);
err = init_vq(vblk);
if (err)
goto out_free_vblk;
/* Default queue sizing is to fill the ring. */
if (likely(!virtblk_queue_depth)) {
queue_depth = vblk->vqs[0].vq->num_free;
/* ... but without indirect descs, we use 2 descs per req */
if (!virtio_has_feature(vdev, VIRTIO_RING_F_INDIRECT_DESC))
queue_depth /= 2;
} else {
queue_depth = virtblk_queue_depth;
}
memset(&vblk->tag_set, 0, sizeof(vblk->tag_set));
vblk->tag_set.ops = &virtio_mq_ops;
vblk->tag_set.queue_depth = queue_depth;
vblk->tag_set.numa_node = NUMA_NO_NODE;
vblk->tag_set.flags = BLK_MQ_F_SHOULD_MERGE;
vblk->tag_set.cmd_size =
sizeof(struct virtblk_req) +
sizeof(struct scatterlist) * sg_elems;
vblk->tag_set.driver_data = vblk;
vblk->tag_set.nr_hw_queues = vblk->num_vqs;
err = blk_mq_alloc_tag_set(&vblk->tag_set);
if (err)
goto out_free_vq;
vblk->disk = blk_mq_alloc_disk(&vblk->tag_set, vblk);
if (IS_ERR(vblk->disk)) {
err = PTR_ERR(vblk->disk);
goto out_free_tags;
}
q = vblk->disk->queue;
virtblk_name_format("vd", index, vblk->disk->disk_name, DISK_NAME_LEN);
vblk->disk->major = major;
vblk->disk->first_minor = index_to_minor(index);
vblk->disk->minors = 1 << PART_BITS;
vblk->disk->private_data = vblk;
vblk->disk->fops = &virtblk_fops;
vblk->disk->flags |= GENHD_FL_EXT_DEVT;
vblk->index = index;
/* configure queue flush support */
virtblk_update_cache_mode(vdev);
/* If disk is read-only in the host, the guest should obey */
if (virtio_has_feature(vdev, VIRTIO_BLK_F_RO))
set_disk_ro(vblk->disk, 1);
/* We can handle whatever the host told us to handle. */
blk_queue_max_segments(q, vblk->sg_elems-2);
/* No real sector limit. */
blk_queue_max_hw_sectors(q, -1U);
max_size = virtio_max_dma_size(vdev);
/* Host can optionally specify maximum segment size and number of
* segments. */
err = virtio_cread_feature(vdev, VIRTIO_BLK_F_SIZE_MAX,
struct virtio_blk_config, size_max, &v);
if (!err)
max_size = min(max_size, v);
blk_queue_max_segment_size(q, max_size);
/* Host can optionally specify the block size of the device */
err = virtio_cread_feature(vdev, VIRTIO_BLK_F_BLK_SIZE,
struct virtio_blk_config, blk_size,
&blk_size);
if (!err)
blk_queue_logical_block_size(q, blk_size);
else
blk_size = queue_logical_block_size(q);
if (unlikely(blk_size < SECTOR_SIZE || blk_size > PAGE_SIZE)) {
dev_err(&vdev->dev,
"block size is changed unexpectedly, now is %u\n",
blk_size);
err = -EINVAL;
goto err_cleanup_disk;
}
/* Use topology information if available */
err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY,
struct virtio_blk_config, physical_block_exp,
&physical_block_exp);
if (!err && physical_block_exp)
blk_queue_physical_block_size(q,
blk_size * (1 << physical_block_exp));
err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY,
struct virtio_blk_config, alignment_offset,
&alignment_offset);
if (!err && alignment_offset)
blk_queue_alignment_offset(q, blk_size * alignment_offset);
err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY,
struct virtio_blk_config, min_io_size,
&min_io_size);
if (!err && min_io_size)
blk_queue_io_min(q, blk_size * min_io_size);
err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY,
struct virtio_blk_config, opt_io_size,
&opt_io_size);
if (!err && opt_io_size)
blk_queue_io_opt(q, blk_size * opt_io_size);
if (virtio_has_feature(vdev, VIRTIO_BLK_F_DISCARD)) {
q->limits.discard_granularity = blk_size;
virtio_cread(vdev, struct virtio_blk_config,
discard_sector_alignment, &v);
q->limits.discard_alignment = v ? v << SECTOR_SHIFT : 0;
virtio_cread(vdev, struct virtio_blk_config,
max_discard_sectors, &v);
blk_queue_max_discard_sectors(q, v ? v : UINT_MAX);
virtio_cread(vdev, struct virtio_blk_config, max_discard_seg,
&v);
blk_queue_max_discard_segments(q,
min_not_zero(v,
MAX_DISCARD_SEGMENTS));
blk_queue_flag_set(QUEUE_FLAG_DISCARD, q);
}
if (virtio_has_feature(vdev, VIRTIO_BLK_F_WRITE_ZEROES)) {
virtio_cread(vdev, struct virtio_blk_config,
max_write_zeroes_sectors, &v);
blk_queue_max_write_zeroes_sectors(q, v ? v : UINT_MAX);
}
virtblk_update_capacity(vblk, false);
virtio_device_ready(vdev);
device_add_disk(&vdev->dev, vblk->disk, virtblk_attr_groups);
return 0;
err_cleanup_disk:
blk_cleanup_disk(vblk->disk);
out_free_tags:
blk_mq_free_tag_set(&vblk->tag_set);
out_free_vq:
vdev->config->del_vqs(vdev);
kfree(vblk->vqs);
out_free_vblk:
kfree(vblk);
out_free_index:
ida_simple_remove(&vd_index_ida, index);
out:
return err;
}
static void virtblk_remove(struct virtio_device *vdev)
{
struct virtio_blk *vblk = vdev->priv;
/* Make sure no work handler is accessing the device. */
flush_work(&vblk->config_work);
del_gendisk(vblk->disk);
blk_cleanup_disk(vblk->disk);
blk_mq_free_tag_set(&vblk->tag_set);
mutex_lock(&vblk->vdev_mutex);
/* Stop all the virtqueues. */
vdev->config->reset(vdev);
/* Virtqueues are stopped, nothing can use vblk->vdev anymore. */
vblk->vdev = NULL;
vdev->config->del_vqs(vdev);
kfree(vblk->vqs);
mutex_unlock(&vblk->vdev_mutex);
virtblk_put(vblk);
}
#ifdef CONFIG_PM_SLEEP
static int virtblk_freeze(struct virtio_device *vdev)
{
struct virtio_blk *vblk = vdev->priv;
/* Ensure we don't receive any more interrupts */
vdev->config->reset(vdev);
/* Make sure no work handler is accessing the device. */
flush_work(&vblk->config_work);
blk_mq_quiesce_queue(vblk->disk->queue);
vdev->config->del_vqs(vdev);
kfree(vblk->vqs);
return 0;
}
static int virtblk_restore(struct virtio_device *vdev)
{
struct virtio_blk *vblk = vdev->priv;
int ret;
ret = init_vq(vdev->priv);
if (ret)
return ret;
virtio_device_ready(vdev);
blk_mq_unquiesce_queue(vblk->disk->queue);
return 0;
}
#endif
static const struct virtio_device_id id_table[] = {
{ VIRTIO_ID_BLOCK, VIRTIO_DEV_ANY_ID },
{ 0 },
};
static unsigned int features_legacy[] = {
VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX, VIRTIO_BLK_F_GEOMETRY,
VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE,
VIRTIO_BLK_F_FLUSH, VIRTIO_BLK_F_TOPOLOGY, VIRTIO_BLK_F_CONFIG_WCE,
VIRTIO_BLK_F_MQ, VIRTIO_BLK_F_DISCARD, VIRTIO_BLK_F_WRITE_ZEROES,
}
;
static unsigned int features[] = {
VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX, VIRTIO_BLK_F_GEOMETRY,
VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE,
VIRTIO_BLK_F_FLUSH, VIRTIO_BLK_F_TOPOLOGY, VIRTIO_BLK_F_CONFIG_WCE,
VIRTIO_BLK_F_MQ, VIRTIO_BLK_F_DISCARD, VIRTIO_BLK_F_WRITE_ZEROES,
};
static struct virtio_driver virtio_blk = {
.feature_table = features,
.feature_table_size = ARRAY_SIZE(features),
.feature_table_legacy = features_legacy,
.feature_table_size_legacy = ARRAY_SIZE(features_legacy),
.driver.name = KBUILD_MODNAME,
.driver.owner = THIS_MODULE,
.id_table = id_table,
.validate = virtblk_validate,
.probe = virtblk_probe,
.remove = virtblk_remove,
.config_changed = virtblk_config_changed,
#ifdef CONFIG_PM_SLEEP
.freeze = virtblk_freeze,
.restore = virtblk_restore,
#endif
};
static int __init init(void)
{
int error;
virtblk_wq = alloc_workqueue("virtio-blk", 0, 0);
if (!virtblk_wq)
return -ENOMEM;
major = register_blkdev(0, "virtblk");
if (major < 0) {
error = major;
goto out_destroy_workqueue;
}
error = register_virtio_driver(&virtio_blk);
if (error)
goto out_unregister_blkdev;
return 0;
out_unregister_blkdev:
unregister_blkdev(major, "virtblk");
out_destroy_workqueue:
destroy_workqueue(virtblk_wq);
return error;
}
static void __exit fini(void)
{
unregister_virtio_driver(&virtio_blk);
unregister_blkdev(major, "virtblk");
destroy_workqueue(virtblk_wq);
}
module_init(init);
module_exit(fini);
MODULE_DEVICE_TABLE(virtio, id_table);
MODULE_DESCRIPTION("Virtio block driver");
MODULE_LICENSE("GPL");