blob: a790903f243e8dd5d10101d7bc32b3a82a1709a0 [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0-only
/*
* VDPA simulator for block device.
*
* Copyright (c) 2020, NVIDIA CORPORATION. All rights reserved.
* Copyright (c) 2021, Red Hat Inc. All rights reserved.
*
*/
#include <linux/init.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/blkdev.h>
#include <linux/vringh.h>
#include <linux/vdpa.h>
#include <uapi/linux/virtio_blk.h>
#include "vdpa_sim.h"
#define DRV_VERSION "0.1"
#define DRV_AUTHOR "Max Gurtovoy <mgurtovoy@nvidia.com>"
#define DRV_DESC "vDPA Device Simulator for block device"
#define DRV_LICENSE "GPL v2"
#define VDPASIM_BLK_FEATURES (VDPASIM_FEATURES | \
(1ULL << VIRTIO_BLK_F_SIZE_MAX) | \
(1ULL << VIRTIO_BLK_F_SEG_MAX) | \
(1ULL << VIRTIO_BLK_F_BLK_SIZE) | \
(1ULL << VIRTIO_BLK_F_TOPOLOGY) | \
(1ULL << VIRTIO_BLK_F_MQ))
#define VDPASIM_BLK_CAPACITY 0x40000
#define VDPASIM_BLK_SIZE_MAX 0x1000
#define VDPASIM_BLK_SEG_MAX 32
#define VDPASIM_BLK_VQ_NUM 1
static char vdpasim_blk_id[VIRTIO_BLK_ID_BYTES] = "vdpa_blk_sim";
static bool vdpasim_blk_check_range(u64 start_sector, size_t range_size)
{
u64 range_sectors = range_size >> SECTOR_SHIFT;
if (range_size > VDPASIM_BLK_SIZE_MAX * VDPASIM_BLK_SEG_MAX)
return false;
if (start_sector > VDPASIM_BLK_CAPACITY)
return false;
if (range_sectors > VDPASIM_BLK_CAPACITY - start_sector)
return false;
return true;
}
/* Returns 'true' if the request is handled (with or without an I/O error)
* and the status is correctly written in the last byte of the 'in iov',
* 'false' otherwise.
*/
static bool vdpasim_blk_handle_req(struct vdpasim *vdpasim,
struct vdpasim_virtqueue *vq)
{
size_t pushed = 0, to_pull, to_push;
struct virtio_blk_outhdr hdr;
ssize_t bytes;
loff_t offset;
u64 sector;
u8 status;
u32 type;
int ret;
ret = vringh_getdesc_iotlb(&vq->vring, &vq->out_iov, &vq->in_iov,
&vq->head, GFP_ATOMIC);
if (ret != 1)
return false;
if (vq->out_iov.used < 1 || vq->in_iov.used < 1) {
dev_err(&vdpasim->vdpa.dev, "missing headers - out_iov: %u in_iov %u\n",
vq->out_iov.used, vq->in_iov.used);
return false;
}
if (vq->in_iov.iov[vq->in_iov.used - 1].iov_len < 1) {
dev_err(&vdpasim->vdpa.dev, "request in header too short\n");
return false;
}
/* The last byte is the status and we checked if the last iov has
* enough room for it.
*/
to_push = vringh_kiov_length(&vq->in_iov) - 1;
to_pull = vringh_kiov_length(&vq->out_iov);
bytes = vringh_iov_pull_iotlb(&vq->vring, &vq->out_iov, &hdr,
sizeof(hdr));
if (bytes != sizeof(hdr)) {
dev_err(&vdpasim->vdpa.dev, "request out header too short\n");
return false;
}
to_pull -= bytes;
type = vdpasim32_to_cpu(vdpasim, hdr.type);
sector = vdpasim64_to_cpu(vdpasim, hdr.sector);
offset = sector << SECTOR_SHIFT;
status = VIRTIO_BLK_S_OK;
switch (type) {
case VIRTIO_BLK_T_IN:
if (!vdpasim_blk_check_range(sector, to_push)) {
dev_err(&vdpasim->vdpa.dev,
"reading over the capacity - offset: 0x%llx len: 0x%zx\n",
offset, to_push);
status = VIRTIO_BLK_S_IOERR;
break;
}
bytes = vringh_iov_push_iotlb(&vq->vring, &vq->in_iov,
vdpasim->buffer + offset,
to_push);
if (bytes < 0) {
dev_err(&vdpasim->vdpa.dev,
"vringh_iov_push_iotlb() error: %zd offset: 0x%llx len: 0x%zx\n",
bytes, offset, to_push);
status = VIRTIO_BLK_S_IOERR;
break;
}
pushed += bytes;
break;
case VIRTIO_BLK_T_OUT:
if (!vdpasim_blk_check_range(sector, to_pull)) {
dev_err(&vdpasim->vdpa.dev,
"writing over the capacity - offset: 0x%llx len: 0x%zx\n",
offset, to_pull);
status = VIRTIO_BLK_S_IOERR;
break;
}
bytes = vringh_iov_pull_iotlb(&vq->vring, &vq->out_iov,
vdpasim->buffer + offset,
to_pull);
if (bytes < 0) {
dev_err(&vdpasim->vdpa.dev,
"vringh_iov_pull_iotlb() error: %zd offset: 0x%llx len: 0x%zx\n",
bytes, offset, to_pull);
status = VIRTIO_BLK_S_IOERR;
break;
}
break;
case VIRTIO_BLK_T_GET_ID:
bytes = vringh_iov_push_iotlb(&vq->vring, &vq->in_iov,
vdpasim_blk_id,
VIRTIO_BLK_ID_BYTES);
if (bytes < 0) {
dev_err(&vdpasim->vdpa.dev,
"vringh_iov_push_iotlb() error: %zd\n", bytes);
status = VIRTIO_BLK_S_IOERR;
break;
}
pushed += bytes;
break;
default:
dev_warn(&vdpasim->vdpa.dev,
"Unsupported request type %d\n", type);
status = VIRTIO_BLK_S_IOERR;
break;
}
/* If some operations fail, we need to skip the remaining bytes
* to put the status in the last byte
*/
if (to_push - pushed > 0)
vringh_kiov_advance(&vq->in_iov, to_push - pushed);
/* Last byte is the status */
bytes = vringh_iov_push_iotlb(&vq->vring, &vq->in_iov, &status, 1);
if (bytes != 1)
return false;
pushed += bytes;
/* Make sure data is wrote before advancing index */
smp_wmb();
vringh_complete_iotlb(&vq->vring, vq->head, pushed);
return true;
}
static void vdpasim_blk_work(struct work_struct *work)
{
struct vdpasim *vdpasim = container_of(work, struct vdpasim, work);
int i;
spin_lock(&vdpasim->lock);
if (!(vdpasim->status & VIRTIO_CONFIG_S_DRIVER_OK))
goto out;
for (i = 0; i < VDPASIM_BLK_VQ_NUM; i++) {
struct vdpasim_virtqueue *vq = &vdpasim->vqs[i];
if (!vq->ready)
continue;
while (vdpasim_blk_handle_req(vdpasim, vq)) {
/* Make sure used is visible before rasing the interrupt. */
smp_wmb();
local_bh_disable();
if (vringh_need_notify_iotlb(&vq->vring) > 0)
vringh_notify(&vq->vring);
local_bh_enable();
}
}
out:
spin_unlock(&vdpasim->lock);
}
static void vdpasim_blk_get_config(struct vdpasim *vdpasim, void *config)
{
struct virtio_blk_config *blk_config = config;
memset(config, 0, sizeof(struct virtio_blk_config));
blk_config->capacity = cpu_to_vdpasim64(vdpasim, VDPASIM_BLK_CAPACITY);
blk_config->size_max = cpu_to_vdpasim32(vdpasim, VDPASIM_BLK_SIZE_MAX);
blk_config->seg_max = cpu_to_vdpasim32(vdpasim, VDPASIM_BLK_SEG_MAX);
blk_config->num_queues = cpu_to_vdpasim16(vdpasim, VDPASIM_BLK_VQ_NUM);
blk_config->min_io_size = cpu_to_vdpasim16(vdpasim, 1);
blk_config->opt_io_size = cpu_to_vdpasim32(vdpasim, 1);
blk_config->blk_size = cpu_to_vdpasim32(vdpasim, SECTOR_SIZE);
}
static void vdpasim_blk_mgmtdev_release(struct device *dev)
{
}
static struct device vdpasim_blk_mgmtdev = {
.init_name = "vdpasim_blk",
.release = vdpasim_blk_mgmtdev_release,
};
static int vdpasim_blk_dev_add(struct vdpa_mgmt_dev *mdev, const char *name)
{
struct vdpasim_dev_attr dev_attr = {};
struct vdpasim *simdev;
int ret;
dev_attr.mgmt_dev = mdev;
dev_attr.name = name;
dev_attr.id = VIRTIO_ID_BLOCK;
dev_attr.supported_features = VDPASIM_BLK_FEATURES;
dev_attr.nvqs = VDPASIM_BLK_VQ_NUM;
dev_attr.config_size = sizeof(struct virtio_blk_config);
dev_attr.get_config = vdpasim_blk_get_config;
dev_attr.work_fn = vdpasim_blk_work;
dev_attr.buffer_size = VDPASIM_BLK_CAPACITY << SECTOR_SHIFT;
simdev = vdpasim_create(&dev_attr);
if (IS_ERR(simdev))
return PTR_ERR(simdev);
ret = _vdpa_register_device(&simdev->vdpa, VDPASIM_BLK_VQ_NUM);
if (ret)
goto put_dev;
return 0;
put_dev:
put_device(&simdev->vdpa.dev);
return ret;
}
static void vdpasim_blk_dev_del(struct vdpa_mgmt_dev *mdev,
struct vdpa_device *dev)
{
struct vdpasim *simdev = container_of(dev, struct vdpasim, vdpa);
_vdpa_unregister_device(&simdev->vdpa);
}
static const struct vdpa_mgmtdev_ops vdpasim_blk_mgmtdev_ops = {
.dev_add = vdpasim_blk_dev_add,
.dev_del = vdpasim_blk_dev_del
};
static struct virtio_device_id id_table[] = {
{ VIRTIO_ID_BLOCK, VIRTIO_DEV_ANY_ID },
{ 0 },
};
static struct vdpa_mgmt_dev mgmt_dev = {
.device = &vdpasim_blk_mgmtdev,
.id_table = id_table,
.ops = &vdpasim_blk_mgmtdev_ops,
};
static int __init vdpasim_blk_init(void)
{
int ret;
ret = device_register(&vdpasim_blk_mgmtdev);
if (ret)
return ret;
ret = vdpa_mgmtdev_register(&mgmt_dev);
if (ret)
goto parent_err;
return 0;
parent_err:
device_unregister(&vdpasim_blk_mgmtdev);
return ret;
}
static void __exit vdpasim_blk_exit(void)
{
vdpa_mgmtdev_unregister(&mgmt_dev);
device_unregister(&vdpasim_blk_mgmtdev);
}
module_init(vdpasim_blk_init)
module_exit(vdpasim_blk_exit)
MODULE_VERSION(DRV_VERSION);
MODULE_LICENSE(DRV_LICENSE);
MODULE_AUTHOR(DRV_AUTHOR);
MODULE_DESCRIPTION(DRV_DESC);