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path: root/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c
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Diffstat (limited to 'drivers/vdpa/vdpa_sim/vdpa_sim_blk.c')
-rw-r--r--drivers/vdpa/vdpa_sim/vdpa_sim_blk.c458
1 files changed, 458 insertions, 0 deletions
diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c b/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c
new file mode 100644
index 000000000..f74592623
--- /dev/null
+++ b/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c
@@ -0,0 +1,458 @@
+// 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_FLUSH) | \
+ (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) | \
+ (1ULL << VIRTIO_BLK_F_DISCARD) | \
+ (1ULL << VIRTIO_BLK_F_WRITE_ZEROES))
+
+#define VDPASIM_BLK_CAPACITY 0x40000
+#define VDPASIM_BLK_SIZE_MAX 0x1000
+#define VDPASIM_BLK_SEG_MAX 32
+#define VDPASIM_BLK_DWZ_MAX_SECTORS UINT_MAX
+
+/* 1 virtqueue, 1 address space, 1 virtqueue group */
+#define VDPASIM_BLK_VQ_NUM 1
+#define VDPASIM_BLK_AS_NUM 1
+#define VDPASIM_BLK_GROUP_NUM 1
+
+static char vdpasim_blk_id[VIRTIO_BLK_ID_BYTES] = "vdpa_blk_sim";
+
+static bool vdpasim_blk_check_range(struct vdpasim *vdpasim, u64 start_sector,
+ u64 num_sectors, u64 max_sectors)
+{
+ if (start_sector > VDPASIM_BLK_CAPACITY) {
+ dev_dbg(&vdpasim->vdpa.dev,
+ "starting sector exceeds the capacity - start: 0x%llx capacity: 0x%x\n",
+ start_sector, VDPASIM_BLK_CAPACITY);
+ }
+
+ if (num_sectors > max_sectors) {
+ dev_dbg(&vdpasim->vdpa.dev,
+ "number of sectors exceeds the max allowed in a request - num: 0x%llx max: 0x%llx\n",
+ num_sectors, max_sectors);
+ return false;
+ }
+
+ if (num_sectors > VDPASIM_BLK_CAPACITY - start_sector) {
+ dev_dbg(&vdpasim->vdpa.dev,
+ "request exceeds the capacity - start: 0x%llx num: 0x%llx capacity: 0x%x\n",
+ start_sector, num_sectors, VDPASIM_BLK_CAPACITY);
+ 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;
+ bool handled = false;
+ 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_dbg(&vdpasim->vdpa.dev, "missing headers - out_iov: %u in_iov %u\n",
+ vq->out_iov.used, vq->in_iov.used);
+ goto err;
+ }
+
+ if (vq->in_iov.iov[vq->in_iov.used - 1].iov_len < 1) {
+ dev_dbg(&vdpasim->vdpa.dev, "request in header too short\n");
+ goto err;
+ }
+
+ /* 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_dbg(&vdpasim->vdpa.dev, "request out header too short\n");
+ goto err;
+ }
+
+ 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;
+
+ if (type != VIRTIO_BLK_T_IN && type != VIRTIO_BLK_T_OUT &&
+ sector != 0) {
+ dev_dbg(&vdpasim->vdpa.dev,
+ "sector must be 0 for %u request - sector: 0x%llx\n",
+ type, sector);
+ status = VIRTIO_BLK_S_IOERR;
+ goto err_status;
+ }
+
+ switch (type) {
+ case VIRTIO_BLK_T_IN:
+ if (!vdpasim_blk_check_range(vdpasim, sector,
+ to_push >> SECTOR_SHIFT,
+ VDPASIM_BLK_SIZE_MAX * VDPASIM_BLK_SEG_MAX)) {
+ 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_dbg(&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(vdpasim, sector,
+ to_pull >> SECTOR_SHIFT,
+ VDPASIM_BLK_SIZE_MAX * VDPASIM_BLK_SEG_MAX)) {
+ 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_dbg(&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_dbg(&vdpasim->vdpa.dev,
+ "vringh_iov_push_iotlb() error: %zd\n", bytes);
+ status = VIRTIO_BLK_S_IOERR;
+ break;
+ }
+
+ pushed += bytes;
+ break;
+
+ case VIRTIO_BLK_T_FLUSH:
+ /* nothing to do */
+ break;
+
+ case VIRTIO_BLK_T_DISCARD:
+ case VIRTIO_BLK_T_WRITE_ZEROES: {
+ struct virtio_blk_discard_write_zeroes range;
+ u32 num_sectors, flags;
+
+ if (to_pull != sizeof(range)) {
+ dev_dbg(&vdpasim->vdpa.dev,
+ "discard/write_zeroes header len: 0x%zx [expected: 0x%zx]\n",
+ to_pull, sizeof(range));
+ status = VIRTIO_BLK_S_IOERR;
+ break;
+ }
+
+ bytes = vringh_iov_pull_iotlb(&vq->vring, &vq->out_iov, &range,
+ to_pull);
+ if (bytes < 0) {
+ dev_dbg(&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;
+ }
+
+ sector = le64_to_cpu(range.sector);
+ offset = sector << SECTOR_SHIFT;
+ num_sectors = le32_to_cpu(range.num_sectors);
+ flags = le32_to_cpu(range.flags);
+
+ if (type == VIRTIO_BLK_T_DISCARD && flags != 0) {
+ dev_dbg(&vdpasim->vdpa.dev,
+ "discard unexpected flags set - flags: 0x%x\n",
+ flags);
+ status = VIRTIO_BLK_S_UNSUPP;
+ break;
+ }
+
+ if (type == VIRTIO_BLK_T_WRITE_ZEROES &&
+ flags & ~VIRTIO_BLK_WRITE_ZEROES_FLAG_UNMAP) {
+ dev_dbg(&vdpasim->vdpa.dev,
+ "write_zeroes unexpected flags set - flags: 0x%x\n",
+ flags);
+ status = VIRTIO_BLK_S_UNSUPP;
+ break;
+ }
+
+ if (!vdpasim_blk_check_range(vdpasim, sector, num_sectors,
+ VDPASIM_BLK_DWZ_MAX_SECTORS)) {
+ status = VIRTIO_BLK_S_IOERR;
+ break;
+ }
+
+ if (type == VIRTIO_BLK_T_WRITE_ZEROES) {
+ memset(vdpasim->buffer + offset, 0,
+ num_sectors << SECTOR_SHIFT);
+ }
+
+ break;
+ }
+ default:
+ dev_dbg(&vdpasim->vdpa.dev,
+ "Unsupported request type %d\n", type);
+ status = VIRTIO_BLK_S_IOERR;
+ break;
+ }
+
+err_status:
+ /* 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)
+ goto err;
+
+ pushed += bytes;
+
+ /* Make sure data is wrote before advancing index */
+ smp_wmb();
+
+ handled = true;
+
+err:
+ vringh_complete_iotlb(&vq->vring, vq->head, pushed);
+
+ return handled;
+}
+
+static void vdpasim_blk_work(struct work_struct *work)
+{
+ struct vdpasim *vdpasim = container_of(work, struct vdpasim, work);
+ bool reschedule = false;
+ int i;
+
+ spin_lock(&vdpasim->lock);
+
+ if (!(vdpasim->status & VIRTIO_CONFIG_S_DRIVER_OK))
+ goto out;
+
+ if (!vdpasim->running)
+ goto out;
+
+ for (i = 0; i < VDPASIM_BLK_VQ_NUM; i++) {
+ struct vdpasim_virtqueue *vq = &vdpasim->vqs[i];
+ int reqs = 0;
+
+ 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();
+
+ if (++reqs > 4) {
+ reschedule = true;
+ break;
+ }
+ }
+ }
+out:
+ spin_unlock(&vdpasim->lock);
+
+ if (reschedule)
+ schedule_work(&vdpasim->work);
+}
+
+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);
+ /* VIRTIO_BLK_F_DISCARD */
+ blk_config->discard_sector_alignment =
+ cpu_to_vdpasim32(vdpasim, SECTOR_SIZE);
+ blk_config->max_discard_sectors =
+ cpu_to_vdpasim32(vdpasim, VDPASIM_BLK_DWZ_MAX_SECTORS);
+ blk_config->max_discard_seg = cpu_to_vdpasim32(vdpasim, 1);
+ /* VIRTIO_BLK_F_WRITE_ZEROES */
+ blk_config->max_write_zeroes_sectors =
+ cpu_to_vdpasim32(vdpasim, VDPASIM_BLK_DWZ_MAX_SECTORS);
+ blk_config->max_write_zeroes_seg = cpu_to_vdpasim32(vdpasim, 1);
+
+}
+
+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,
+ const struct vdpa_dev_set_config *config)
+{
+ 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.ngroups = VDPASIM_BLK_GROUP_NUM;
+ dev_attr.nas = VDPASIM_BLK_AS_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, config);
+ 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) {
+ put_device(&vdpasim_blk_mgmtdev);
+ 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);