// SPDX-License-Identifier: GPL-2.0-only /* * VDPA device simulator core. * * Copyright (c) 2020, Red Hat Inc. All rights reserved. * Author: Jason Wang * */ #include #include #include #include #include #include #include #include #include #include #include #include "vdpa_sim.h" #define DRV_VERSION "0.1" #define DRV_AUTHOR "Jason Wang " #define DRV_DESC "vDPA Device Simulator core" #define DRV_LICENSE "GPL v2" static int batch_mapping = 1; module_param(batch_mapping, int, 0444); MODULE_PARM_DESC(batch_mapping, "Batched mapping 1 -Enable; 0 - Disable"); static int max_iotlb_entries = 2048; module_param(max_iotlb_entries, int, 0444); MODULE_PARM_DESC(max_iotlb_entries, "Maximum number of iotlb entries for each address space. 0 means unlimited. (default: 2048)"); static bool use_va = true; module_param(use_va, bool, 0444); MODULE_PARM_DESC(use_va, "Enable/disable the device's ability to use VA"); #define VDPASIM_QUEUE_ALIGN PAGE_SIZE #define VDPASIM_QUEUE_MAX 256 #define VDPASIM_VENDOR_ID 0 struct vdpasim_mm_work { struct kthread_work work; struct vdpasim *vdpasim; struct mm_struct *mm_to_bind; int ret; }; static void vdpasim_mm_work_fn(struct kthread_work *work) { struct vdpasim_mm_work *mm_work = container_of(work, struct vdpasim_mm_work, work); struct vdpasim *vdpasim = mm_work->vdpasim; mm_work->ret = 0; //TODO: should we attach the cgroup of the mm owner? vdpasim->mm_bound = mm_work->mm_to_bind; } static void vdpasim_worker_change_mm_sync(struct vdpasim *vdpasim, struct vdpasim_mm_work *mm_work) { struct kthread_work *work = &mm_work->work; kthread_init_work(work, vdpasim_mm_work_fn); kthread_queue_work(vdpasim->worker, work); kthread_flush_work(work); } static struct vdpasim *vdpa_to_sim(struct vdpa_device *vdpa) { return container_of(vdpa, struct vdpasim, vdpa); } static void vdpasim_vq_notify(struct vringh *vring) { struct vdpasim_virtqueue *vq = container_of(vring, struct vdpasim_virtqueue, vring); if (!vq->cb) return; vq->cb(vq->private); } static void vdpasim_queue_ready(struct vdpasim *vdpasim, unsigned int idx) { struct vdpasim_virtqueue *vq = &vdpasim->vqs[idx]; uint16_t last_avail_idx = vq->vring.last_avail_idx; struct vring_desc *desc = (struct vring_desc *) (uintptr_t)vq->desc_addr; struct vring_avail *avail = (struct vring_avail *) (uintptr_t)vq->driver_addr; struct vring_used *used = (struct vring_used *) (uintptr_t)vq->device_addr; if (use_va && vdpasim->mm_bound) { vringh_init_iotlb_va(&vq->vring, vdpasim->features, vq->num, true, desc, avail, used); } else { vringh_init_iotlb(&vq->vring, vdpasim->features, vq->num, true, desc, avail, used); } vq->vring.last_avail_idx = last_avail_idx; /* * Since vdpa_sim does not support receive inflight descriptors as a * destination of a migration, let's set both avail_idx and used_idx * the same at vq start. This is how vhost-user works in a * VHOST_SET_VRING_BASE call. * * Although the simple fix is to set last_used_idx at * vdpasim_set_vq_state, it would be reset at vdpasim_queue_ready. */ vq->vring.last_used_idx = last_avail_idx; vq->vring.notify = vdpasim_vq_notify; } static void vdpasim_vq_reset(struct vdpasim *vdpasim, struct vdpasim_virtqueue *vq) { vq->ready = false; vq->desc_addr = 0; vq->driver_addr = 0; vq->device_addr = 0; vq->cb = NULL; vq->private = NULL; vringh_init_iotlb(&vq->vring, vdpasim->dev_attr.supported_features, VDPASIM_QUEUE_MAX, false, NULL, NULL, NULL); vq->vring.notify = NULL; } static void vdpasim_do_reset(struct vdpasim *vdpasim) { int i; spin_lock(&vdpasim->iommu_lock); for (i = 0; i < vdpasim->dev_attr.nvqs; i++) { vdpasim_vq_reset(vdpasim, &vdpasim->vqs[i]); vringh_set_iotlb(&vdpasim->vqs[i].vring, &vdpasim->iommu[0], &vdpasim->iommu_lock); } for (i = 0; i < vdpasim->dev_attr.nas; i++) { vhost_iotlb_reset(&vdpasim->iommu[i]); vhost_iotlb_add_range(&vdpasim->iommu[i], 0, ULONG_MAX, 0, VHOST_MAP_RW); vdpasim->iommu_pt[i] = true; } vdpasim->running = true; spin_unlock(&vdpasim->iommu_lock); vdpasim->features = 0; vdpasim->status = 0; ++vdpasim->generation; } static const struct vdpa_config_ops vdpasim_config_ops; static const struct vdpa_config_ops vdpasim_batch_config_ops; static void vdpasim_work_fn(struct kthread_work *work) { struct vdpasim *vdpasim = container_of(work, struct vdpasim, work); struct mm_struct *mm = vdpasim->mm_bound; if (use_va && mm) { if (!mmget_not_zero(mm)) return; kthread_use_mm(mm); } vdpasim->dev_attr.work_fn(vdpasim); if (use_va && mm) { kthread_unuse_mm(mm); mmput(mm); } } struct vdpasim *vdpasim_create(struct vdpasim_dev_attr *dev_attr, const struct vdpa_dev_set_config *config) { const struct vdpa_config_ops *ops; struct vdpa_device *vdpa; struct vdpasim *vdpasim; struct device *dev; int i, ret = -ENOMEM; if (!dev_attr->alloc_size) return ERR_PTR(-EINVAL); if (config->mask & BIT_ULL(VDPA_ATTR_DEV_FEATURES)) { if (config->device_features & ~dev_attr->supported_features) return ERR_PTR(-EINVAL); dev_attr->supported_features = config->device_features; } if (batch_mapping) ops = &vdpasim_batch_config_ops; else ops = &vdpasim_config_ops; vdpa = __vdpa_alloc_device(NULL, ops, dev_attr->ngroups, dev_attr->nas, dev_attr->alloc_size, dev_attr->name, use_va); if (IS_ERR(vdpa)) { ret = PTR_ERR(vdpa); goto err_alloc; } vdpasim = vdpa_to_sim(vdpa); vdpasim->dev_attr = *dev_attr; dev = &vdpasim->vdpa.dev; kthread_init_work(&vdpasim->work, vdpasim_work_fn); vdpasim->worker = kthread_create_worker(0, "vDPA sim worker: %s", dev_attr->name); if (IS_ERR(vdpasim->worker)) goto err_iommu; mutex_init(&vdpasim->mutex); spin_lock_init(&vdpasim->iommu_lock); dev->dma_mask = &dev->coherent_dma_mask; if (dma_set_mask_and_coherent(dev, DMA_BIT_MASK(64))) goto err_iommu; vdpasim->vdpa.mdev = dev_attr->mgmt_dev; vdpasim->config = kzalloc(dev_attr->config_size, GFP_KERNEL); if (!vdpasim->config) goto err_iommu; vdpasim->vqs = kcalloc(dev_attr->nvqs, sizeof(struct vdpasim_virtqueue), GFP_KERNEL); if (!vdpasim->vqs) goto err_iommu; vdpasim->iommu = kmalloc_array(vdpasim->dev_attr.nas, sizeof(*vdpasim->iommu), GFP_KERNEL); if (!vdpasim->iommu) goto err_iommu; vdpasim->iommu_pt = kmalloc_array(vdpasim->dev_attr.nas, sizeof(*vdpasim->iommu_pt), GFP_KERNEL); if (!vdpasim->iommu_pt) goto err_iommu; for (i = 0; i < vdpasim->dev_attr.nas; i++) vhost_iotlb_init(&vdpasim->iommu[i], max_iotlb_entries, 0); vdpasim->buffer = kvmalloc(dev_attr->buffer_size, GFP_KERNEL); if (!vdpasim->buffer) goto err_iommu; for (i = 0; i < dev_attr->nvqs; i++) vringh_set_iotlb(&vdpasim->vqs[i].vring, &vdpasim->iommu[0], &vdpasim->iommu_lock); vdpasim->vdpa.dma_dev = dev; return vdpasim; err_iommu: put_device(dev); err_alloc: return ERR_PTR(ret); } EXPORT_SYMBOL_GPL(vdpasim_create); void vdpasim_schedule_work(struct vdpasim *vdpasim) { kthread_queue_work(vdpasim->worker, &vdpasim->work); } EXPORT_SYMBOL_GPL(vdpasim_schedule_work); static int vdpasim_set_vq_address(struct vdpa_device *vdpa, u16 idx, u64 desc_area, u64 driver_area, u64 device_area) { struct vdpasim *vdpasim = vdpa_to_sim(vdpa); struct vdpasim_virtqueue *vq = &vdpasim->vqs[idx]; vq->desc_addr = desc_area; vq->driver_addr = driver_area; vq->device_addr = device_area; return 0; } static void vdpasim_set_vq_num(struct vdpa_device *vdpa, u16 idx, u32 num) { struct vdpasim *vdpasim = vdpa_to_sim(vdpa); struct vdpasim_virtqueue *vq = &vdpasim->vqs[idx]; vq->num = num; } static void vdpasim_kick_vq(struct vdpa_device *vdpa, u16 idx) { struct vdpasim *vdpasim = vdpa_to_sim(vdpa); struct vdpasim_virtqueue *vq = &vdpasim->vqs[idx]; if (!vdpasim->running && (vdpasim->status & VIRTIO_CONFIG_S_DRIVER_OK)) { vdpasim->pending_kick = true; return; } if (vq->ready) vdpasim_schedule_work(vdpasim); } static void vdpasim_set_vq_cb(struct vdpa_device *vdpa, u16 idx, struct vdpa_callback *cb) { struct vdpasim *vdpasim = vdpa_to_sim(vdpa); struct vdpasim_virtqueue *vq = &vdpasim->vqs[idx]; vq->cb = cb->callback; vq->private = cb->private; } static void vdpasim_set_vq_ready(struct vdpa_device *vdpa, u16 idx, bool ready) { struct vdpasim *vdpasim = vdpa_to_sim(vdpa); struct vdpasim_virtqueue *vq = &vdpasim->vqs[idx]; bool old_ready; mutex_lock(&vdpasim->mutex); old_ready = vq->ready; vq->ready = ready; if (vq->ready && !old_ready) { vdpasim_queue_ready(vdpasim, idx); } mutex_unlock(&vdpasim->mutex); } static bool vdpasim_get_vq_ready(struct vdpa_device *vdpa, u16 idx) { struct vdpasim *vdpasim = vdpa_to_sim(vdpa); struct vdpasim_virtqueue *vq = &vdpasim->vqs[idx]; return vq->ready; } static int vdpasim_set_vq_state(struct vdpa_device *vdpa, u16 idx, const struct vdpa_vq_state *state) { struct vdpasim *vdpasim = vdpa_to_sim(vdpa); struct vdpasim_virtqueue *vq = &vdpasim->vqs[idx]; struct vringh *vrh = &vq->vring; mutex_lock(&vdpasim->mutex); vrh->last_avail_idx = state->split.avail_index; mutex_unlock(&vdpasim->mutex); return 0; } static int vdpasim_get_vq_state(struct vdpa_device *vdpa, u16 idx, struct vdpa_vq_state *state) { struct vdpasim *vdpasim = vdpa_to_sim(vdpa); struct vdpasim_virtqueue *vq = &vdpasim->vqs[idx]; struct vringh *vrh = &vq->vring; state->split.avail_index = vrh->last_avail_idx; return 0; } static int vdpasim_get_vq_stats(struct vdpa_device *vdpa, u16 idx, struct sk_buff *msg, struct netlink_ext_ack *extack) { struct vdpasim *vdpasim = vdpa_to_sim(vdpa); if (vdpasim->dev_attr.get_stats) return vdpasim->dev_attr.get_stats(vdpasim, idx, msg, extack); return -EOPNOTSUPP; } static u32 vdpasim_get_vq_align(struct vdpa_device *vdpa) { return VDPASIM_QUEUE_ALIGN; } static u32 vdpasim_get_vq_group(struct vdpa_device *vdpa, u16 idx) { /* RX and TX belongs to group 0, CVQ belongs to group 1 */ if (idx == 2) return 1; else return 0; } static u64 vdpasim_get_device_features(struct vdpa_device *vdpa) { struct vdpasim *vdpasim = vdpa_to_sim(vdpa); return vdpasim->dev_attr.supported_features; } static int vdpasim_set_driver_features(struct vdpa_device *vdpa, u64 features) { struct vdpasim *vdpasim = vdpa_to_sim(vdpa); /* DMA mapping must be done by driver */ if (!(features & (1ULL << VIRTIO_F_ACCESS_PLATFORM))) return -EINVAL; vdpasim->features = features & vdpasim->dev_attr.supported_features; return 0; } static u64 vdpasim_get_driver_features(struct vdpa_device *vdpa) { struct vdpasim *vdpasim = vdpa_to_sim(vdpa); return vdpasim->features; } static void vdpasim_set_config_cb(struct vdpa_device *vdpa, struct vdpa_callback *cb) { /* We don't support config interrupt */ } static u16 vdpasim_get_vq_num_max(struct vdpa_device *vdpa) { return VDPASIM_QUEUE_MAX; } static u32 vdpasim_get_device_id(struct vdpa_device *vdpa) { struct vdpasim *vdpasim = vdpa_to_sim(vdpa); return vdpasim->dev_attr.id; } static u32 vdpasim_get_vendor_id(struct vdpa_device *vdpa) { return VDPASIM_VENDOR_ID; } static u8 vdpasim_get_status(struct vdpa_device *vdpa) { struct vdpasim *vdpasim = vdpa_to_sim(vdpa); u8 status; mutex_lock(&vdpasim->mutex); status = vdpasim->status; mutex_unlock(&vdpasim->mutex); return status; } static void vdpasim_set_status(struct vdpa_device *vdpa, u8 status) { struct vdpasim *vdpasim = vdpa_to_sim(vdpa); mutex_lock(&vdpasim->mutex); vdpasim->status = status; mutex_unlock(&vdpasim->mutex); } static int vdpasim_reset(struct vdpa_device *vdpa) { struct vdpasim *vdpasim = vdpa_to_sim(vdpa); mutex_lock(&vdpasim->mutex); vdpasim->status = 0; vdpasim_do_reset(vdpasim); mutex_unlock(&vdpasim->mutex); return 0; } static int vdpasim_suspend(struct vdpa_device *vdpa) { struct vdpasim *vdpasim = vdpa_to_sim(vdpa); mutex_lock(&vdpasim->mutex); vdpasim->running = false; mutex_unlock(&vdpasim->mutex); return 0; } static int vdpasim_resume(struct vdpa_device *vdpa) { struct vdpasim *vdpasim = vdpa_to_sim(vdpa); int i; mutex_lock(&vdpasim->mutex); vdpasim->running = true; if (vdpasim->pending_kick) { /* Process pending descriptors */ for (i = 0; i < vdpasim->dev_attr.nvqs; ++i) vdpasim_kick_vq(vdpa, i); vdpasim->pending_kick = false; } mutex_unlock(&vdpasim->mutex); return 0; } static size_t vdpasim_get_config_size(struct vdpa_device *vdpa) { struct vdpasim *vdpasim = vdpa_to_sim(vdpa); return vdpasim->dev_attr.config_size; } static void vdpasim_get_config(struct vdpa_device *vdpa, unsigned int offset, void *buf, unsigned int len) { struct vdpasim *vdpasim = vdpa_to_sim(vdpa); if (offset + len > vdpasim->dev_attr.config_size) return; if (vdpasim->dev_attr.get_config) vdpasim->dev_attr.get_config(vdpasim, vdpasim->config); memcpy(buf, vdpasim->config + offset, len); } static void vdpasim_set_config(struct vdpa_device *vdpa, unsigned int offset, const void *buf, unsigned int len) { struct vdpasim *vdpasim = vdpa_to_sim(vdpa); if (offset + len > vdpasim->dev_attr.config_size) return; memcpy(vdpasim->config + offset, buf, len); if (vdpasim->dev_attr.set_config) vdpasim->dev_attr.set_config(vdpasim, vdpasim->config); } static u32 vdpasim_get_generation(struct vdpa_device *vdpa) { struct vdpasim *vdpasim = vdpa_to_sim(vdpa); return vdpasim->generation; } static struct vdpa_iova_range vdpasim_get_iova_range(struct vdpa_device *vdpa) { struct vdpa_iova_range range = { .first = 0ULL, .last = ULLONG_MAX, }; return range; } static int vdpasim_set_group_asid(struct vdpa_device *vdpa, unsigned int group, unsigned int asid) { struct vdpasim *vdpasim = vdpa_to_sim(vdpa); struct vhost_iotlb *iommu; int i; if (group > vdpasim->dev_attr.ngroups) return -EINVAL; if (asid >= vdpasim->dev_attr.nas) return -EINVAL; iommu = &vdpasim->iommu[asid]; mutex_lock(&vdpasim->mutex); for (i = 0; i < vdpasim->dev_attr.nvqs; i++) if (vdpasim_get_vq_group(vdpa, i) == group) vringh_set_iotlb(&vdpasim->vqs[i].vring, iommu, &vdpasim->iommu_lock); mutex_unlock(&vdpasim->mutex); return 0; } static int vdpasim_set_map(struct vdpa_device *vdpa, unsigned int asid, struct vhost_iotlb *iotlb) { struct vdpasim *vdpasim = vdpa_to_sim(vdpa); struct vhost_iotlb_map *map; struct vhost_iotlb *iommu; u64 start = 0ULL, last = 0ULL - 1; int ret; if (asid >= vdpasim->dev_attr.nas) return -EINVAL; spin_lock(&vdpasim->iommu_lock); iommu = &vdpasim->iommu[asid]; vhost_iotlb_reset(iommu); vdpasim->iommu_pt[asid] = false; for (map = vhost_iotlb_itree_first(iotlb, start, last); map; map = vhost_iotlb_itree_next(map, start, last)) { ret = vhost_iotlb_add_range(iommu, map->start, map->last, map->addr, map->perm); if (ret) goto err; } spin_unlock(&vdpasim->iommu_lock); return 0; err: vhost_iotlb_reset(iommu); spin_unlock(&vdpasim->iommu_lock); return ret; } static int vdpasim_bind_mm(struct vdpa_device *vdpa, struct mm_struct *mm) { struct vdpasim *vdpasim = vdpa_to_sim(vdpa); struct vdpasim_mm_work mm_work; mm_work.vdpasim = vdpasim; mm_work.mm_to_bind = mm; vdpasim_worker_change_mm_sync(vdpasim, &mm_work); return mm_work.ret; } static void vdpasim_unbind_mm(struct vdpa_device *vdpa) { struct vdpasim *vdpasim = vdpa_to_sim(vdpa); struct vdpasim_mm_work mm_work; mm_work.vdpasim = vdpasim; mm_work.mm_to_bind = NULL; vdpasim_worker_change_mm_sync(vdpasim, &mm_work); } static int vdpasim_dma_map(struct vdpa_device *vdpa, unsigned int asid, u64 iova, u64 size, u64 pa, u32 perm, void *opaque) { struct vdpasim *vdpasim = vdpa_to_sim(vdpa); int ret; if (asid >= vdpasim->dev_attr.nas) return -EINVAL; spin_lock(&vdpasim->iommu_lock); if (vdpasim->iommu_pt[asid]) { vhost_iotlb_reset(&vdpasim->iommu[asid]); vdpasim->iommu_pt[asid] = false; } ret = vhost_iotlb_add_range_ctx(&vdpasim->iommu[asid], iova, iova + size - 1, pa, perm, opaque); spin_unlock(&vdpasim->iommu_lock); return ret; } static int vdpasim_dma_unmap(struct vdpa_device *vdpa, unsigned int asid, u64 iova, u64 size) { struct vdpasim *vdpasim = vdpa_to_sim(vdpa); if (asid >= vdpasim->dev_attr.nas) return -EINVAL; if (vdpasim->iommu_pt[asid]) { vhost_iotlb_reset(&vdpasim->iommu[asid]); vdpasim->iommu_pt[asid] = false; } spin_lock(&vdpasim->iommu_lock); vhost_iotlb_del_range(&vdpasim->iommu[asid], iova, iova + size - 1); spin_unlock(&vdpasim->iommu_lock); return 0; } static void vdpasim_free(struct vdpa_device *vdpa) { struct vdpasim *vdpasim = vdpa_to_sim(vdpa); int i; kthread_cancel_work_sync(&vdpasim->work); kthread_destroy_worker(vdpasim->worker); for (i = 0; i < vdpasim->dev_attr.nvqs; i++) { vringh_kiov_cleanup(&vdpasim->vqs[i].out_iov); vringh_kiov_cleanup(&vdpasim->vqs[i].in_iov); } kvfree(vdpasim->buffer); for (i = 0; i < vdpasim->dev_attr.nas; i++) vhost_iotlb_reset(&vdpasim->iommu[i]); kfree(vdpasim->iommu); kfree(vdpasim->iommu_pt); kfree(vdpasim->vqs); kfree(vdpasim->config); } static const struct vdpa_config_ops vdpasim_config_ops = { .set_vq_address = vdpasim_set_vq_address, .set_vq_num = vdpasim_set_vq_num, .kick_vq = vdpasim_kick_vq, .set_vq_cb = vdpasim_set_vq_cb, .set_vq_ready = vdpasim_set_vq_ready, .get_vq_ready = vdpasim_get_vq_ready, .set_vq_state = vdpasim_set_vq_state, .get_vendor_vq_stats = vdpasim_get_vq_stats, .get_vq_state = vdpasim_get_vq_state, .get_vq_align = vdpasim_get_vq_align, .get_vq_group = vdpasim_get_vq_group, .get_device_features = vdpasim_get_device_features, .set_driver_features = vdpasim_set_driver_features, .get_driver_features = vdpasim_get_driver_features, .set_config_cb = vdpasim_set_config_cb, .get_vq_num_max = vdpasim_get_vq_num_max, .get_device_id = vdpasim_get_device_id, .get_vendor_id = vdpasim_get_vendor_id, .get_status = vdpasim_get_status, .set_status = vdpasim_set_status, .reset = vdpasim_reset, .suspend = vdpasim_suspend, .resume = vdpasim_resume, .get_config_size = vdpasim_get_config_size, .get_config = vdpasim_get_config, .set_config = vdpasim_set_config, .get_generation = vdpasim_get_generation, .get_iova_range = vdpasim_get_iova_range, .set_group_asid = vdpasim_set_group_asid, .dma_map = vdpasim_dma_map, .dma_unmap = vdpasim_dma_unmap, .bind_mm = vdpasim_bind_mm, .unbind_mm = vdpasim_unbind_mm, .free = vdpasim_free, }; static const struct vdpa_config_ops vdpasim_batch_config_ops = { .set_vq_address = vdpasim_set_vq_address, .set_vq_num = vdpasim_set_vq_num, .kick_vq = vdpasim_kick_vq, .set_vq_cb = vdpasim_set_vq_cb, .set_vq_ready = vdpasim_set_vq_ready, .get_vq_ready = vdpasim_get_vq_ready, .set_vq_state = vdpasim_set_vq_state, .get_vendor_vq_stats = vdpasim_get_vq_stats, .get_vq_state = vdpasim_get_vq_state, .get_vq_align = vdpasim_get_vq_align, .get_vq_group = vdpasim_get_vq_group, .get_device_features = vdpasim_get_device_features, .set_driver_features = vdpasim_set_driver_features, .get_driver_features = vdpasim_get_driver_features, .set_config_cb = vdpasim_set_config_cb, .get_vq_num_max = vdpasim_get_vq_num_max, .get_device_id = vdpasim_get_device_id, .get_vendor_id = vdpasim_get_vendor_id, .get_status = vdpasim_get_status, .set_status = vdpasim_set_status, .reset = vdpasim_reset, .suspend = vdpasim_suspend, .resume = vdpasim_resume, .get_config_size = vdpasim_get_config_size, .get_config = vdpasim_get_config, .set_config = vdpasim_set_config, .get_generation = vdpasim_get_generation, .get_iova_range = vdpasim_get_iova_range, .set_group_asid = vdpasim_set_group_asid, .set_map = vdpasim_set_map, .bind_mm = vdpasim_bind_mm, .unbind_mm = vdpasim_unbind_mm, .free = vdpasim_free, }; MODULE_VERSION(DRV_VERSION); MODULE_LICENSE(DRV_LICENSE); MODULE_AUTHOR(DRV_AUTHOR); MODULE_DESCRIPTION(DRV_DESC);