diff options
Diffstat (limited to 'drivers/dma/idxd/cdev.c')
| -rw-r--r-- | drivers/dma/idxd/cdev.c | 692 |
1 files changed, 692 insertions, 0 deletions
diff --git a/drivers/dma/idxd/cdev.c b/drivers/dma/idxd/cdev.c new file mode 100644 index 000000000..d32deb9b4 --- /dev/null +++ b/drivers/dma/idxd/cdev.c @@ -0,0 +1,692 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright(c) 2019 Intel Corporation. All rights rsvd. */ +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/pci.h> +#include <linux/device.h> +#include <linux/sched/task.h> +#include <linux/io-64-nonatomic-lo-hi.h> +#include <linux/cdev.h> +#include <linux/fs.h> +#include <linux/poll.h> +#include <linux/iommu.h> +#include <linux/highmem.h> +#include <uapi/linux/idxd.h> +#include <linux/xarray.h> +#include "registers.h" +#include "idxd.h" + +struct idxd_cdev_context { + const char *name; + dev_t devt; + struct ida minor_ida; +}; + +/* + * Since user file names are global in DSA devices, define their ida's as + * global to avoid conflict file names. + */ +static DEFINE_IDA(file_ida); +static DEFINE_MUTEX(ida_lock); + +/* + * ictx is an array based off of accelerator types. enum idxd_type + * is used as index + */ +static struct idxd_cdev_context ictx[IDXD_TYPE_MAX] = { + { .name = "dsa" }, + { .name = "iax" } +}; + +struct idxd_user_context { + struct idxd_wq *wq; + struct task_struct *task; + unsigned int pasid; + struct mm_struct *mm; + unsigned int flags; + struct iommu_sva *sva; + struct idxd_dev idxd_dev; + u64 counters[COUNTER_MAX]; + int id; + pid_t pid; +}; + +static void idxd_cdev_evl_drain_pasid(struct idxd_wq *wq, u32 pasid); +static void idxd_xa_pasid_remove(struct idxd_user_context *ctx); + +static inline struct idxd_user_context *dev_to_uctx(struct device *dev) +{ + struct idxd_dev *idxd_dev = confdev_to_idxd_dev(dev); + + return container_of(idxd_dev, struct idxd_user_context, idxd_dev); +} + +static ssize_t cr_faults_show(struct device *dev, struct device_attribute *attr, char *buf) +{ + struct idxd_user_context *ctx = dev_to_uctx(dev); + + return sysfs_emit(buf, "%llu\n", ctx->counters[COUNTER_FAULTS]); +} +static DEVICE_ATTR_RO(cr_faults); + +static ssize_t cr_fault_failures_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct idxd_user_context *ctx = dev_to_uctx(dev); + + return sysfs_emit(buf, "%llu\n", ctx->counters[COUNTER_FAULT_FAILS]); +} +static DEVICE_ATTR_RO(cr_fault_failures); + +static ssize_t pid_show(struct device *dev, struct device_attribute *attr, char *buf) +{ + struct idxd_user_context *ctx = dev_to_uctx(dev); + + return sysfs_emit(buf, "%u\n", ctx->pid); +} +static DEVICE_ATTR_RO(pid); + +static struct attribute *cdev_file_attributes[] = { + &dev_attr_cr_faults.attr, + &dev_attr_cr_fault_failures.attr, + &dev_attr_pid.attr, + NULL +}; + +static umode_t cdev_file_attr_visible(struct kobject *kobj, struct attribute *a, int n) +{ + struct device *dev = container_of(kobj, typeof(*dev), kobj); + struct idxd_user_context *ctx = dev_to_uctx(dev); + struct idxd_wq *wq = ctx->wq; + + if (!wq_pasid_enabled(wq)) + return 0; + + return a->mode; +} + +static const struct attribute_group cdev_file_attribute_group = { + .attrs = cdev_file_attributes, + .is_visible = cdev_file_attr_visible, +}; + +static const struct attribute_group *cdev_file_attribute_groups[] = { + &cdev_file_attribute_group, + NULL +}; + +static void idxd_file_dev_release(struct device *dev) +{ + struct idxd_user_context *ctx = dev_to_uctx(dev); + struct idxd_wq *wq = ctx->wq; + struct idxd_device *idxd = wq->idxd; + int rc; + + mutex_lock(&ida_lock); + ida_free(&file_ida, ctx->id); + mutex_unlock(&ida_lock); + + /* Wait for in-flight operations to complete. */ + if (wq_shared(wq)) { + idxd_device_drain_pasid(idxd, ctx->pasid); + } else { + if (device_user_pasid_enabled(idxd)) { + /* The wq disable in the disable pasid function will drain the wq */ + rc = idxd_wq_disable_pasid(wq); + if (rc < 0) + dev_err(dev, "wq disable pasid failed.\n"); + } else { + idxd_wq_drain(wq); + } + } + + if (ctx->sva) { + idxd_cdev_evl_drain_pasid(wq, ctx->pasid); + iommu_sva_unbind_device(ctx->sva); + idxd_xa_pasid_remove(ctx); + } + kfree(ctx); + mutex_lock(&wq->wq_lock); + idxd_wq_put(wq); + mutex_unlock(&wq->wq_lock); +} + +static struct device_type idxd_cdev_file_type = { + .name = "idxd_file", + .release = idxd_file_dev_release, + .groups = cdev_file_attribute_groups, +}; + +static void idxd_cdev_dev_release(struct device *dev) +{ + struct idxd_cdev *idxd_cdev = dev_to_cdev(dev); + struct idxd_cdev_context *cdev_ctx; + struct idxd_wq *wq = idxd_cdev->wq; + + cdev_ctx = &ictx[wq->idxd->data->type]; + ida_simple_remove(&cdev_ctx->minor_ida, idxd_cdev->minor); + kfree(idxd_cdev); +} + +static struct device_type idxd_cdev_device_type = { + .name = "idxd_cdev", + .release = idxd_cdev_dev_release, +}; + +static inline struct idxd_cdev *inode_idxd_cdev(struct inode *inode) +{ + struct cdev *cdev = inode->i_cdev; + + return container_of(cdev, struct idxd_cdev, cdev); +} + +static inline struct idxd_wq *inode_wq(struct inode *inode) +{ + struct idxd_cdev *idxd_cdev = inode_idxd_cdev(inode); + + return idxd_cdev->wq; +} + +static void idxd_xa_pasid_remove(struct idxd_user_context *ctx) +{ + struct idxd_wq *wq = ctx->wq; + void *ptr; + + mutex_lock(&wq->uc_lock); + ptr = xa_cmpxchg(&wq->upasid_xa, ctx->pasid, ctx, NULL, GFP_KERNEL); + if (ptr != (void *)ctx) + dev_warn(&wq->idxd->pdev->dev, "xarray cmpxchg failed for pasid %u\n", + ctx->pasid); + mutex_unlock(&wq->uc_lock); +} + +void idxd_user_counter_increment(struct idxd_wq *wq, u32 pasid, int index) +{ + struct idxd_user_context *ctx; + + if (index >= COUNTER_MAX) + return; + + mutex_lock(&wq->uc_lock); + ctx = xa_load(&wq->upasid_xa, pasid); + if (!ctx) { + mutex_unlock(&wq->uc_lock); + return; + } + ctx->counters[index]++; + mutex_unlock(&wq->uc_lock); +} + +static int idxd_cdev_open(struct inode *inode, struct file *filp) +{ + struct idxd_user_context *ctx; + struct idxd_device *idxd; + struct idxd_wq *wq; + struct device *dev, *fdev; + int rc = 0; + struct iommu_sva *sva; + unsigned int pasid; + struct idxd_cdev *idxd_cdev; + + wq = inode_wq(inode); + idxd = wq->idxd; + dev = &idxd->pdev->dev; + + dev_dbg(dev, "%s called: %d\n", __func__, idxd_wq_refcount(wq)); + + ctx = kzalloc(sizeof(*ctx), GFP_KERNEL); + if (!ctx) + return -ENOMEM; + + mutex_lock(&wq->wq_lock); + + if (idxd_wq_refcount(wq) > 0 && wq_dedicated(wq)) { + rc = -EBUSY; + goto failed; + } + + ctx->wq = wq; + filp->private_data = ctx; + ctx->pid = current->pid; + + if (device_user_pasid_enabled(idxd)) { + sva = iommu_sva_bind_device(dev, current->mm); + if (IS_ERR(sva)) { + rc = PTR_ERR(sva); + dev_err(dev, "pasid allocation failed: %d\n", rc); + goto failed; + } + + pasid = iommu_sva_get_pasid(sva); + if (pasid == IOMMU_PASID_INVALID) { + rc = -EINVAL; + goto failed_get_pasid; + } + + ctx->sva = sva; + ctx->pasid = pasid; + ctx->mm = current->mm; + + mutex_lock(&wq->uc_lock); + rc = xa_insert(&wq->upasid_xa, pasid, ctx, GFP_KERNEL); + mutex_unlock(&wq->uc_lock); + if (rc < 0) + dev_warn(dev, "PASID entry already exist in xarray.\n"); + + if (wq_dedicated(wq)) { + rc = idxd_wq_set_pasid(wq, pasid); + if (rc < 0) { + dev_err(dev, "wq set pasid failed: %d\n", rc); + goto failed_set_pasid; + } + } + } + + idxd_cdev = wq->idxd_cdev; + mutex_lock(&ida_lock); + ctx->id = ida_alloc(&file_ida, GFP_KERNEL); + mutex_unlock(&ida_lock); + if (ctx->id < 0) { + dev_warn(dev, "ida alloc failure\n"); + goto failed_ida; + } + ctx->idxd_dev.type = IDXD_DEV_CDEV_FILE; + fdev = user_ctx_dev(ctx); + device_initialize(fdev); + fdev->parent = cdev_dev(idxd_cdev); + fdev->bus = &dsa_bus_type; + fdev->type = &idxd_cdev_file_type; + + rc = dev_set_name(fdev, "file%d", ctx->id); + if (rc < 0) { + dev_warn(dev, "set name failure\n"); + goto failed_dev_name; + } + + rc = device_add(fdev); + if (rc < 0) { + dev_warn(dev, "file device add failure\n"); + goto failed_dev_add; + } + + idxd_wq_get(wq); + mutex_unlock(&wq->wq_lock); + return 0; + +failed_dev_add: +failed_dev_name: + put_device(fdev); +failed_ida: +failed_set_pasid: + if (device_user_pasid_enabled(idxd)) + idxd_xa_pasid_remove(ctx); +failed_get_pasid: + if (device_user_pasid_enabled(idxd)) + iommu_sva_unbind_device(sva); +failed: + mutex_unlock(&wq->wq_lock); + kfree(ctx); + return rc; +} + +static void idxd_cdev_evl_drain_pasid(struct idxd_wq *wq, u32 pasid) +{ + struct idxd_device *idxd = wq->idxd; + struct idxd_evl *evl = idxd->evl; + union evl_status_reg status; + u16 h, t, size; + int ent_size = evl_ent_size(idxd); + struct __evl_entry *entry_head; + + if (!evl) + return; + + spin_lock(&evl->lock); + status.bits = ioread64(idxd->reg_base + IDXD_EVLSTATUS_OFFSET); + t = status.tail; + h = evl->head; + size = evl->size; + + while (h != t) { + entry_head = (struct __evl_entry *)(evl->log + (h * ent_size)); + if (entry_head->pasid == pasid && entry_head->wq_idx == wq->id) + set_bit(h, evl->bmap); + h = (h + 1) % size; + } + spin_unlock(&evl->lock); + + drain_workqueue(wq->wq); +} + +static int idxd_cdev_release(struct inode *node, struct file *filep) +{ + struct idxd_user_context *ctx = filep->private_data; + struct idxd_wq *wq = ctx->wq; + struct idxd_device *idxd = wq->idxd; + struct device *dev = &idxd->pdev->dev; + + dev_dbg(dev, "%s called\n", __func__); + filep->private_data = NULL; + + device_unregister(user_ctx_dev(ctx)); + + return 0; +} + +static int check_vma(struct idxd_wq *wq, struct vm_area_struct *vma, + const char *func) +{ + struct device *dev = &wq->idxd->pdev->dev; + + if ((vma->vm_end - vma->vm_start) > PAGE_SIZE) { + dev_info_ratelimited(dev, + "%s: %s: mapping too large: %lu\n", + current->comm, func, + vma->vm_end - vma->vm_start); + return -EINVAL; + } + + return 0; +} + +static int idxd_cdev_mmap(struct file *filp, struct vm_area_struct *vma) +{ + struct idxd_user_context *ctx = filp->private_data; + struct idxd_wq *wq = ctx->wq; + struct idxd_device *idxd = wq->idxd; + struct pci_dev *pdev = idxd->pdev; + phys_addr_t base = pci_resource_start(pdev, IDXD_WQ_BAR); + unsigned long pfn; + int rc; + + dev_dbg(&pdev->dev, "%s called\n", __func__); + rc = check_vma(wq, vma, __func__); + if (rc < 0) + return rc; + + vm_flags_set(vma, VM_DONTCOPY); + pfn = (base + idxd_get_wq_portal_full_offset(wq->id, + IDXD_PORTAL_LIMITED)) >> PAGE_SHIFT; + vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); + vma->vm_private_data = ctx; + + return io_remap_pfn_range(vma, vma->vm_start, pfn, PAGE_SIZE, + vma->vm_page_prot); +} + +static __poll_t idxd_cdev_poll(struct file *filp, + struct poll_table_struct *wait) +{ + struct idxd_user_context *ctx = filp->private_data; + struct idxd_wq *wq = ctx->wq; + struct idxd_device *idxd = wq->idxd; + __poll_t out = 0; + + poll_wait(filp, &wq->err_queue, wait); + spin_lock(&idxd->dev_lock); + if (idxd->sw_err.valid) + out = EPOLLIN | EPOLLRDNORM; + spin_unlock(&idxd->dev_lock); + + return out; +} + +static const struct file_operations idxd_cdev_fops = { + .owner = THIS_MODULE, + .open = idxd_cdev_open, + .release = idxd_cdev_release, + .mmap = idxd_cdev_mmap, + .poll = idxd_cdev_poll, +}; + +int idxd_cdev_get_major(struct idxd_device *idxd) +{ + return MAJOR(ictx[idxd->data->type].devt); +} + +int idxd_wq_add_cdev(struct idxd_wq *wq) +{ + struct idxd_device *idxd = wq->idxd; + struct idxd_cdev *idxd_cdev; + struct cdev *cdev; + struct device *dev; + struct idxd_cdev_context *cdev_ctx; + int rc, minor; + + idxd_cdev = kzalloc(sizeof(*idxd_cdev), GFP_KERNEL); + if (!idxd_cdev) + return -ENOMEM; + + idxd_cdev->idxd_dev.type = IDXD_DEV_CDEV; + idxd_cdev->wq = wq; + cdev = &idxd_cdev->cdev; + dev = cdev_dev(idxd_cdev); + cdev_ctx = &ictx[wq->idxd->data->type]; + minor = ida_simple_get(&cdev_ctx->minor_ida, 0, MINORMASK, GFP_KERNEL); + if (minor < 0) { + kfree(idxd_cdev); + return minor; + } + idxd_cdev->minor = minor; + + device_initialize(dev); + dev->parent = wq_confdev(wq); + dev->bus = &dsa_bus_type; + dev->type = &idxd_cdev_device_type; + dev->devt = MKDEV(MAJOR(cdev_ctx->devt), minor); + + rc = dev_set_name(dev, "%s/wq%u.%u", idxd->data->name_prefix, idxd->id, wq->id); + if (rc < 0) + goto err; + + wq->idxd_cdev = idxd_cdev; + cdev_init(cdev, &idxd_cdev_fops); + rc = cdev_device_add(cdev, dev); + if (rc) { + dev_dbg(&wq->idxd->pdev->dev, "cdev_add failed: %d\n", rc); + goto err; + } + + return 0; + + err: + put_device(dev); + wq->idxd_cdev = NULL; + return rc; +} + +void idxd_wq_del_cdev(struct idxd_wq *wq) +{ + struct idxd_cdev *idxd_cdev; + + idxd_cdev = wq->idxd_cdev; + ida_destroy(&file_ida); + wq->idxd_cdev = NULL; + cdev_device_del(&idxd_cdev->cdev, cdev_dev(idxd_cdev)); + put_device(cdev_dev(idxd_cdev)); +} + +static int idxd_user_drv_probe(struct idxd_dev *idxd_dev) +{ + struct idxd_wq *wq = idxd_dev_to_wq(idxd_dev); + struct idxd_device *idxd = wq->idxd; + int rc; + + if (idxd->state != IDXD_DEV_ENABLED) + return -ENXIO; + + /* + * User type WQ is enabled only when SVA is enabled for two reasons: + * - If no IOMMU or IOMMU Passthrough without SVA, userspace + * can directly access physical address through the WQ. + * - The IDXD cdev driver does not provide any ways to pin + * user pages and translate the address from user VA to IOVA or + * PA without IOMMU SVA. Therefore the application has no way + * to instruct the device to perform DMA function. This makes + * the cdev not usable for normal application usage. + */ + if (!device_user_pasid_enabled(idxd)) { + idxd->cmd_status = IDXD_SCMD_WQ_USER_NO_IOMMU; + dev_dbg(&idxd->pdev->dev, + "User type WQ cannot be enabled without SVA.\n"); + + return -EOPNOTSUPP; + } + + mutex_lock(&wq->wq_lock); + + wq->wq = create_workqueue(dev_name(wq_confdev(wq))); + if (!wq->wq) { + rc = -ENOMEM; + goto wq_err; + } + + wq->type = IDXD_WQT_USER; + rc = drv_enable_wq(wq); + if (rc < 0) + goto err; + + rc = idxd_wq_add_cdev(wq); + if (rc < 0) { + idxd->cmd_status = IDXD_SCMD_CDEV_ERR; + goto err_cdev; + } + + idxd->cmd_status = 0; + mutex_unlock(&wq->wq_lock); + return 0; + +err_cdev: + drv_disable_wq(wq); +err: + destroy_workqueue(wq->wq); + wq->type = IDXD_WQT_NONE; +wq_err: + mutex_unlock(&wq->wq_lock); + return rc; +} + +static void idxd_user_drv_remove(struct idxd_dev *idxd_dev) +{ + struct idxd_wq *wq = idxd_dev_to_wq(idxd_dev); + + mutex_lock(&wq->wq_lock); + idxd_wq_del_cdev(wq); + drv_disable_wq(wq); + wq->type = IDXD_WQT_NONE; + destroy_workqueue(wq->wq); + wq->wq = NULL; + mutex_unlock(&wq->wq_lock); +} + +static enum idxd_dev_type dev_types[] = { + IDXD_DEV_WQ, + IDXD_DEV_NONE, +}; + +struct idxd_device_driver idxd_user_drv = { + .probe = idxd_user_drv_probe, + .remove = idxd_user_drv_remove, + .name = "user", + .type = dev_types, +}; +EXPORT_SYMBOL_GPL(idxd_user_drv); + +int idxd_cdev_register(void) +{ + int rc, i; + + for (i = 0; i < IDXD_TYPE_MAX; i++) { + ida_init(&ictx[i].minor_ida); + rc = alloc_chrdev_region(&ictx[i].devt, 0, MINORMASK, + ictx[i].name); + if (rc) + goto err_free_chrdev_region; + } + + return 0; + +err_free_chrdev_region: + for (i--; i >= 0; i--) + unregister_chrdev_region(ictx[i].devt, MINORMASK); + + return rc; +} + +void idxd_cdev_remove(void) +{ + int i; + + for (i = 0; i < IDXD_TYPE_MAX; i++) { + unregister_chrdev_region(ictx[i].devt, MINORMASK); + ida_destroy(&ictx[i].minor_ida); + } +} + +/** + * idxd_copy_cr - copy completion record to user address space found by wq and + * PASID + * @wq: work queue + * @pasid: PASID + * @addr: user fault address to write + * @cr: completion record + * @len: number of bytes to copy + * + * This is called by a work that handles completion record fault. + * + * Return: number of bytes copied. + */ +int idxd_copy_cr(struct idxd_wq *wq, ioasid_t pasid, unsigned long addr, + void *cr, int len) +{ + struct device *dev = &wq->idxd->pdev->dev; + int left = len, status_size = 1; + struct idxd_user_context *ctx; + struct mm_struct *mm; + + mutex_lock(&wq->uc_lock); + + ctx = xa_load(&wq->upasid_xa, pasid); + if (!ctx) { + dev_warn(dev, "No user context\n"); + goto out; + } + + mm = ctx->mm; + /* + * The completion record fault handling work is running in kernel + * thread context. It temporarily switches to the mm to copy cr + * to addr in the mm. + */ + kthread_use_mm(mm); + left = copy_to_user((void __user *)addr + status_size, cr + status_size, + len - status_size); + /* + * Copy status only after the rest of completion record is copied + * successfully so that the user gets the complete completion record + * when a non-zero status is polled. + */ + if (!left) { + u8 status; + + /* + * Ensure that the completion record's status field is written + * after the rest of the completion record has been written. + * This ensures that the user receives the correct completion + * record information once polling for a non-zero status. + */ + wmb(); + status = *(u8 *)cr; + if (put_user(status, (u8 __user *)addr)) + left += status_size; + } else { + left += status_size; + } + kthread_unuse_mm(mm); + +out: + mutex_unlock(&wq->uc_lock); + + return len - left; +} |