drivers/dma/idxd/cdev.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* Copyright(c) 2019 Intel Corporation. All rights rsvd. */
   3 #include <linux/init.h>
   4 #include <linux/kernel.h>
   5 #include <linux/module.h>
   6 #include <linux/pci.h>
   7 #include <linux/device.h>
   8 #include <linux/sched/task.h>
   9 #include <linux/intel-svm.h>
  10 #include <linux/io-64-nonatomic-lo-hi.h>
  11 #include <linux/cdev.h>
  12 #include <linux/fs.h>
  13 #include <linux/poll.h>
  14 #include <linux/iommu.h>
  15 #include <uapi/linux/idxd.h>
  16 #include "registers.h"
  17 #include "idxd.h"
  18
  19 struct idxd_cdev_context {
  20         const char *name;
  21         dev_t devt;
  22         struct ida minor_ida;
  23 };
  24
  25 /*
  26  * ictx is an array based off of accelerator types. enum idxd_type
  27  * is used as index
  28  */
  29 static struct idxd_cdev_context ictx[IDXD_TYPE_MAX] = {
  30         { .name = "dsa" },
  31         { .name = "iax" }
  32 };
  33
  34 struct idxd_user_context {
  35         struct idxd_wq *wq;
  36         struct task_struct *task;
  37         unsigned int pasid;
  38         unsigned int flags;
  39         struct iommu_sva *sva;
  40 };
  41
  42 static void idxd_cdev_dev_release(struct device *dev)
  43 {
  44         struct idxd_cdev *idxd_cdev = container_of(dev, struct idxd_cdev, dev);
  45         struct idxd_cdev_context *cdev_ctx;
  46         struct idxd_wq *wq = idxd_cdev->wq;
  47
  48         cdev_ctx = &ictx[wq->idxd->data->type];
  49         ida_simple_remove(&cdev_ctx->minor_ida, idxd_cdev->minor);
  50         kfree(idxd_cdev);
  51 }
  52
  53 static struct device_type idxd_cdev_device_type = {
  54         .name = "idxd_cdev",
  55         .release = idxd_cdev_dev_release,
  56 };
  57
  58 static inline struct idxd_cdev *inode_idxd_cdev(struct inode *inode)
  59 {
  60         struct cdev *cdev = inode->i_cdev;
  61
  62         return container_of(cdev, struct idxd_cdev, cdev);
  63 }
  64
  65 static inline struct idxd_wq *inode_wq(struct inode *inode)
  66 {
  67         struct idxd_cdev *idxd_cdev = inode_idxd_cdev(inode);
  68
  69         return idxd_cdev->wq;
  70 }
  71
  72 static int idxd_cdev_open(struct inode *inode, struct file *filp)
  73 {
  74         struct idxd_user_context *ctx;
  75         struct idxd_device *idxd;
  76         struct idxd_wq *wq;
  77         struct device *dev;
  78         int rc = 0;
  79         struct iommu_sva *sva;
  80         unsigned int pasid;
  81
  82         wq = inode_wq(inode);
  83         idxd = wq->idxd;
  84         dev = &idxd->pdev->dev;
  85
  86         dev_dbg(dev, "%s called: %d\n", __func__, idxd_wq_refcount(wq));
  87
  88         ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
  89         if (!ctx)
  90                 return -ENOMEM;
  91
  92         mutex_lock(&wq->wq_lock);
  93
  94         if (idxd_wq_refcount(wq) > 0 && wq_dedicated(wq)) {
  95                 rc = -EBUSY;
  96                 goto failed;
  97         }
  98
  99         ctx->wq = wq;
 100         filp->private_data = ctx;
 101
 102         if (device_pasid_enabled(idxd)) {
 103                 sva = iommu_sva_bind_device(dev, current->mm, NULL);
 104                 if (IS_ERR(sva)) {
 105                         rc = PTR_ERR(sva);
 106                         dev_err(dev, "pasid allocation failed: %d\n", rc);
 107                         goto failed;
 108                 }
 109
 110                 pasid = iommu_sva_get_pasid(sva);
 111                 if (pasid == IOMMU_PASID_INVALID) {
 112                         iommu_sva_unbind_device(sva);
 113                         goto failed;
 114                 }
 115
 116                 ctx->sva = sva;
 117                 ctx->pasid = pasid;
 118
 119                 if (wq_dedicated(wq)) {
 120                         rc = idxd_wq_set_pasid(wq, pasid);
 121                         if (rc < 0) {
 122                                 iommu_sva_unbind_device(sva);
 123                                 dev_err(dev, "wq set pasid failed: %d\n", rc);
 124                                 goto failed;
 125                         }
 126                 }
 127         }
 128
 129         idxd_wq_get(wq);
 130         mutex_unlock(&wq->wq_lock);
 131         return 0;
 132
 133  failed:
 134         mutex_unlock(&wq->wq_lock);
 135         kfree(ctx);
 136         return rc;
 137 }
 138
 139 static int idxd_cdev_release(struct inode *node, struct file *filep)
 140 {
 141         struct idxd_user_context *ctx = filep->private_data;
 142         struct idxd_wq *wq = ctx->wq;
 143         struct idxd_device *idxd = wq->idxd;
 144         struct device *dev = &idxd->pdev->dev;
 145         int rc;
 146
 147         dev_dbg(dev, "%s called\n", __func__);
 148         filep->private_data = NULL;
 149
 150         /* Wait for in-flight operations to complete. */
 151         if (wq_shared(wq)) {
 152                 idxd_device_drain_pasid(idxd, ctx->pasid);
 153         } else {
 154                 if (device_pasid_enabled(idxd)) {
 155                         /* The wq disable in the disable pasid function will drain the wq */
 156                         rc = idxd_wq_disable_pasid(wq);
 157                         if (rc < 0)
 158                                 dev_err(dev, "wq disable pasid failed.\n");
 159                 } else {
 160                         idxd_wq_drain(wq);
 161                 }
 162         }
 163
 164         if (ctx->sva)
 165                 iommu_sva_unbind_device(ctx->sva);
 166         kfree(ctx);
 167         mutex_lock(&wq->wq_lock);
 168         idxd_wq_put(wq);
 169         mutex_unlock(&wq->wq_lock);
 170         return 0;
 171 }
 172
 173 static int check_vma(struct idxd_wq *wq, struct vm_area_struct *vma,
 174                      const char *func)
 175 {
 176         struct device *dev = &wq->idxd->pdev->dev;
 177
 178         if ((vma->vm_end - vma->vm_start) > PAGE_SIZE) {
 179                 dev_info_ratelimited(dev,
 180                                      "%s: %s: mapping too large: %lu\n",
 181                                      current->comm, func,
 182                                      vma->vm_end - vma->vm_start);
 183                 return -EINVAL;
 184         }
 185
 186         return 0;
 187 }
 188
 189 static int idxd_cdev_mmap(struct file *filp, struct vm_area_struct *vma)
 190 {
 191         struct idxd_user_context *ctx = filp->private_data;
 192         struct idxd_wq *wq = ctx->wq;
 193         struct idxd_device *idxd = wq->idxd;
 194         struct pci_dev *pdev = idxd->pdev;
 195         phys_addr_t base = pci_resource_start(pdev, IDXD_WQ_BAR);
 196         unsigned long pfn;
 197         int rc;
 198
 199         dev_dbg(&pdev->dev, "%s called\n", __func__);
 200         rc = check_vma(wq, vma, __func__);
 201         if (rc < 0)
 202                 return rc;
 203
 204         vma->vm_flags |= VM_DONTCOPY;
 205         pfn = (base + idxd_get_wq_portal_full_offset(wq->id,
 206                                 IDXD_PORTAL_LIMITED)) >> PAGE_SHIFT;
 207         vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
 208         vma->vm_private_data = ctx;
 209
 210         return io_remap_pfn_range(vma, vma->vm_start, pfn, PAGE_SIZE,
 211                         vma->vm_page_prot);
 212 }
 213
 214 static __poll_t idxd_cdev_poll(struct file *filp,
 215                                struct poll_table_struct *wait)
 216 {
 217         struct idxd_user_context *ctx = filp->private_data;
 218         struct idxd_wq *wq = ctx->wq;
 219         struct idxd_device *idxd = wq->idxd;
 220         unsigned long flags;
 221         __poll_t out = 0;
 222
 223         poll_wait(filp, &wq->err_queue, wait);
 224         spin_lock_irqsave(&idxd->dev_lock, flags);
 225         if (idxd->sw_err.valid)
 226                 out = EPOLLIN | EPOLLRDNORM;
 227         spin_unlock_irqrestore(&idxd->dev_lock, flags);
 228
 229         return out;
 230 }
 231
 232 static const struct file_operations idxd_cdev_fops = {
 233         .owner = THIS_MODULE,
 234         .open = idxd_cdev_open,
 235         .release = idxd_cdev_release,
 236         .mmap = idxd_cdev_mmap,
 237         .poll = idxd_cdev_poll,
 238 };
 239
 240 int idxd_cdev_get_major(struct idxd_device *idxd)
 241 {
 242         return MAJOR(ictx[idxd->data->type].devt);
 243 }
 244
 245 int idxd_wq_add_cdev(struct idxd_wq *wq)
 246 {
 247         struct idxd_device *idxd = wq->idxd;
 248         struct idxd_cdev *idxd_cdev;
 249         struct cdev *cdev;
 250         struct device *dev;
 251         struct idxd_cdev_context *cdev_ctx;
 252         int rc, minor;
 253
 254         idxd_cdev = kzalloc(sizeof(*idxd_cdev), GFP_KERNEL);
 255         if (!idxd_cdev)
 256                 return -ENOMEM;
 257
 258         idxd_cdev->wq = wq;
 259         cdev = &idxd_cdev->cdev;
 260         dev = &idxd_cdev->dev;
 261         cdev_ctx = &ictx[wq->idxd->data->type];
 262         minor = ida_simple_get(&cdev_ctx->minor_ida, 0, MINORMASK, GFP_KERNEL);
 263         if (minor < 0) {
 264                 kfree(idxd_cdev);
 265                 return minor;
 266         }
 267         idxd_cdev->minor = minor;
 268
 269         device_initialize(dev);
 270         dev->parent = &wq->conf_dev;
 271         dev->bus = &dsa_bus_type;
 272         dev->type = &idxd_cdev_device_type;
 273         dev->devt = MKDEV(MAJOR(cdev_ctx->devt), minor);
 274
 275         rc = dev_set_name(dev, "%s/wq%u.%u", idxd->data->name_prefix, idxd->id, wq->id);
 276         if (rc < 0)
 277                 goto err;
 278
 279         wq->idxd_cdev = idxd_cdev;
 280         cdev_init(cdev, &idxd_cdev_fops);
 281         rc = cdev_device_add(cdev, dev);
 282         if (rc) {
 283                 dev_dbg(&wq->idxd->pdev->dev, "cdev_add failed: %d\n", rc);
 284                 goto err;
 285         }
 286
 287         return 0;
 288
 289  err:
 290         put_device(dev);
 291         wq->idxd_cdev = NULL;
 292         return rc;
 293 }
 294
 295 void idxd_wq_del_cdev(struct idxd_wq *wq)
 296 {
 297         struct idxd_cdev *idxd_cdev;
 298         struct idxd_cdev_context *cdev_ctx;
 299
 300         cdev_ctx = &ictx[wq->idxd->data->type];
 301         idxd_cdev = wq->idxd_cdev;
 302         wq->idxd_cdev = NULL;
 303         cdev_device_del(&idxd_cdev->cdev, &idxd_cdev->dev);
 304         put_device(&idxd_cdev->dev);
 305 }
 306
 307 int idxd_cdev_register(void)
 308 {
 309         int rc, i;
 310
 311         for (i = 0; i < IDXD_TYPE_MAX; i++) {
 312                 ida_init(&ictx[i].minor_ida);
 313                 rc = alloc_chrdev_region(&ictx[i].devt, 0, MINORMASK,
 314                                          ictx[i].name);
 315                 if (rc)
 316                         return rc;
 317         }
 318
 319         return 0;
 320 }
 321
 322 void idxd_cdev_remove(void)
 323 {
 324         int i;
 325
 326         for (i = 0; i < IDXD_TYPE_MAX; i++) {
 327                 unregister_chrdev_region(ictx[i].devt, MINORMASK);
 328                 ida_destroy(&ictx[i].minor_ida);
 329         }
 330 }