--- /dev/null
+/*
+ * Copyright © 2012-2014 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ *
+ */
+
+#include "drmP.h"
+#include "i915_drm.h"
+#include "i915_drv.h"
+#include "i915_trace.h"
+#include "intel_drv.h"
+#include <linux/mmu_context.h>
+#include <linux/mmu_notifier.h>
+#include <linux/mempolicy.h>
+#include <linux/swap.h>
+
+struct i915_mm_struct {
+ struct mm_struct *mm;
+ struct drm_device *dev;
+ struct i915_mmu_notifier *mn;
+ struct hlist_node node;
+ struct kref kref;
+ struct work_struct work;
+};
+
+#if defined(CONFIG_MMU_NOTIFIER)
+#include <linux/interval_tree.h>
+
+struct i915_mmu_notifier {
+ spinlock_t lock;
+ struct hlist_node node;
+ struct mmu_notifier mn;
+ struct rb_root objects;
+ struct list_head linear;
+ unsigned long serial;
+ bool has_linear;
+};
+
+struct i915_mmu_object {
+ struct i915_mmu_notifier *mn;
+ struct interval_tree_node it;
+ struct list_head link;
+ struct drm_i915_gem_object *obj;
+ bool is_linear;
+};
+
+static unsigned long cancel_userptr(struct drm_i915_gem_object *obj)
+{
+ struct drm_device *dev = obj->base.dev;
+ unsigned long end;
+
+ mutex_lock(&dev->struct_mutex);
+ /* Cancel any active worker and force us to re-evaluate gup */
+ obj->userptr.work = NULL;
+
+ if (obj->pages != NULL) {
+ struct drm_i915_private *dev_priv = to_i915(dev);
+ struct i915_vma *vma, *tmp;
+ bool was_interruptible;
+
+ was_interruptible = dev_priv->mm.interruptible;
+ dev_priv->mm.interruptible = false;
+
+ list_for_each_entry_safe(vma, tmp, &obj->vma_list, vma_link) {
+ int ret = i915_vma_unbind(vma);
+ WARN_ON(ret && ret != -EIO);
+ }
+ WARN_ON(i915_gem_object_put_pages(obj));
+
+ dev_priv->mm.interruptible = was_interruptible;
+ }
+
+ end = obj->userptr.ptr + obj->base.size;
+
+ drm_gem_object_unreference(&obj->base);
+ mutex_unlock(&dev->struct_mutex);
+
+ return end;
+}
+
+static void *invalidate_range__linear(struct i915_mmu_notifier *mn,
+ struct mm_struct *mm,
+ unsigned long start,
+ unsigned long end)
+{
+ struct i915_mmu_object *mo;
+ unsigned long serial;
+
+restart:
+ serial = mn->serial;
+ list_for_each_entry(mo, &mn->linear, link) {
+ struct drm_i915_gem_object *obj;
+
+ if (mo->it.last < start || mo->it.start > end)
+ continue;
+
+ obj = mo->obj;
+
+ if (!kref_get_unless_zero(&obj->base.refcount))
+ continue;
+
+ spin_unlock(&mn->lock);
+
+ cancel_userptr(obj);
+
+ spin_lock(&mn->lock);
+ if (serial != mn->serial)
+ goto restart;
+ }
+
+ return NULL;
+}
+
+static void i915_gem_userptr_mn_invalidate_range_start(struct mmu_notifier *_mn,
+ struct mm_struct *mm,
+ unsigned long start,
+ unsigned long end)
+{
+ struct i915_mmu_notifier *mn = container_of(_mn, struct i915_mmu_notifier, mn);
+ struct interval_tree_node *it = NULL;
+ unsigned long next = start;
+ unsigned long serial = 0;
+
+ end--; /* interval ranges are inclusive, but invalidate range is exclusive */
+ while (next < end) {
+ struct drm_i915_gem_object *obj = NULL;
+
+ spin_lock(&mn->lock);
+ if (mn->has_linear)
+ it = invalidate_range__linear(mn, mm, start, end);
+ else if (serial == mn->serial)
+ it = interval_tree_iter_next(it, next, end);
+ else
+ it = interval_tree_iter_first(&mn->objects, start, end);
+ if (it != NULL) {
+ obj = container_of(it, struct i915_mmu_object, it)->obj;
+
+ /* The mmu_object is released late when destroying the
+ * GEM object so it is entirely possible to gain a
+ * reference on an object in the process of being freed
+ * since our serialisation is via the spinlock and not
+ * the struct_mutex - and consequently use it after it
+ * is freed and then double free it.
+ */
+ if (!kref_get_unless_zero(&obj->base.refcount)) {
+ spin_unlock(&mn->lock);
+ serial = 0;
+ continue;
+ }
+
+ serial = mn->serial;
+ }
+ spin_unlock(&mn->lock);
+ if (obj == NULL)
+ return;
+
+ next = cancel_userptr(obj);
+ }
+}
+
+static const struct mmu_notifier_ops i915_gem_userptr_notifier = {
+ .invalidate_range_start = i915_gem_userptr_mn_invalidate_range_start,
+};
+
+static struct i915_mmu_notifier *
+i915_mmu_notifier_create(struct mm_struct *mm)
+{
+ struct i915_mmu_notifier *mn;
+ int ret;
+
+ mn = kmalloc(sizeof(*mn), GFP_KERNEL);
+ if (mn == NULL)
+ return ERR_PTR(-ENOMEM);
+
+ spin_lock_init(&mn->lock);
+ mn->mn.ops = &i915_gem_userptr_notifier;
+ mn->objects = RB_ROOT;
+ mn->serial = 1;
+ INIT_LIST_HEAD(&mn->linear);
+ mn->has_linear = false;
+
+ /* Protected by mmap_sem (write-lock) */
+ ret = __mmu_notifier_register(&mn->mn, mm);
+ if (ret) {
+ kfree(mn);
+ return ERR_PTR(ret);
+ }
+
+ return mn;
+}
+
+static void __i915_mmu_notifier_update_serial(struct i915_mmu_notifier *mn)
+{
+ if (++mn->serial == 0)
+ mn->serial = 1;
+}
+
+static int
+i915_mmu_notifier_add(struct drm_device *dev,
+ struct i915_mmu_notifier *mn,
+ struct i915_mmu_object *mo)
+{
+ struct interval_tree_node *it;
+ int ret;
+
+ ret = i915_mutex_lock_interruptible(dev);
+ if (ret)
+ return ret;
+
+ /* Make sure we drop the final active reference (and thereby
+ * remove the objects from the interval tree) before we do
+ * the check for overlapping objects.
+ */
+ i915_gem_retire_requests(dev);
+
+ spin_lock(&mn->lock);
+ it = interval_tree_iter_first(&mn->objects,
+ mo->it.start, mo->it.last);
+ if (it) {
+ struct drm_i915_gem_object *obj;
+
+ /* We only need to check the first object in the range as it
+ * either has cancelled gup work queued and we need to
+ * return back to the user to give time for the gup-workers
+ * to flush their object references upon which the object will
+ * be removed from the interval-tree, or the the range is
+ * still in use by another client and the overlap is invalid.
+ *
+ * If we do have an overlap, we cannot use the interval tree
+ * for fast range invalidation.
+ */
+
+ obj = container_of(it, struct i915_mmu_object, it)->obj;
+ if (!obj->userptr.workers)
+ mn->has_linear = mo->is_linear = true;
+ else
+ ret = -EAGAIN;
+ } else
+ interval_tree_insert(&mo->it, &mn->objects);
+
+ if (ret == 0) {
+ list_add(&mo->link, &mn->linear);
+ __i915_mmu_notifier_update_serial(mn);
+ }
+ spin_unlock(&mn->lock);
+ mutex_unlock(&dev->struct_mutex);
+
+ return ret;
+}
+
+static bool i915_mmu_notifier_has_linear(struct i915_mmu_notifier *mn)
+{
+ struct i915_mmu_object *mo;
+
+ list_for_each_entry(mo, &mn->linear, link)
+ if (mo->is_linear)
+ return true;
+
+ return false;
+}
+
+static void
+i915_mmu_notifier_del(struct i915_mmu_notifier *mn,
+ struct i915_mmu_object *mo)
+{
+ spin_lock(&mn->lock);
+ list_del(&mo->link);
+ if (mo->is_linear)
+ mn->has_linear = i915_mmu_notifier_has_linear(mn);
+ else
+ interval_tree_remove(&mo->it, &mn->objects);
+ __i915_mmu_notifier_update_serial(mn);
+ spin_unlock(&mn->lock);
+}
+
+static void
+i915_gem_userptr_release__mmu_notifier(struct drm_i915_gem_object *obj)
+{
+ struct i915_mmu_object *mo;
+
+ mo = obj->userptr.mmu_object;
+ if (mo == NULL)
+ return;
+
+ i915_mmu_notifier_del(mo->mn, mo);
+ kfree(mo);
+
+ obj->userptr.mmu_object = NULL;
+}
+
+static struct i915_mmu_notifier *
+i915_mmu_notifier_find(struct i915_mm_struct *mm)
+{
+ struct i915_mmu_notifier *mn = mm->mn;
+
+ mn = mm->mn;
+ if (mn)
+ return mn;
+
+ down_write(&mm->mm->mmap_sem);
+ mutex_lock(&to_i915(mm->dev)->mm_lock);
+ if ((mn = mm->mn) == NULL) {
+ mn = i915_mmu_notifier_create(mm->mm);
+ if (!IS_ERR(mn))
+ mm->mn = mn;
+ }
+ mutex_unlock(&to_i915(mm->dev)->mm_lock);
+ up_write(&mm->mm->mmap_sem);
+
+ return mn;
+}
+
+static int
+i915_gem_userptr_init__mmu_notifier(struct drm_i915_gem_object *obj,
+ unsigned flags)
+{
+ struct i915_mmu_notifier *mn;
+ struct i915_mmu_object *mo;
+ int ret;
+
+ if (flags & I915_USERPTR_UNSYNCHRONIZED)
+ return capable(CAP_SYS_ADMIN) ? 0 : -EPERM;
+
+ if (WARN_ON(obj->userptr.mm == NULL))
+ return -EINVAL;
+
+ mn = i915_mmu_notifier_find(obj->userptr.mm);
+ if (IS_ERR(mn))
+ return PTR_ERR(mn);
+
+ mo = kzalloc(sizeof(*mo), GFP_KERNEL);
+ if (mo == NULL)
+ return -ENOMEM;
+
+ mo->mn = mn;
+ mo->it.start = obj->userptr.ptr;
+ mo->it.last = mo->it.start + obj->base.size - 1;
+ mo->obj = obj;
+
+ ret = i915_mmu_notifier_add(obj->base.dev, mn, mo);
+ if (ret) {
+ kfree(mo);
+ return ret;
+ }
+
+ obj->userptr.mmu_object = mo;
+ return 0;
+}
+
+static void
+i915_mmu_notifier_free(struct i915_mmu_notifier *mn,
+ struct mm_struct *mm)
+{
+ if (mn == NULL)
+ return;
+
+ mmu_notifier_unregister(&mn->mn, mm);
+ kfree(mn);
+}
+
+#else
+
+static void
+i915_gem_userptr_release__mmu_notifier(struct drm_i915_gem_object *obj)
+{
+}
+
+static int
+i915_gem_userptr_init__mmu_notifier(struct drm_i915_gem_object *obj,
+ unsigned flags)
+{
+ if ((flags & I915_USERPTR_UNSYNCHRONIZED) == 0)
+ return -ENODEV;
+
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ return 0;
+}
+
+static void
+i915_mmu_notifier_free(struct i915_mmu_notifier *mn,
+ struct mm_struct *mm)
+{
+}
+
+#endif
+
+static struct i915_mm_struct *
+__i915_mm_struct_find(struct drm_i915_private *dev_priv, struct mm_struct *real)
+{
+ struct i915_mm_struct *mm;
+
+ /* Protected by dev_priv->mm_lock */
+ hash_for_each_possible(dev_priv->mm_structs, mm, node, (unsigned long)real)
+ if (mm->mm == real)
+ return mm;
+
+ return NULL;
+}
+
+static int
+i915_gem_userptr_init__mm_struct(struct drm_i915_gem_object *obj)
+{
+ struct drm_i915_private *dev_priv = to_i915(obj->base.dev);
+ struct i915_mm_struct *mm;
+ int ret = 0;
+
+ /* During release of the GEM object we hold the struct_mutex. This
+ * precludes us from calling mmput() at that time as that may be
+ * the last reference and so call exit_mmap(). exit_mmap() will
+ * attempt to reap the vma, and if we were holding a GTT mmap
+ * would then call drm_gem_vm_close() and attempt to reacquire
+ * the struct mutex. So in order to avoid that recursion, we have
+ * to defer releasing the mm reference until after we drop the
+ * struct_mutex, i.e. we need to schedule a worker to do the clean
+ * up.
+ */
+ mutex_lock(&dev_priv->mm_lock);
+ mm = __i915_mm_struct_find(dev_priv, current->mm);
+ if (mm == NULL) {
+ mm = kmalloc(sizeof(*mm), GFP_KERNEL);
+ if (mm == NULL) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ kref_init(&mm->kref);
+ mm->dev = obj->base.dev;
+
+ mm->mm = current->mm;
+ atomic_inc(¤t->mm->mm_count);
+
+ mm->mn = NULL;
+
+ /* Protected by dev_priv->mm_lock */
+ hash_add(dev_priv->mm_structs,
+ &mm->node, (unsigned long)mm->mm);
+ } else
+ kref_get(&mm->kref);
+
+ obj->userptr.mm = mm;
+out:
+ mutex_unlock(&dev_priv->mm_lock);
+ return ret;
+}
+
+static void
+__i915_mm_struct_free__worker(struct work_struct *work)
+{
+ struct i915_mm_struct *mm = container_of(work, typeof(*mm), work);
+ i915_mmu_notifier_free(mm->mn, mm->mm);
+ mmdrop(mm->mm);
+ kfree(mm);
+}
+
+static void
+__i915_mm_struct_free(struct kref *kref)
+{
+ struct i915_mm_struct *mm = container_of(kref, typeof(*mm), kref);
+
+ /* Protected by dev_priv->mm_lock */
+ hash_del(&mm->node);
+ mutex_unlock(&to_i915(mm->dev)->mm_lock);
+
+ INIT_WORK(&mm->work, __i915_mm_struct_free__worker);
+ schedule_work(&mm->work);
+}
+
+static void
+i915_gem_userptr_release__mm_struct(struct drm_i915_gem_object *obj)
+{
+ if (obj->userptr.mm == NULL)
+ return;
+
+ kref_put_mutex(&obj->userptr.mm->kref,
+ __i915_mm_struct_free,
+ &to_i915(obj->base.dev)->mm_lock);
+ obj->userptr.mm = NULL;
+}
+
+struct get_pages_work {
+ struct work_struct work;
+ struct drm_i915_gem_object *obj;
+ struct task_struct *task;
+};
+
+#if IS_ENABLED(CONFIG_SWIOTLB)
+#define swiotlb_active() swiotlb_nr_tbl()
+#else
+#define swiotlb_active() 0
+#endif
+
+static int
+st_set_pages(struct sg_table **st, struct page **pvec, int num_pages)
+{
+ struct scatterlist *sg;
+ int ret, n;
+
+ *st = kmalloc(sizeof(**st), GFP_KERNEL);
+ if (*st == NULL)
+ return -ENOMEM;
+
+ if (swiotlb_active()) {
+ ret = sg_alloc_table(*st, num_pages, GFP_KERNEL);
+ if (ret)
+ goto err;
+
+ for_each_sg((*st)->sgl, sg, num_pages, n)
+ sg_set_page(sg, pvec[n], PAGE_SIZE, 0);
+ } else {
+ ret = sg_alloc_table_from_pages(*st, pvec, num_pages,
+ 0, num_pages << PAGE_SHIFT,
+ GFP_KERNEL);
+ if (ret)
+ goto err;
+ }
+
+ return 0;
+
+err:
+ kfree(*st);
+ *st = NULL;
+ return ret;
+}
+
+static void
+__i915_gem_userptr_get_pages_worker(struct work_struct *_work)
+{
+ struct get_pages_work *work = container_of(_work, typeof(*work), work);
+ struct drm_i915_gem_object *obj = work->obj;
+ struct drm_device *dev = obj->base.dev;
+ const int num_pages = obj->base.size >> PAGE_SHIFT;
+ struct page **pvec;
+ int pinned, ret;
+
+ ret = -ENOMEM;
+ pinned = 0;
+
+ pvec = kmalloc(num_pages*sizeof(struct page *),
+ GFP_TEMPORARY | __GFP_NOWARN | __GFP_NORETRY);
+ if (pvec == NULL)
+ pvec = drm_malloc_ab(num_pages, sizeof(struct page *));
+ if (pvec != NULL) {
+ struct mm_struct *mm = obj->userptr.mm->mm;
+
+ down_read(&mm->mmap_sem);
+ while (pinned < num_pages) {
+ ret = get_user_pages(work->task, mm,
+ obj->userptr.ptr + pinned * PAGE_SIZE,
+ num_pages - pinned,
+ !obj->userptr.read_only, 0,
+ pvec + pinned, NULL);
+ if (ret < 0)
+ break;
+
+ pinned += ret;
+ }
+ up_read(&mm->mmap_sem);
+ }
+
+ mutex_lock(&dev->struct_mutex);
+ if (obj->userptr.work != &work->work) {
+ ret = 0;
+ } else if (pinned == num_pages) {
+ ret = st_set_pages(&obj->pages, pvec, num_pages);
+ if (ret == 0) {
+ list_add_tail(&obj->global_list, &to_i915(dev)->mm.unbound_list);
+ pinned = 0;
+ }
+ }
+
+ obj->userptr.work = ERR_PTR(ret);
+ obj->userptr.workers--;
+ drm_gem_object_unreference(&obj->base);
+ mutex_unlock(&dev->struct_mutex);
+
+ release_pages(pvec, pinned, 0);
+ drm_free_large(pvec);
+
+ put_task_struct(work->task);
+ kfree(work);
+}
+
+static int
+i915_gem_userptr_get_pages(struct drm_i915_gem_object *obj)
+{
+ const int num_pages = obj->base.size >> PAGE_SHIFT;
+ struct page **pvec;
+ int pinned, ret;
+
+ /* If userspace should engineer that these pages are replaced in
+ * the vma between us binding this page into the GTT and completion
+ * of rendering... Their loss. If they change the mapping of their
+ * pages they need to create a new bo to point to the new vma.
+ *
+ * However, that still leaves open the possibility of the vma
+ * being copied upon fork. Which falls under the same userspace
+ * synchronisation issue as a regular bo, except that this time
+ * the process may not be expecting that a particular piece of
+ * memory is tied to the GPU.
+ *
+ * Fortunately, we can hook into the mmu_notifier in order to
+ * discard the page references prior to anything nasty happening
+ * to the vma (discard or cloning) which should prevent the more
+ * egregious cases from causing harm.
+ */
+
+ pvec = NULL;
+ pinned = 0;
+ if (obj->userptr.mm->mm == current->mm) {
+ pvec = kmalloc(num_pages*sizeof(struct page *),
+ GFP_TEMPORARY | __GFP_NOWARN | __GFP_NORETRY);
+ if (pvec == NULL) {
+ pvec = drm_malloc_ab(num_pages, sizeof(struct page *));
+ if (pvec == NULL)
+ return -ENOMEM;
+ }
+
+ pinned = __get_user_pages_fast(obj->userptr.ptr, num_pages,
+ !obj->userptr.read_only, pvec);
+ }
+ if (pinned < num_pages) {
+ if (pinned < 0) {
+ ret = pinned;
+ pinned = 0;
+ } else {
+ /* Spawn a worker so that we can acquire the
+ * user pages without holding our mutex. Access
+ * to the user pages requires mmap_sem, and we have
+ * a strict lock ordering of mmap_sem, struct_mutex -
+ * we already hold struct_mutex here and so cannot
+ * call gup without encountering a lock inversion.
+ *
+ * Userspace will keep on repeating the operation
+ * (thanks to EAGAIN) until either we hit the fast
+ * path or the worker completes. If the worker is
+ * cancelled or superseded, the task is still run
+ * but the results ignored. (This leads to
+ * complications that we may have a stray object
+ * refcount that we need to be wary of when
+ * checking for existing objects during creation.)
+ * If the worker encounters an error, it reports
+ * that error back to this function through
+ * obj->userptr.work = ERR_PTR.
+ */
+ ret = -EAGAIN;
+ if (obj->userptr.work == NULL &&
+ obj->userptr.workers < I915_GEM_USERPTR_MAX_WORKERS) {
+ struct get_pages_work *work;
+
+ work = kmalloc(sizeof(*work), GFP_KERNEL);
+ if (work != NULL) {
+ obj->userptr.work = &work->work;
+ obj->userptr.workers++;
+
+ work->obj = obj;
+ drm_gem_object_reference(&obj->base);
+
+ work->task = current;
+ get_task_struct(work->task);
+
+ INIT_WORK(&work->work, __i915_gem_userptr_get_pages_worker);
+ schedule_work(&work->work);
+ } else
+ ret = -ENOMEM;
+ } else {
+ if (IS_ERR(obj->userptr.work)) {
+ ret = PTR_ERR(obj->userptr.work);
+ obj->userptr.work = NULL;
+ }
+ }
+ }
+ } else {
+ ret = st_set_pages(&obj->pages, pvec, num_pages);
+ if (ret == 0) {
+ obj->userptr.work = NULL;
+ pinned = 0;
+ }
+ }
+
+ release_pages(pvec, pinned, 0);
+ drm_free_large(pvec);
+ return ret;
+}
+
+static void
+i915_gem_userptr_put_pages(struct drm_i915_gem_object *obj)
+{
+ struct sg_page_iter sg_iter;
+
+ BUG_ON(obj->userptr.work != NULL);
+
+ if (obj->madv != I915_MADV_WILLNEED)
+ obj->dirty = 0;
+
+ for_each_sg_page(obj->pages->sgl, &sg_iter, obj->pages->nents, 0) {
+ struct page *page = sg_page_iter_page(&sg_iter);
+
+ if (obj->dirty)
+ set_page_dirty(page);
+
+ mark_page_accessed(page);
+ page_cache_release(page);
+ }
+ obj->dirty = 0;
+
+ sg_free_table(obj->pages);
+ kfree(obj->pages);
+}
+
+static void
+i915_gem_userptr_release(struct drm_i915_gem_object *obj)
+{
+ i915_gem_userptr_release__mmu_notifier(obj);
+ i915_gem_userptr_release__mm_struct(obj);
+}
+
+static int
+i915_gem_userptr_dmabuf_export(struct drm_i915_gem_object *obj)
+{
+ if (obj->userptr.mmu_object)
+ return 0;
+
+ return i915_gem_userptr_init__mmu_notifier(obj, 0);
+}
+
+static const struct drm_i915_gem_object_ops i915_gem_userptr_ops = {
+ .dmabuf_export = i915_gem_userptr_dmabuf_export,
+ .get_pages = i915_gem_userptr_get_pages,
+ .put_pages = i915_gem_userptr_put_pages,
+ .release = i915_gem_userptr_release,
+};
+
+/**
+ * Creates a new mm object that wraps some normal memory from the process
+ * context - user memory.
+ *
+ * We impose several restrictions upon the memory being mapped
+ * into the GPU.
+ * 1. It must be page aligned (both start/end addresses, i.e ptr and size).
+ * 2. It must be normal system memory, not a pointer into another map of IO
+ * space (e.g. it must not be a GTT mmapping of another object).
+ * 3. We only allow a bo as large as we could in theory map into the GTT,
+ * that is we limit the size to the total size of the GTT.
+ * 4. The bo is marked as being snoopable. The backing pages are left
+ * accessible directly by the CPU, but reads and writes by the GPU may
+ * incur the cost of a snoop (unless you have an LLC architecture).
+ *
+ * Synchronisation between multiple users and the GPU is left to userspace
+ * through the normal set-domain-ioctl. The kernel will enforce that the
+ * GPU relinquishes the VMA before it is returned back to the system
+ * i.e. upon free(), munmap() or process termination. However, the userspace
+ * malloc() library may not immediately relinquish the VMA after free() and
+ * instead reuse it whilst the GPU is still reading and writing to the VMA.
+ * Caveat emptor.
+ *
+ * Also note, that the object created here is not currently a "first class"
+ * object, in that several ioctls are banned. These are the CPU access
+ * ioctls: mmap(), pwrite and pread. In practice, you are expected to use
+ * direct access via your pointer rather than use those ioctls.
+ *
+ * If you think this is a good interface to use to pass GPU memory between
+ * drivers, please use dma-buf instead. In fact, wherever possible use
+ * dma-buf instead.
+ */
+int
+i915_gem_userptr_ioctl(struct drm_device *dev, void *data, struct drm_file *file)
+{
+ struct drm_i915_private *dev_priv = dev->dev_private;
+ struct drm_i915_gem_userptr *args = data;
+ struct drm_i915_gem_object *obj;
+ int ret;
+ u32 handle;
+
+ if (args->flags & ~(I915_USERPTR_READ_ONLY |
+ I915_USERPTR_UNSYNCHRONIZED))
+ return -EINVAL;
+
+ if (offset_in_page(args->user_ptr | args->user_size))
+ return -EINVAL;
+
+ if (args->user_size > dev_priv->gtt.base.total)
+ return -E2BIG;
+
+ if (!access_ok(args->flags & I915_USERPTR_READ_ONLY ? VERIFY_READ : VERIFY_WRITE,
+ (char __user *)(unsigned long)args->user_ptr, args->user_size))
+ return -EFAULT;
+
+ if (args->flags & I915_USERPTR_READ_ONLY) {
+ /* On almost all of the current hw, we cannot tell the GPU that a
+ * page is readonly, so this is just a placeholder in the uAPI.
+ */
+ return -ENODEV;
+ }
+
+ obj = i915_gem_object_alloc(dev);
+ if (obj == NULL)
+ return -ENOMEM;
+
+ drm_gem_private_object_init(dev, &obj->base, args->user_size);
+ i915_gem_object_init(obj, &i915_gem_userptr_ops);
+ obj->cache_level = I915_CACHE_LLC;
+ obj->base.write_domain = I915_GEM_DOMAIN_CPU;
+ obj->base.read_domains = I915_GEM_DOMAIN_CPU;
+
+ obj->userptr.ptr = args->user_ptr;
+ obj->userptr.read_only = !!(args->flags & I915_USERPTR_READ_ONLY);
+
+ /* And keep a pointer to the current->mm for resolving the user pages
+ * at binding. This means that we need to hook into the mmu_notifier
+ * in order to detect if the mmu is destroyed.
+ */
+ ret = i915_gem_userptr_init__mm_struct(obj);
+ if (ret == 0)
+ ret = i915_gem_userptr_init__mmu_notifier(obj, args->flags);
+ if (ret == 0)
+ ret = drm_gem_handle_create(file, &obj->base, &handle);
+
+ /* drop reference from allocate - handle holds it now */
+ drm_gem_object_unreference_unlocked(&obj->base);
+ if (ret)
+ return ret;
+
+ args->handle = handle;
+ return 0;
+}
+
+int
+i915_gem_init_userptr(struct drm_device *dev)
+{
+ struct drm_i915_private *dev_priv = to_i915(dev);
+ mutex_init(&dev_priv->mm_lock);
+ hash_init(dev_priv->mm_structs);
+ return 0;
+}
Code Review / kvmfornfv.git / blobdiff