From 82b926450951f8e3cf5931ae3d4bbb55f7ed17bd Mon Sep 17 00:00:00 2001
From: Abdiel Janulgue <abdiel.janulgue@linux.intel.com>
Date: Tue, 31 Dec 2019 20:03:56 +0000
Subject: drm/i915: Introduce remap_io_sg() to prefault discontiguous objects
Git-commit: 1764b992be0f1c4295d2d9572ec46d568bd3fc14
Patch-mainline: v5.6-rc1
References: jsc#SLE-12680, jsc#SLE-12880, jsc#SLE-12882, jsc#SLE-12883, jsc#SLE-13496, jsc#SLE-15322
Provide a way to set the PTE within apply_page_range for discontiguous
objects in addition to the existing method of just incrementing the pfn
for a page range.
Fixes: cc662126b413 ("drm/i915: Introduce DRM_I915_GEM_MMAP_OFFSET")
Signed-off-by: Abdiel Janulgue <abdiel.janulgue@linux.intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Matthew Auld <matthew.auld@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20191231200356.409475-1-chris@chris-wilson.co.uk
Signed-off-by: Patrik Jakobsson <pjakobsson@suse.de>
---
drivers/gpu/drm/i915/gem/i915_gem_mman.c | 32 +++++--------
drivers/gpu/drm/i915/i915_drv.h | 3 ++
drivers/gpu/drm/i915/i915_mm.c | 59 ++++++++++++++++++++++++
3 files changed, 74 insertions(+), 20 deletions(-)
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_mman.c b/drivers/gpu/drm/i915/gem/i915_gem_mman.c
index 879fff8adc48..905527ce2999 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_mman.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_mman.c
@@ -236,42 +236,34 @@ static vm_fault_t vm_fault_cpu(struct vm_fault *vmf)
struct vm_area_struct *area = vmf->vma;
struct i915_mmap_offset *mmo = area->vm_private_data;
struct drm_i915_gem_object *obj = mmo->obj;
- unsigned long i, size = area->vm_end - area->vm_start;
- bool write = area->vm_flags & VM_WRITE;
- vm_fault_t ret = VM_FAULT_SIGBUS;
int err;
- if (!i915_gem_object_has_struct_page(obj))
- return ret;
+ if (unlikely(!i915_gem_object_has_struct_page(obj)))
+ return VM_FAULT_SIGBUS;
/* Sanity check that we allow writing into this object */
- if (i915_gem_object_is_readonly(obj) && write)
- return ret;
+ if (unlikely(i915_gem_object_is_readonly(obj) &&
+ area->vm_flags & VM_WRITE))
+ return VM_FAULT_SIGBUS;
err = i915_gem_object_pin_pages(obj);
if (err)
- return i915_error_to_vmf_fault(err);
+ goto out;
/* PTEs are revoked in obj->ops->put_pages() */
- for (i = 0; i < size >> PAGE_SHIFT; i++) {
- struct page *page = i915_gem_object_get_page(obj, i);
-
- ret = vmf_insert_pfn(area,
- (unsigned long)area->vm_start + i * PAGE_SIZE,
- page_to_pfn(page));
- if (ret != VM_FAULT_NOPAGE)
- break;
- }
+ err = remap_io_sg_page(area,
+ area->vm_start, area->vm_end - area->vm_start,
+ obj->mm.pages->sgl);
- if (write) {
+ if (area->vm_flags & VM_WRITE) {
GEM_BUG_ON(!i915_gem_object_has_pinned_pages(obj));
- obj->cache_dirty = true; /* XXX flush after PAT update? */
obj->mm.dirty = true;
}
i915_gem_object_unpin_pages(obj);
- return ret;
+out:
+ return i915_error_to_vmf_fault(err);
}
static vm_fault_t vm_fault_gtt(struct vm_fault *vmf)
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index f8fead18cac5..2c7e3020e766 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -2017,6 +2017,9 @@ int i915_reg_read_ioctl(struct drm_device *dev, void *data,
int remap_io_mapping(struct vm_area_struct *vma,
unsigned long addr, unsigned long pfn, unsigned long size,
struct io_mapping *iomap);
+int remap_io_sg_page(struct vm_area_struct *vma,
+ unsigned long addr, unsigned long size,
+ struct scatterlist *sgl);
static inline int intel_hws_csb_write_index(struct drm_i915_private *i915)
{
diff --git a/drivers/gpu/drm/i915/i915_mm.c b/drivers/gpu/drm/i915/i915_mm.c
index 318562ce64c0..2998689e6d42 100644
--- a/drivers/gpu/drm/i915/i915_mm.c
+++ b/drivers/gpu/drm/i915/i915_mm.c
@@ -33,6 +33,8 @@ struct remap_pfn {
struct mm_struct *mm;
unsigned long pfn;
pgprot_t prot;
+
+ struct sgt_iter sgt;
};
static int remap_pfn(pte_t *pte, unsigned long addr, void *data)
@@ -46,6 +48,30 @@ static int remap_pfn(pte_t *pte, unsigned long addr, void *data)
return 0;
}
+static inline unsigned long sgt_pfn(const struct sgt_iter *sgt)
+{
+ return sgt->pfn + (sgt->curr >> PAGE_SHIFT);
+}
+
+static int remap_sg_page(pte_t *pte, unsigned long addr, void *data)
+{
+ struct remap_pfn *r = data;
+
+ if (GEM_WARN_ON(!r->sgt.pfn))
+ return -EINVAL;
+
+ /* Special PTE are not associated with any struct page */
+ set_pte_at(r->mm, addr, pte,
+ pte_mkspecial(pfn_pte(sgt_pfn(&r->sgt), r->prot)));
+ r->pfn++; /* track insertions in case we need to unwind later */
+
+ r->sgt.curr += PAGE_SIZE;
+ if (r->sgt.curr >= r->sgt.max)
+ r->sgt = __sgt_iter(__sg_next(r->sgt.sgp), false);
+
+ return 0;
+}
+
/**
* remap_io_mapping - remap an IO mapping to userspace
* @vma: user vma to map to
@@ -80,3 +106,36 @@ int remap_io_mapping(struct vm_area_struct *vma,
return 0;
}
+
+/**
+ * remap_io_sg_page - remap an IO mapping to userspace
+ * @vma: user vma to map to
+ * @addr: target user address to start at
+ * @size: size of map area
+ * @sgl: Start sg entry
+ *
+ * Note: this is only safe if the mm semaphore is held when called.
+ */
+int remap_io_sg_page(struct vm_area_struct *vma,
+ unsigned long addr, unsigned long size,
+ struct scatterlist *sgl)
+{
+ struct remap_pfn r = {
+ .mm = vma->vm_mm,
+ .prot = vma->vm_page_prot,
+ .sgt = __sgt_iter(sgl, false),
+ };
+ int err;
+
+ /* We rely on prevalidation of the io-mapping to skip track_pfn(). */
+ GEM_BUG_ON((vma->vm_flags & EXPECTED_FLAGS) != EXPECTED_FLAGS);
+
+ flush_cache_range(vma, addr, size);
+ err = apply_to_page_range(r.mm, addr, size, remap_sg_page, &r);
+ if (unlikely(err)) {
+ zap_vma_ptes(vma, addr, r.pfn << PAGE_SHIFT);
+ return err;
+ }
+
+ return 0;
+}
--
2.28.0