[CI,2/3] drm/i915/gem: Extend mmap support for lmem
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Message ID 20200101163918.768253-2-chris@chris-wilson.co.uk
State New
Headers show
Series
  • [CI,1/3] drm/i915/gem: Single page objects are naturally contiguous
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Commit Message

Chris Wilson Jan. 1, 2020, 4:39 p.m. UTC
From: Abdiel Janulgue <abdiel.janulgue@linux.intel.com>

Local memory objects are similar to our usual scatterlist, but instead
of using the struct page stored therein, we need to use the
sg->dma_address.

Signed-off-by: Abdiel Janulgue <abdiel.janulgue@linux.intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/gem/i915_gem_mman.c | 16 +++++++------
 drivers/gpu/drm/i915/i915_drv.h          |  6 ++---
 drivers/gpu/drm/i915/i915_mm.c           | 30 +++++++++++++++---------
 3 files changed, 31 insertions(+), 21 deletions(-)

Patch
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diff --git a/drivers/gpu/drm/i915/gem/i915_gem_mman.c b/drivers/gpu/drm/i915/gem/i915_gem_mman.c
index ed0d9a2f0e7b..395cb407b7ae 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_mman.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_mman.c
@@ -217,6 +217,7 @@  static vm_fault_t i915_error_to_vmf_fault(int err)
 
 	case -ENOSPC: /* shmemfs allocation failure */
 	case -ENOMEM: /* our allocation failure */
+	case -ENXIO:
 		return VM_FAULT_OOM;
 
 	case 0:
@@ -237,11 +238,10 @@  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;
+	bool use_dma =
+		!i915_gem_object_type_has(obj, I915_GEM_OBJECT_HAS_STRUCT_PAGE);
 	int err;
 
-	if (unlikely(!i915_gem_object_has_struct_page(obj)))
-		return VM_FAULT_SIGBUS;
-
 	/* Sanity check that we allow writing into this object */
 	if (unlikely(i915_gem_object_is_readonly(obj) &&
 		     area->vm_flags & VM_WRITE))
@@ -252,9 +252,9 @@  static vm_fault_t vm_fault_cpu(struct vm_fault *vmf)
 		goto out;
 
 	/* PTEs are revoked in obj->ops->put_pages() */
-	err = remap_io_sg_page(area,
-			       area->vm_start, area->vm_end - area->vm_start,
-			       obj->mm.pages->sgl);
+	err = remap_io_sg(area,
+			  area->vm_start, area->vm_end - area->vm_start,
+			  obj->mm.pages->sgl, use_dma);
 
 	if (area->vm_flags & VM_WRITE) {
 		GEM_BUG_ON(!i915_gem_object_has_pinned_pages(obj));
@@ -553,7 +553,9 @@  __assign_mmap_offset(struct drm_file *file,
 	}
 
 	if (mmap_type != I915_MMAP_TYPE_GTT &&
-	    !i915_gem_object_has_struct_page(obj)) {
+	    !i915_gem_object_type_has(obj,
+				      I915_GEM_OBJECT_HAS_STRUCT_PAGE |
+				      I915_GEM_OBJECT_HAS_IOMEM)) {
 		err = -ENODEV;
 		goto out;
 	}
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 2ee9f57d165d..7491c903ced8 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -2027,9 +2027,9 @@  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);
+int remap_io_sg(struct vm_area_struct *vma,
+		unsigned long addr, unsigned long size,
+		struct scatterlist *sgl, bool use_dma);
 
 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 2998689e6d42..7f1680b4125e 100644
--- a/drivers/gpu/drm/i915/i915_mm.c
+++ b/drivers/gpu/drm/i915/i915_mm.c
@@ -35,6 +35,7 @@  struct remap_pfn {
 	pgprot_t prot;
 
 	struct sgt_iter sgt;
+	bool dma;
 };
 
 static int remap_pfn(pte_t *pte, unsigned long addr, void *data)
@@ -48,12 +49,15 @@  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)
+static inline unsigned long sgt_pfn(const struct sgt_iter *sgt, bool use_dma)
 {
+	if (use_dma)
+		return (sgt->dma + sgt->curr) >> PAGE_SHIFT;
+
 	return sgt->pfn + (sgt->curr >> PAGE_SHIFT);
 }
 
-static int remap_sg_page(pte_t *pte, unsigned long addr, void *data)
+static int remap_sg(pte_t *pte, unsigned long addr, void *data)
 {
 	struct remap_pfn *r = data;
 
@@ -62,12 +66,12 @@  static int remap_sg_page(pte_t *pte, unsigned long addr, void *data)
 
 	/* 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)));
+		   pte_mkspecial(pfn_pte(sgt_pfn(&r->sgt, r->dma), 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);
+		r->sgt = __sgt_iter(__sg_next(r->sgt.sgp), r->dma);
 
 	return 0;
 }
@@ -108,30 +112,34 @@  int remap_io_mapping(struct vm_area_struct *vma,
 }
 
 /**
- * remap_io_sg_page - remap an IO mapping to userspace
+ * remap_io_sg- 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
+ * @use_dma: Use stored dma address or pfn
  *
  *  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)
+int remap_io_sg(struct vm_area_struct *vma,
+		unsigned long addr, unsigned long size,
+		struct scatterlist *sgl, bool use_dma)
 {
 	struct remap_pfn r = {
 		.mm = vma->vm_mm,
 		.prot = vma->vm_page_prot,
-		.sgt = __sgt_iter(sgl, false),
+		.sgt = __sgt_iter(sgl, use_dma),
+		.dma = use_dma,
 	};
 	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 (!use_dma)
+		flush_cache_range(vma, addr, size);
+
+	err = apply_to_page_range(r.mm, addr, size, remap_sg, &r);
 	if (unlikely(err)) {
 		zap_vma_ptes(vma, addr, r.pfn << PAGE_SHIFT);
 		return err;