drm/i915/gen8: Abstract PDP usage

Up until now, ppgtt->pdp has always been the root of our page tables.
Legacy 32b addresses acted like it had 1 PDP with 4 PDPEs.

In preparation for 4 level page tables, we need to stop using ppgtt->pdp
directly unless we know it's what we want. The future structure will use
ppgtt->pml4 for the top level, and the pdp is just one of the entries
being pointed to by a pml4e. The temporal pdp local variable will be
removed once the rest of the 4-level code lands.

Also, start passing the vm pointer to the alloc functions, instead of
ppgtt.

v2: Updated after dynamic page allocation changes.
v3: Rebase after s/page_tables/page_table/.
v4: Rebase after changes in "Dynamic page table allocations" patch.
v5: Rebase after Mika's ppgtt cleanup / scratch merge patch series.
v6: Rebase after final merged version of Mika's ppgtt/scratch patches.
v7: Keep pagetable map in-line (and avoid unnecessary for_each_pde
loops), remove redundant ppgtt pointer in _alloc_pagetabs (Akash)
v8: Fix text indentation in _alloc_pagetabs/page_directories (Chris)
v9: Defer gen8_alloc_va_range_4lvl definition until 4lvl is implemented,
clean-up gen8_ppgtt_cleanup [pun intended] (Akash).
v10: Clean-up commit message (Akash).

Cc: Akash Goel <akash.goel@intel.com>
Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Michel Thierry <michel.thierry@intel.com> (v2+)
Reviewed-by: "Akash Goel" <akash.goel@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_gem_gtt.c

@@ -607,6 +607,7 @@ static void gen8_ppgtt_clear_range(struct i915_address_space *vm,
 {
 	struct i915_hw_ppgtt *ppgtt =
 		container_of(vm, struct i915_hw_ppgtt, base);
+	struct i915_page_directory_pointer *pdp = &ppgtt->pdp; /* FIXME: 48b */
 	gen8_pte_t *pt_vaddr, scratch_pte;
 	unsigned pdpe = start >> GEN8_PDPE_SHIFT & GEN8_PDPE_MASK;
 	unsigned pde = start >> GEN8_PDE_SHIFT & GEN8_PDE_MASK;
@@ -621,10 +622,10 @@ static void gen8_ppgtt_clear_range(struct i915_address_space *vm,
 		struct i915_page_directory *pd;
 		struct i915_page_table *pt;
 
-		if (WARN_ON(!ppgtt->pdp.page_directory[pdpe]))
+		if (WARN_ON(!pdp->page_directory[pdpe]))
 			break;
 
-		pd = ppgtt->pdp.page_directory[pdpe];
+		pd = pdp->page_directory[pdpe];
 
 		if (WARN_ON(!pd->page_table[pde]))
 			break;
@@ -662,6 +663,7 @@ static void gen8_ppgtt_insert_entries(struct i915_address_space *vm,
 {
 	struct i915_hw_ppgtt *ppgtt =
 		container_of(vm, struct i915_hw_ppgtt, base);
+	struct i915_page_directory_pointer *pdp = &ppgtt->pdp; /* FIXME: 48b */
 	gen8_pte_t *pt_vaddr;
 	unsigned pdpe = start >> GEN8_PDPE_SHIFT & GEN8_PDPE_MASK;
 	unsigned pde = start >> GEN8_PDE_SHIFT & GEN8_PDE_MASK;
@@ -675,7 +677,7 @@ static void gen8_ppgtt_insert_entries(struct i915_address_space *vm,
 			break;
 
 		if (pt_vaddr == NULL) {
-			struct i915_page_directory *pd = ppgtt->pdp.page_directory[pdpe];
+			struct i915_page_directory *pd = pdp->page_directory[pdpe];
 			struct i915_page_table *pt = pd->page_table[pde];
 			pt_vaddr = kmap_px(pt);
 		}
@@ -755,28 +757,29 @@ static void gen8_ppgtt_cleanup(struct i915_address_space *vm)
 {
 	struct i915_hw_ppgtt *ppgtt =
 		container_of(vm, struct i915_hw_ppgtt, base);
+	struct i915_page_directory_pointer *pdp = &ppgtt->pdp; /* FIXME: 48b */
+	struct drm_device *dev = ppgtt->base.dev;
 	int i;
 
-	for_each_set_bit(i, ppgtt->pdp.used_pdpes,
-			 I915_PDPES_PER_PDP(ppgtt->base.dev)) {
-		if (WARN_ON(!ppgtt->pdp.page_directory[i]))
+	for_each_set_bit(i, pdp->used_pdpes, I915_PDPES_PER_PDP(dev)) {
+		if (WARN_ON(!pdp->page_directory[i]))
 			continue;
 
-		gen8_free_page_tables(ppgtt->base.dev,
-				      ppgtt->pdp.page_directory[i]);
-		free_pd(ppgtt->base.dev, ppgtt->pdp.page_directory[i]);
+		gen8_free_page_tables(dev, pdp->page_directory[i]);
+		free_pd(dev, pdp->page_directory[i]);
 	}
 
-	free_pdp(ppgtt->base.dev, &ppgtt->pdp);
+	free_pdp(dev, pdp);
+
 	gen8_free_scratch(vm);
 }
 
 /**
  * gen8_ppgtt_alloc_pagetabs() - Allocate page tables for VA range.
- * @ppgtt:	Master ppgtt structure.
- * @pd:		Page directory for this address range.
+ * @vm:	Master vm structure.
+ * @pd:	Page directory for this address range.
  * @start:	Starting virtual address to begin allocations.
- * @length	Size of the allocations.
+ * @length:	Size of the allocations.
  * @new_pts:	Bitmap set by function with new allocations. Likely used by the
  *		caller to free on error.
  *
@@ -789,13 +792,13 @@ static void gen8_ppgtt_cleanup(struct i915_address_space *vm)
  *
  * Return: 0 if success; negative error code otherwise.
  */
-static int gen8_ppgtt_alloc_pagetabs(struct i915_hw_ppgtt *ppgtt,
+static int gen8_ppgtt_alloc_pagetabs(struct i915_address_space *vm,
 				     struct i915_page_directory *pd,
 				     uint64_t start,
 				     uint64_t length,
 				     unsigned long *new_pts)
 {
-	struct drm_device *dev = ppgtt->base.dev;
+	struct drm_device *dev = vm->dev;
 	struct i915_page_table *pt;
 	uint64_t temp;
 	uint32_t pde;
@@ -804,7 +807,7 @@ static int gen8_ppgtt_alloc_pagetabs(struct i915_hw_ppgtt *ppgtt,
 		/* Don't reallocate page tables */
 		if (test_bit(pde, pd->used_pdes)) {
 			/* Scratch is never allocated this way */
-			WARN_ON(pt == ppgtt->base.scratch_pt);
+			WARN_ON(pt == vm->scratch_pt);
 			continue;
 		}
 
@@ -812,7 +815,7 @@ static int gen8_ppgtt_alloc_pagetabs(struct i915_hw_ppgtt *ppgtt,
 		if (IS_ERR(pt))
 			goto unwind_out;
 
-		gen8_initialize_pt(&ppgtt->base, pt);
+		gen8_initialize_pt(vm, pt);
 		pd->page_table[pde] = pt;
 		__set_bit(pde, new_pts);
 	}
@@ -828,11 +831,11 @@ unwind_out:
 
 /**
  * gen8_ppgtt_alloc_page_directories() - Allocate page directories for VA range.
- * @ppgtt:	Master ppgtt structure.
+ * @vm:	Master vm structure.
  * @pdp:	Page directory pointer for this address range.
  * @start:	Starting virtual address to begin allocations.
- * @length	Size of the allocations.
- * @new_pds	Bitmap set by function with new allocations. Likely used by the
+ * @length:	Size of the allocations.
+ * @new_pds:	Bitmap set by function with new allocations. Likely used by the
  *		caller to free on error.
  *
  * Allocate the required number of page directories starting at the pde index of
@@ -849,13 +852,14 @@ unwind_out:
  *
  * Return: 0 if success; negative error code otherwise.
  */
-static int gen8_ppgtt_alloc_page_directories(struct i915_hw_ppgtt *ppgtt,
-				     struct i915_page_directory_pointer *pdp,
-				     uint64_t start,
-				     uint64_t length,
-				     unsigned long *new_pds)
+static int
+gen8_ppgtt_alloc_page_directories(struct i915_address_space *vm,
+				  struct i915_page_directory_pointer *pdp,
+				  uint64_t start,
+				  uint64_t length,
+				  unsigned long *new_pds)
 {
-	struct drm_device *dev = ppgtt->base.dev;
+	struct drm_device *dev = vm->dev;
 	struct i915_page_directory *pd;
 	uint64_t temp;
 	uint32_t pdpe;
@@ -871,7 +875,7 @@ static int gen8_ppgtt_alloc_page_directories(struct i915_hw_ppgtt *ppgtt,
 		if (IS_ERR(pd))
 			goto unwind_out;
 
-		gen8_initialize_pd(&ppgtt->base, pd);
+		gen8_initialize_pd(vm, pd);
 		pdp->page_directory[pdpe] = pd;
 		__set_bit(pdpe, new_pds);
 	}
@@ -947,18 +951,19 @@ static void mark_tlbs_dirty(struct i915_hw_ppgtt *ppgtt)
 }
 
 static int gen8_alloc_va_range(struct i915_address_space *vm,
-			       uint64_t start,
-			       uint64_t length)
+			       uint64_t start, uint64_t length)
 {
 	struct i915_hw_ppgtt *ppgtt =
 		container_of(vm, struct i915_hw_ppgtt, base);
 	unsigned long *new_page_dirs, **new_page_tables;
+	struct drm_device *dev = vm->dev;
+	struct i915_page_directory_pointer *pdp = &ppgtt->pdp; /* FIXME: 48b */
 	struct i915_page_directory *pd;
 	const uint64_t orig_start = start;
 	const uint64_t orig_length = length;
 	uint64_t temp;
 	uint32_t pdpe;
-	uint32_t pdpes = I915_PDPES_PER_PDP(ppgtt->base.dev);
+	uint32_t pdpes = I915_PDPES_PER_PDP(dev);
 	int ret;
 
 	/* Wrap is never okay since we can only represent 48b, and we don't
@@ -967,7 +972,7 @@ static int gen8_alloc_va_range(struct i915_address_space *vm,
 	if (WARN_ON(start + length < start))
 		return -ENODEV;
 
-	if (WARN_ON(start + length > ppgtt->base.total))
+	if (WARN_ON(start + length > vm->total))
 		return -ENODEV;
 
 	ret = alloc_gen8_temp_bitmaps(&new_page_dirs, &new_page_tables, pdpes);
@@ -975,16 +980,16 @@ static int gen8_alloc_va_range(struct i915_address_space *vm,
 		return ret;
 
 	/* Do the allocations first so we can easily bail out */
-	ret = gen8_ppgtt_alloc_page_directories(ppgtt, &ppgtt->pdp, start, length,
-					new_page_dirs);
+	ret = gen8_ppgtt_alloc_page_directories(vm, pdp, start, length,
+						new_page_dirs);
 	if (ret) {
 		free_gen8_temp_bitmaps(new_page_dirs, new_page_tables, pdpes);
 		return ret;
 	}
 
 	/* For every page directory referenced, allocate page tables */
-	gen8_for_each_pdpe(pd, &ppgtt->pdp, start, length, temp, pdpe) {
-		ret = gen8_ppgtt_alloc_pagetabs(ppgtt, pd, start, length,
+	gen8_for_each_pdpe(pd, pdp, start, length, temp, pdpe) {
+		ret = gen8_ppgtt_alloc_pagetabs(vm, pd, start, length,
 						new_page_tables[pdpe]);
 		if (ret)
 			goto err_out;
@@ -995,7 +1000,7 @@ static int gen8_alloc_va_range(struct i915_address_space *vm,
 
 	/* Allocations have completed successfully, so set the bitmaps, and do
 	 * the mappings. */
-	gen8_for_each_pdpe(pd, &ppgtt->pdp, start, length, temp, pdpe) {
+	gen8_for_each_pdpe(pd, pdp, start, length, temp, pdpe) {
 		gen8_pde_t *const page_directory = kmap_px(pd);
 		struct i915_page_table *pt;
 		uint64_t pd_len = length;
@@ -1028,8 +1033,7 @@ static int gen8_alloc_va_range(struct i915_address_space *vm,
 		}
 
 		kunmap_px(ppgtt, page_directory);
-
-		__set_bit(pdpe, ppgtt->pdp.used_pdpes);
+		__set_bit(pdpe, pdp->used_pdpes);
 	}
 
 	free_gen8_temp_bitmaps(new_page_dirs, new_page_tables, pdpes);
@@ -1039,11 +1043,11 @@ static int gen8_alloc_va_range(struct i915_address_space *vm,
 err_out:
 	while (pdpe--) {
 		for_each_set_bit(temp, new_page_tables[pdpe], I915_PDES)
-			free_pt(vm->dev, ppgtt->pdp.page_directory[pdpe]->page_table[temp]);
+			free_pt(dev, pdp->page_directory[pdpe]->page_table[temp]);
 	}
 
 	for_each_set_bit(pdpe, new_page_dirs, pdpes)
-		free_pd(vm->dev, ppgtt->pdp.page_directory[pdpe]);
+		free_pd(dev, pdp->page_directory[pdpe]);
 
 	free_gen8_temp_bitmaps(new_page_dirs, new_page_tables, pdpes);
 	mark_tlbs_dirty(ppgtt);