[PATCH v4 06/18] drm/i915/gen8: implement alloc/free for 4lvl

Michel Thierry
2015-07-07T15:15:11Z

PML4 has no special attributes, and there will always be a PML4.
So simply initialize it at creation, and destroy it at the end.

The code for 4lvl is able to call into the existing 3lvl page table code
to handle all of the lower levels.

v2: Return something at the end of gen8_alloc_va_range_4lvl to keep the
compiler happy. And define ret only in one place.
Updated gen8_ppgtt_unmap_pages and gen8_ppgtt_free to handle 4lvl.
v3: Use i915_dma_unmap_single instead of pci API. Fix a
couple of incorrect checks when unmapping pdp and pd pages (Akash).
v4: Call __pdp_fini also for 32b PPGTT. Clean up alloc_pdp param list.
v5: Prevent (harmless) out of range access in gen8_for_each_pml4e.
v6: Simplify alloc_vma_range_4lvl and gen8_ppgtt_init_common error
paths. (Akash)
v7: Rebase, s/gen8_ppgtt_free_*/gen8_ppgtt_cleanup_*/.
v8: Change location of pml4_init/fini. It will make next patches
cleaner.
v9: Rebase after Mika's ppgtt cleanup / scratch merge patch series, while
trying to reuse as much as possible for pdp alloc. pml4_init/fini
replaced by setup/cleanup_px macros.
v10: Rebase after Mika's merged ppgtt cleanup patch series.
v11: Rebase after final merged version of Mika's ppgtt/scratch
patches.
v12: Fix pdpe start value in trace (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+)
---
drivers/gpu/drm/i915/i915_gem_gtt.c | 161 ++++++++++++++++++++++++++++++------
drivers/gpu/drm/i915/i915_gem_gtt.h | 12 ++-
2 files changed, 145 insertions(+), 28 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
index 425ce65..33df9b7 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -560,12 +560,44 @@ static void __pdp_fini(struct i915_page_directory_pointer *pdp)
pdp->page_directory = NULL;
}

+static struct
+i915_page_directory_pointer *alloc_pdp(struct drm_device *dev)
+{
+ struct i915_page_directory_pointer *pdp;
+ int ret = -ENOMEM;
+
+ WARN_ON(!USES_FULL_48BIT_PPGTT(dev));
+
+ pdp = kzalloc(sizeof(*pdp), GFP_KERNEL);
+ if (!pdp)
+ return ERR_PTR(-ENOMEM);
+
+ ret = __pdp_init(dev, pdp);
+ if (ret)
+ goto fail_bitmap;
+
+ ret = setup_px(dev, pdp);
+ if (ret)
+ goto fail_page_m;
+
+ return pdp;
+
+fail_page_m:
+ __pdp_fini(pdp);
+fail_bitmap:
+ kfree(pdp);
+
+ return ERR_PTR(ret);
+}
+
static void free_pdp(struct drm_device *dev,
struct i915_page_directory_pointer *pdp)
{
__pdp_fini(pdp);
- if (USES_FULL_48BIT_PPGTT(dev))
+ if (USES_FULL_48BIT_PPGTT(dev)) {
+ cleanup_px(dev, pdp);
kfree(pdp);
+ }
}

/* Broadwell Page Directory Pointer Descriptors */
@@ -759,28 +791,46 @@ static void gen8_free_scratch(struct i915_address_space *vm)
free_scratch_page(dev, vm->scratch_page);
}

-static void gen8_ppgtt_cleanup(struct i915_address_space *vm)
+static void gen8_ppgtt_cleanup_3lvl(struct drm_device *dev,
+ struct i915_page_directory_pointer *pdp)
{
- struct i915_hw_ppgtt *ppgtt =
- container_of(vm, struct i915_hw_ppgtt, base);
int i;

- if (!USES_FULL_48BIT_PPGTT(ppgtt->base.dev)) {
- for_each_set_bit(i, ppgtt->pdp.used_pdpes,
- I915_PDPES_PER_PDP(ppgtt->base.dev)) {
- if (WARN_ON(!ppgtt->pdp.page_directory[i]))
- continue;
+ 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]);
- }
- free_pdp(ppgtt->base.dev, &ppgtt->pdp);
- } else {
- WARN_ON(1); /* to be implemented later */
+ gen8_free_page_tables(dev, pdp->page_directory[i]);
+ free_pd(dev, pdp->page_directory[i]);
+ }
+
+ free_pdp(dev, pdp);
+}
+
+static void gen8_ppgtt_cleanup_4lvl(struct i915_hw_ppgtt *ppgtt)
+{
+ int i;
+
+ for_each_set_bit(i, ppgtt->pml4.used_pml4es, GEN8_PML4ES_PER_PML4) {
+ if (WARN_ON(!ppgtt->pml4.pdps[i]))
+ continue;
+
+ gen8_ppgtt_cleanup_3lvl(ppgtt->base.dev, ppgtt->pml4.pdps[i]);
}

+ cleanup_px(ppgtt->base.dev, &ppgtt->pml4);
+}
+
+static void gen8_ppgtt_cleanup(struct i915_address_space *vm)
+{
+ struct i915_hw_ppgtt *ppgtt =
+ container_of(vm, struct i915_hw_ppgtt, base);
+
+ if (!USES_FULL_48BIT_PPGTT(ppgtt->base.dev))
+ gen8_ppgtt_cleanup_3lvl(ppgtt->base.dev, &ppgtt->pdp);
+ else
+ gen8_ppgtt_cleanup_4lvl(ppgtt);
+
gen8_free_scratch(vm);
}

@@ -1075,8 +1125,61 @@ static int gen8_alloc_va_range_4lvl(struct i915_address_space *vm,
uint64_t start,
uint64_t length)
{
- WARN_ON(1); /* to be implemented later */
+ DECLARE_BITMAP(new_pdps, GEN8_PML4ES_PER_PML4);
+ struct i915_page_directory_pointer *pdp;
+ const uint64_t orig_start = start;
+ const uint64_t orig_length = length;
+ uint64_t temp, pml4e;
+ int ret = 0;
+
+ /* Do the pml4 allocations first, so we don't need to track the newly
+ * allocated tables below the pdp */
+ bitmap_zero(new_pdps, GEN8_PML4ES_PER_PML4);
+
+ /* The pagedirectory and pagetable allocations are done in the shared 3
+ * and 4 level code. Just allocate the pdps.
+ */
+ gen8_for_each_pml4e(pdp, pml4, start, length, temp, pml4e) {
+ if (!pdp) {
+ WARN_ON(test_bit(pml4e, pml4->used_pml4es));
+ pdp = alloc_pdp(vm->dev);
+ if (IS_ERR(pdp))
+ goto err_out;
+
+ pml4->pdps[pml4e] = pdp;
+ __set_bit(pml4e, new_pdps);
+ trace_i915_page_directory_pointer_entry_alloc(vm,
+ pml4e,
+ start,
+ GEN8_PML4E_SHIFT);
+ }
+ }
+
+ WARN(bitmap_weight(new_pdps, GEN8_PML4ES_PER_PML4) > 2,
+ "The allocation has spanned more than 512GB. "
+ "It is highly likely this is incorrect.");
+
+ start = orig_start;
+ length = orig_length;
+
+ gen8_for_each_pml4e(pdp, pml4, start, length, temp, pml4e) {
+ WARN_ON(!pdp);
+
+ ret = gen8_alloc_va_range_3lvl(vm, pdp, start, length);
+ if (ret)
+ goto err_out;
+ }
+
+ bitmap_or(pml4->used_pml4es, new_pdps, pml4->used_pml4es,
+ GEN8_PML4ES_PER_PML4);
+
return 0;
+
+err_out:
+ for_each_set_bit(pml4e, new_pdps, GEN8_PML4ES_PER_PML4)
+ gen8_ppgtt_cleanup_3lvl(vm->dev, pml4->pdps[pml4e]);
+
+ return ret;
}

static int gen8_alloc_va_range(struct i915_address_space *vm,
@@ -1085,10 +1188,10 @@ static int gen8_alloc_va_range(struct i915_address_space *vm,
struct i915_hw_ppgtt *ppgtt =
container_of(vm, struct i915_hw_ppgtt, base);

- if (!USES_FULL_48BIT_PPGTT(vm->dev))
- return gen8_alloc_va_range_3lvl(vm, &ppgtt->pdp, start, length);
- else
+ if (USES_FULL_48BIT_PPGTT(vm->dev))
return gen8_alloc_va_range_4lvl(vm, &ppgtt->pml4, start, length);
+ else
+ return gen8_alloc_va_range_3lvl(vm, &ppgtt->pdp, start, length);
}

/*
@@ -1116,9 +1219,14 @@ static int gen8_ppgtt_init(struct i915_hw_ppgtt *ppgtt)

ppgtt->switch_mm = gen8_mm_switch;

- if (!USES_FULL_48BIT_PPGTT(ppgtt->base.dev)) {
- ret = __pdp_init(false, &ppgtt->pdp);
+ if (USES_FULL_48BIT_PPGTT(ppgtt->base.dev)) {
+ ret = setup_px(ppgtt->base.dev, &ppgtt->pml4);
+ if (ret)
+ goto free_scratch;

+ ppgtt->base.total = 1ULL << 48;
+ } else {
+ ret = __pdp_init(false, &ppgtt->pdp);
if (ret)
goto free_scratch;

@@ -1130,9 +1238,10 @@ static int gen8_ppgtt_init(struct i915_hw_ppgtt *ppgtt)
* 2GiB).
*/
ppgtt->base.total = to_i915(ppgtt->base.dev)->gtt.base.total;
- } else {
- ppgtt->base.total = 1ULL << 48;
- return -EPERM; /* Not yet implemented */
+
+ trace_i915_page_directory_pointer_entry_alloc(&ppgtt->base,
+ 0, 0,
+ GEN8_PML4E_SHIFT);
}

return 0;
diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.h b/drivers/gpu/drm/i915/i915_gem_gtt.h
index 6fa824e..660c9a5 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.h
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.h
@@ -95,6 +95,7 @@ typedef uint64_t gen8_pde_t;
*/
#define GEN8_PML4ES_PER_PML4 512
#define GEN8_PML4E_SHIFT 39
+#define GEN8_PML4E_MASK (GEN8_PML4ES_PER_PML4 - 1)
#define GEN8_PDPE_SHIFT 30
/* NB: GEN8_PDPE_MASK is untrue for 32b platforms, but it has no impact on 32b page
* tables */
@@ -464,6 +465,14 @@ static inline uint32_t gen6_pde_index(uint32_t addr)
temp = min(temp, length), \
start += temp, length -= temp)

+#define gen8_for_each_pml4e(pdp, pml4, start, length, temp, iter) \
+ for (iter = gen8_pml4e_index(start); \
+ pdp = (pml4)->pdps[iter], length > 0 && iter < GEN8_PML4ES_PER_PML4; \
+ iter++, \
+ temp = ALIGN(start+1, 1ULL << GEN8_PML4E_SHIFT) - start, \
+ temp = min(temp, length), \
+ start += temp, length -= temp)
+
#define gen8_for_each_pdpe(pd, pdp, start, length, temp, iter) \
gen8_for_each_pdpe_e(pd, pdp, start, length, temp, iter, I915_PDPES_PER_PDP(dev))

@@ -484,8 +493,7 @@ static inline uint32_t gen8_pdpe_index(uint64_t address)

static inline uint32_t gen8_pml4e_index(uint64_t address)
{
- WARN_ON(1); /* For 64B */
- return 0;
+ return (address >> GEN8_PML4E_SHIFT) & GEN8_PML4E_MASK;
}

static inline size_t gen8_pte_count(uint64_t address, uint64_t length)
--
2.4.5