[PATCH v4 03/18] drm/i915/gen8: Add PML4 structure

Michel Thierry
2015-07-07T15:15:08Z

Introduces the Page Map Level 4 (PML4), ie. the new top level structure
of the page tables.

To facilitate testing, 48b mode will be available on Broadwell and
GEN9+, when i915.enable_ppgtt = 3.

Cc: Akash Goel <akash.goel@intel.com>
Signed-off-by: Michel Thierry <michel.thierry@intel.com>
---
drivers/gpu/drm/i915/i915_drv.h | 7 ++++++-
drivers/gpu/drm/i915/i915_gem_gtt.c | 40 ++++++++++++++++++++++++-------------
drivers/gpu/drm/i915/i915_gem_gtt.h | 35 ++++++++++++++++++++++++--------
3 files changed, 59 insertions(+), 23 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 464b28d..de3a5d1 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -2497,7 +2497,12 @@ struct drm_i915_cmd_table {
#define HAS_HW_CONTEXTS(dev) (INTEL_INFO(dev)->gen >= 6)
#define HAS_LOGICAL_RING_CONTEXTS(dev) (INTEL_INFO(dev)->gen >= 8)
#define USES_PPGTT(dev) (i915.enable_ppgtt)
-#define USES_FULL_PPGTT(dev) (i915.enable_ppgtt == 2)
+#define USES_FULL_PPGTT(dev) (i915.enable_ppgtt >= 2)
+#ifdef CONFIG_X86_64
+# define USES_FULL_48BIT_PPGTT(dev) (i915.enable_ppgtt == 3)
+#else
+# define USES_FULL_48BIT_PPGTT(dev) false
+#endif

#define HAS_OVERLAY(dev) (INTEL_INFO(dev)->has_overlay)
#define OVERLAY_NEEDS_PHYSICAL(dev) (INTEL_INFO(dev)->overlay_needs_physical)
diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
index 4e1501a..fa66dfa 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -104,9 +104,13 @@ static int sanitize_enable_ppgtt(struct drm_device *dev, int enable_ppgtt)
{
bool has_aliasing_ppgtt;
bool has_full_ppgtt;
+ bool has_full_64bit_ppgtt;

has_aliasing_ppgtt = INTEL_INFO(dev)->gen >= 6;
has_full_ppgtt = INTEL_INFO(dev)->gen >= 7;
+ has_full_64bit_ppgtt = IS_ENABLED(CONFIG_X86_64) &&
+ (IS_BROADWELL(dev) ||
+ INTEL_INFO(dev)->gen >= 9) && false; /* FIXME: 64b */

if (intel_vgpu_active(dev))
has_full_ppgtt = false; /* emulation is too hard */
@@ -125,6 +129,9 @@ static int sanitize_enable_ppgtt(struct drm_device *dev, int enable_ppgtt)
if (enable_ppgtt == 2 && has_full_ppgtt)
return 2;

+ if (enable_ppgtt == 3 && has_full_64bit_ppgtt)
+ return 3;
+
#ifdef CONFIG_INTEL_IOMMU
/* Disable ppgtt on SNB if VT-d is on. */
if (INTEL_INFO(dev)->gen == 6 && intel_iommu_gfx_mapped) {
@@ -557,6 +564,8 @@ static void free_pdp(struct drm_device *dev,
struct i915_page_directory_pointer *pdp)
{
__pdp_fini(pdp);
+ if (USES_FULL_48BIT_PPGTT(dev))
+ kfree(pdp);
}

/* Broadwell Page Directory Pointer Descriptors */
@@ -671,9 +680,6 @@ static void gen8_ppgtt_insert_entries(struct i915_address_space *vm,
pt_vaddr = NULL;

for_each_sg_page(pages->sgl, &sg_iter, pages->nents, 0) {
- if (WARN_ON(pdpe >= GEN8_LEGACY_PDPES))
- break;
-
if (pt_vaddr == NULL) {
struct i915_page_directory *pd = ppgtt->pdp.page_directory[pdpe];
struct i915_page_table *pt = pd->page_table[pde];
@@ -1066,14 +1072,6 @@ static int gen8_ppgtt_init(struct i915_hw_ppgtt *ppgtt)
return ret;

ppgtt->base.start = 0;
- ppgtt->base.total = 1ULL << 32;
- if (IS_ENABLED(CONFIG_X86_32))
- /* While we have a proliferation of size_t variables
- * we cannot represent the full ppgtt size on 32bit,
- * so limit it to the same size as the GGTT (currently
- * 2GiB).
- */
- ppgtt->base.total = to_i915(ppgtt->base.dev)->gtt.base.total;
ppgtt->base.cleanup = gen8_ppgtt_cleanup;
ppgtt->base.allocate_va_range = gen8_alloc_va_range;
ppgtt->base.insert_entries = gen8_ppgtt_insert_entries;
@@ -1083,10 +1081,24 @@ static int gen8_ppgtt_init(struct i915_hw_ppgtt *ppgtt)

ppgtt->switch_mm = gen8_mm_switch;

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

- if (ret)
- goto free_scratch;
+ if (ret)
+ goto free_scratch;
+
+ ppgtt->base.total = 1ULL << 32;
+ if (IS_ENABLED(CONFIG_X86_32))
+ /* While we have a proliferation of size_t variables
+ * we cannot represent the full ppgtt size on 32bit,
+ * so limit it to the same size as the GGTT (currently
+ * 2GiB).
+ */
+ ppgtt->base.total = to_i915(ppgtt->base.dev)->gtt.base.total;
+ } else {
+ ppgtt->base.total = 1ULL << 48;
+ return -EPERM; /* Not yet implemented */
+ }

return 0;

diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.h b/drivers/gpu/drm/i915/i915_gem_gtt.h
index f5928db..6fa824e 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.h
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.h
@@ -88,9 +88,17 @@ typedef uint64_t gen8_pde_t;
* PDPE | PDE | PTE | offset
* The difference as compared to normal x86 3 level page table is the PDPEs are
* programmed via register.
+ *
+ * GEN8 48b legacy style address is defined as a 4 level page table:
+ * 47:39 | 38:30 | 29:21 | 20:12 | 11:0
+ * PML4E | PDPE | PDE | PTE | offset
*/
+#define GEN8_PML4ES_PER_PML4 512
+#define GEN8_PML4E_SHIFT 39
#define GEN8_PDPE_SHIFT 30
-#define GEN8_PDPE_MASK 0x3
+/* NB: GEN8_PDPE_MASK is untrue for 32b platforms, but it has no impact on 32b page
+ * tables */
+#define GEN8_PDPE_MASK 0x1ff
#define GEN8_PDE_SHIFT 21
#define GEN8_PDE_MASK 0x1ff
#define GEN8_PTE_SHIFT 12
@@ -98,8 +106,8 @@ typedef uint64_t gen8_pde_t;
#define GEN8_LEGACY_PDPES 4
#define GEN8_PTES I915_PTES(sizeof(gen8_pte_t))

-/* FIXME: Next patch will use dev */
-#define I915_PDPES_PER_PDP(dev) GEN8_LEGACY_PDPES
+#define I915_PDPES_PER_PDP(dev) (USES_FULL_48BIT_PPGTT(dev) ?\
+ GEN8_PML4ES_PER_PML4 : GEN8_LEGACY_PDPES)

#define PPAT_UNCACHED_INDEX (_PAGE_PWT | _PAGE_PCD)
#define PPAT_CACHED_PDE_INDEX 0 /* WB LLC */
@@ -250,6 +258,13 @@ struct i915_page_directory_pointer {
struct i915_page_directory **page_directory;
};

+struct i915_pml4 {
+ struct i915_page_dma base;
+
+ DECLARE_BITMAP(used_pml4es, GEN8_PML4ES_PER_PML4);
+ struct i915_page_directory_pointer *pdps[GEN8_PML4ES_PER_PML4];
+};
+
struct i915_address_space {
struct drm_mm mm;
struct drm_device *dev;
@@ -345,8 +360,9 @@ struct i915_hw_ppgtt {
struct drm_mm_node node;
unsigned long pd_dirty_rings;
union {
- struct i915_page_directory_pointer pdp;
- struct i915_page_directory pd;
+ struct i915_pml4 pml4; /* GEN8+ & 48b PPGTT */
+ struct i915_page_directory_pointer pdp; /* GEN8+ */
+ struct i915_page_directory pd; /* GEN6-7 */
};

struct drm_i915_file_private *file_priv;
@@ -440,14 +456,17 @@ static inline uint32_t gen6_pde_index(uint32_t addr)
temp = min(temp, length), \
start += temp, length -= temp)

-#define gen8_for_each_pdpe(pd, pdp, start, length, temp, iter) \
- for (iter = gen8_pdpe_index(start); \
- pd = (pdp)->page_directory[iter], length > 0 && iter < GEN8_LEGACY_PDPES; \
+#define gen8_for_each_pdpe_e(pd, pdp, start, length, temp, iter, b) \
+ for (iter = gen8_pdpe_index(start); \
+ pd = (pdp)->page_directory[iter], length > 0 && (iter < b); \
iter++, \
temp = ALIGN(start+1, 1 << GEN8_PDPE_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))
+
static inline uint32_t gen8_pte_index(uint64_t address)
{
return i915_pte_index(address, GEN8_PDE_SHIFT);
--
2.4.5