Re: [PATCH v6 06/19] drm/i915/gen8: Add PML4 structure

["Goel, Akash" <akash.goel@intel.com>]

On 7/29/2015 9:53 PM, Michel Thierry wrote:
> 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.
>
> v2: Remove unnecessary CONFIG_X86_64 checks, ppgtt code is already
> 32/64-bit safe (Chris).
> v3: Add goto free_scratch in temp 48-bit mode init code (Akash).
>
> Cc: Akash Goel <akash.goel@intel.com>
> Signed-off-by: Michel Thierry <michel.thierry@intel.com>
> ---
>   drivers/gpu/drm/i915/i915_drv.h     |  3 ++-
>   drivers/gpu/drm/i915/i915_gem_gtt.c | 38 ++++++++++++++++++++++++-------------
>   drivers/gpu/drm/i915/i915_gem_gtt.h | 26 ++++++++++++++++++++-----
>   3 files changed, 48 insertions(+), 19 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 40fea41..0b5cbe8 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -2498,7 +2498,8 @@ 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)
> +#define USES_FULL_48BIT_PPGTT(dev)	(i915.enable_ppgtt == 3)
>
>   #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 8c1db92..1a120a4 100644
> --- a/drivers/gpu/drm/i915/i915_gem_gtt.c
> +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
> @@ -104,9 +104,12 @@ 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_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 +128,9 @@ 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 +563,8 @@ 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);

Sorry for the late comment.
This change is a bit of distraction here, should be moved to the 
following 'alloc/free for 4lvl' patch.

Best regards
Akash

>   }
>
>   /* Broadwell Page Directory Pointer Descriptors */
> @@ -686,9 +694,6 @@ gen8_ppgtt_insert_pte_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 = pdp->page_directory[pdpe];
>   			struct i915_page_table *pt = pd->page_table[pde];
> @@ -1102,14 +1107,6 @@ 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;
> @@ -1119,10 +1116,25 @@ 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)
> +		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;
> +		ret = -EPERM; /* Not yet implemented */
>   		goto free_scratch;
> +	}
>
>   	return 0;
>
> diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.h b/drivers/gpu/drm/i915/i915_gem_gtt.h
> index 87e389c..04bc66f 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;
>
_______________________________________________
Intel-gfx mailing list
Intel-gfx@lists.freedesktop.org
http://lists.freedesktop.org/mailman/listinfo/intel-gfx