[Intel-gfx] [PATCH v5 07/19] drm/i915/migrate: add acceleration support for DG2

Matthew Auld matthew.auld at intel.com
Tue Feb 1 10:49:58 UTC 2022


On 01/02/2022 10:41, Ramalingam C wrote:
> From: Matthew Auld <matthew.auld at intel.com>
> 
> This is all kinds of awkward since we now have to contend with using 64K
> GTT pages when mapping anything in LMEM(including the page-tables
> themselves).
> 
> v2: Rebased [Ram]
> 
> Signed-off-by: Matthew Auld <matthew.auld at intel.com>
> Cc: Thomas Hellström <thomas.hellstrom at linux.intel.com>
> Cc: Ramalingam C <ramalingam.c at intel.com>

This version seems to be missing your review feedback, which I 
incorporated here[1].

[1] https://patchwork.freedesktop.org/series/97544/

> ---
>   drivers/gpu/drm/i915/gt/intel_migrate.c | 179 +++++++++++++++++++-----
>   1 file changed, 147 insertions(+), 32 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/gt/intel_migrate.c b/drivers/gpu/drm/i915/gt/intel_migrate.c
> index 18b44af56969..cac791155244 100644
> --- a/drivers/gpu/drm/i915/gt/intel_migrate.c
> +++ b/drivers/gpu/drm/i915/gt/intel_migrate.c
> @@ -32,6 +32,38 @@ static bool engine_supports_migration(struct intel_engine_cs *engine)
>   	return true;
>   }
>   
> +static void xehpsdv_toggle_pdes(struct i915_address_space *vm,
> +				struct i915_page_table *pt,
> +				void *data)
> +{
> +	struct insert_pte_data *d = data;
> +
> +	/*
> +	 * Insert a dummy PTE into every PT that will map to LMEM to ensure
> +	 * we have a correctly setup PDE structure for later use.
> +	 */
> +	vm->insert_page(vm, 0, d->offset, I915_CACHE_NONE, PTE_LM);
> +	GEM_BUG_ON(!pt->is_compact);
> +	d->offset += SZ_2M;
> +}
> +
> +static void xehpsdv_insert_pte(struct i915_address_space *vm,
> +			       struct i915_page_table *pt,
> +			       void *data)
> +{
> +	struct insert_pte_data *d = data;
> +
> +	/*
> +	 * We are playing tricks here, since the actual pt, from the hw
> +	 * pov, is only 256bytes with 32 entries, or 4096bytes with 512
> +	 * entries, but we are still guaranteed that the physical
> +	 * alignment is 64K underneath for the pt, and we are careful
> +	 * not to access the space in the void.
> +	 */
> +	vm->insert_page(vm, px_dma(pt), d->offset, I915_CACHE_NONE, PTE_LM);
> +	d->offset += SZ_64K;
> +}
> +
>   static void insert_pte(struct i915_address_space *vm,
>   		       struct i915_page_table *pt,
>   		       void *data)
> @@ -74,7 +106,12 @@ static struct i915_address_space *migrate_vm(struct intel_gt *gt)
>   	 * i.e. within the same non-preemptible window so that we do not switch
>   	 * to another migration context that overwrites the PTE.
>   	 *
> -	 * TODO: Add support for huge LMEM PTEs
> +	 * On platforms with HAS_64K_PAGES support we have three windows, and
> +	 * dedicate two windows just for mapping lmem pages(smem <-> smem is not
> +	 * a thing), since we are forced to use 64K GTT pages underneath which
> +	 * requires also modifying the PDE. An alternative might be to instead
> +	 * map the PD into the GTT, and then on the fly toggle the 4K/64K mode
> +	 * in the PDE from the same batch that also modifies the PTEs.
>   	 */
>   
>   	vm = i915_ppgtt_create(gt, I915_BO_ALLOC_PM_EARLY);
> @@ -86,6 +123,9 @@ static struct i915_address_space *migrate_vm(struct intel_gt *gt)
>   		goto err_vm;
>   	}
>   
> +	if (HAS_64K_PAGES(gt->i915))
> +		stash.pt_sz = I915_GTT_PAGE_SIZE_64K;
> +
>   	/*
>   	 * Each engine instance is assigned its own chunk in the VM, so
>   	 * that we can run multiple instances concurrently
> @@ -105,14 +145,20 @@ static struct i915_address_space *migrate_vm(struct intel_gt *gt)
>   		 * We copy in 8MiB chunks. Each PDE covers 2MiB, so we need
>   		 * 4x2 page directories for source/destination.
>   		 */
> -		sz = 2 * CHUNK_SZ;
> +		if (HAS_64K_PAGES(gt->i915))
> +			sz = 3 * CHUNK_SZ;
> +		else
> +			sz = 2 * CHUNK_SZ;
>   		d.offset = base + sz;
>   
>   		/*
>   		 * We need another page directory setup so that we can write
>   		 * the 8x512 PTE in each chunk.
>   		 */
> -		sz += (sz >> 12) * sizeof(u64);
> +		if (HAS_64K_PAGES(gt->i915))
> +			sz += (sz / SZ_2M) * SZ_64K;
> +		else
> +			sz += (sz >> 12) * sizeof(u64);
>   
>   		err = i915_vm_alloc_pt_stash(&vm->vm, &stash, sz);
>   		if (err)
> @@ -133,7 +179,18 @@ static struct i915_address_space *migrate_vm(struct intel_gt *gt)
>   			goto err_vm;
>   
>   		/* Now allow the GPU to rewrite the PTE via its own ppGTT */
> -		vm->vm.foreach(&vm->vm, base, d.offset - base, insert_pte, &d);
> +		if (HAS_64K_PAGES(gt->i915)) {
> +			vm->vm.foreach(&vm->vm, base, d.offset - base,
> +				       xehpsdv_insert_pte, &d);
> +			d.offset = base + CHUNK_SZ;
> +			vm->vm.foreach(&vm->vm,
> +				       d.offset,
> +				       2 * CHUNK_SZ,
> +				       xehpsdv_toggle_pdes, &d);
> +		} else {
> +			vm->vm.foreach(&vm->vm, base, d.offset - base,
> +				       insert_pte, &d);
> +		}
>   	}
>   
>   	return &vm->vm;
> @@ -269,19 +326,38 @@ static int emit_pte(struct i915_request *rq,
>   		    u64 offset,
>   		    int length)
>   {
> +	bool has_64K_pages = HAS_64K_PAGES(rq->engine->i915);
>   	const u64 encode = rq->context->vm->pte_encode(0, cache_level,
>   						       is_lmem ? PTE_LM : 0);
>   	struct intel_ring *ring = rq->ring;
> -	int total = 0;
> +	int pkt, dword_length;
> +	u32 total = 0;
> +	u32 page_size;
>   	u32 *hdr, *cs;
> -	int pkt;
>   
>   	GEM_BUG_ON(GRAPHICS_VER(rq->engine->i915) < 8);
>   
> +	page_size = I915_GTT_PAGE_SIZE;
> +	dword_length = 0x400;
> +
>   	/* Compute the page directory offset for the target address range */
> -	offset >>= 12;
> -	offset *= sizeof(u64);
> -	offset += 2 * CHUNK_SZ;
> +	if (has_64K_pages) {
> +		GEM_BUG_ON(!IS_ALIGNED(offset, SZ_2M));
> +
> +		offset /= SZ_2M;
> +		offset *= SZ_64K;
> +		offset += 3 * CHUNK_SZ;
> +
> +		if (is_lmem) {
> +			page_size = I915_GTT_PAGE_SIZE_64K;
> +			dword_length = 0x40;
> +		}
> +	} else {
> +		offset >>= 12;
> +		offset *= sizeof(u64);
> +		offset += 2 * CHUNK_SZ;
> +	}
> +
>   	offset += (u64)rq->engine->instance << 32;
>   
>   	cs = intel_ring_begin(rq, 6);
> @@ -289,7 +365,7 @@ static int emit_pte(struct i915_request *rq,
>   		return PTR_ERR(cs);
>   
>   	/* Pack as many PTE updates as possible into a single MI command */
> -	pkt = min_t(int, 0x400, ring->space / sizeof(u32) + 5);
> +	pkt = min_t(int, dword_length, ring->space / sizeof(u32) + 5);
>   	pkt = min_t(int, pkt, (ring->size - ring->emit) / sizeof(u32) + 5);
>   
>   	hdr = cs;
> @@ -299,6 +375,8 @@ static int emit_pte(struct i915_request *rq,
>   
>   	do {
>   		if (cs - hdr >= pkt) {
> +			int dword_rem;
> +
>   			*hdr += cs - hdr - 2;
>   			*cs++ = MI_NOOP;
>   
> @@ -310,7 +388,18 @@ static int emit_pte(struct i915_request *rq,
>   			if (IS_ERR(cs))
>   				return PTR_ERR(cs);
>   
> -			pkt = min_t(int, 0x400, ring->space / sizeof(u32) + 5);
> +			dword_rem = dword_length;
> +			if (has_64K_pages) {
> +				if (IS_ALIGNED(total, SZ_2M)) {
> +					offset = round_up(offset, SZ_64K);
> +				} else {
> +					dword_rem = SZ_2M - (total & (SZ_2M - 1));
> +					dword_rem /= page_size;
> +					dword_rem *= 2;
> +				}
> +			}
> +
> +			pkt = min_t(int, dword_rem, ring->space / sizeof(u32) + 5);
>   			pkt = min_t(int, pkt, (ring->size - ring->emit) / sizeof(u32) + 5);
>   
>   			hdr = cs;
> @@ -319,13 +408,15 @@ static int emit_pte(struct i915_request *rq,
>   			*cs++ = upper_32_bits(offset);
>   		}
>   
> +		GEM_BUG_ON(!IS_ALIGNED(it->dma, page_size));
> +
>   		*cs++ = lower_32_bits(encode | it->dma);
>   		*cs++ = upper_32_bits(encode | it->dma);
>   
>   		offset += 8;
> -		total += I915_GTT_PAGE_SIZE;
> +		total += page_size;
>   
> -		it->dma += I915_GTT_PAGE_SIZE;
> +		it->dma += page_size;
>   		if (it->dma >= it->max) {
>   			it->sg = __sg_next(it->sg);
>   			if (!it->sg || sg_dma_len(it->sg) == 0)
> @@ -356,7 +447,8 @@ static bool wa_1209644611_applies(int ver, u32 size)
>   	return height % 4 == 3 && height <= 8;
>   }
>   
> -static int emit_copy(struct i915_request *rq, int size)
> +static int emit_copy(struct i915_request *rq,
> +		     u32 dst_offset, u32 src_offset, int size)
>   {
>   	const int ver = GRAPHICS_VER(rq->engine->i915);
>   	u32 instance = rq->engine->instance;
> @@ -371,31 +463,31 @@ static int emit_copy(struct i915_request *rq, int size)
>   		*cs++ = BLT_DEPTH_32 | PAGE_SIZE;
>   		*cs++ = 0;
>   		*cs++ = size >> PAGE_SHIFT << 16 | PAGE_SIZE / 4;
> -		*cs++ = CHUNK_SZ; /* dst offset */
> +		*cs++ = dst_offset;
>   		*cs++ = instance;
>   		*cs++ = 0;
>   		*cs++ = PAGE_SIZE;
> -		*cs++ = 0; /* src offset */
> +		*cs++ = src_offset;
>   		*cs++ = instance;
>   	} else if (ver >= 8) {
>   		*cs++ = XY_SRC_COPY_BLT_CMD | BLT_WRITE_RGBA | (10 - 2);
>   		*cs++ = BLT_DEPTH_32 | BLT_ROP_SRC_COPY | PAGE_SIZE;
>   		*cs++ = 0;
>   		*cs++ = size >> PAGE_SHIFT << 16 | PAGE_SIZE / 4;
> -		*cs++ = CHUNK_SZ; /* dst offset */
> +		*cs++ = dst_offset;
>   		*cs++ = instance;
>   		*cs++ = 0;
>   		*cs++ = PAGE_SIZE;
> -		*cs++ = 0; /* src offset */
> +		*cs++ = src_offset;
>   		*cs++ = instance;
>   	} else {
>   		GEM_BUG_ON(instance);
>   		*cs++ = SRC_COPY_BLT_CMD | BLT_WRITE_RGBA | (6 - 2);
>   		*cs++ = BLT_DEPTH_32 | BLT_ROP_SRC_COPY | PAGE_SIZE;
>   		*cs++ = size >> PAGE_SHIFT << 16 | PAGE_SIZE;
> -		*cs++ = CHUNK_SZ; /* dst offset */
> +		*cs++ = dst_offset;
>   		*cs++ = PAGE_SIZE;
> -		*cs++ = 0; /* src offset */
> +		*cs++ = src_offset;
>   	}
>   
>   	intel_ring_advance(rq, cs);
> @@ -423,6 +515,7 @@ intel_context_migrate_copy(struct intel_context *ce,
>   	GEM_BUG_ON(ce->ring->size < SZ_64K);
>   
>   	do {
> +		u32 src_offset, dst_offset;
>   		int len;
>   
>   		rq = i915_request_create(ce);
> @@ -450,15 +543,28 @@ intel_context_migrate_copy(struct intel_context *ce,
>   		if (err)
>   			goto out_rq;
>   
> -		len = emit_pte(rq, &it_src, src_cache_level, src_is_lmem, 0,
> -			       CHUNK_SZ);
> +		src_offset = 0;
> +		dst_offset = CHUNK_SZ;
> +		if (HAS_64K_PAGES(ce->engine->i915)) {
> +			GEM_BUG_ON(!src_is_lmem && !dst_is_lmem);
> +
> +			src_offset = 0;
> +			dst_offset = 0;
> +			if (src_is_lmem)
> +				src_offset = CHUNK_SZ;
> +			if (dst_is_lmem)
> +				dst_offset = 2 * CHUNK_SZ;
> +		}
> +
> +		len = emit_pte(rq, &it_src, src_cache_level, src_is_lmem,
> +			       src_offset, CHUNK_SZ);
>   		if (len <= 0) {
>   			err = len;
>   			goto out_rq;
>   		}
>   
>   		err = emit_pte(rq, &it_dst, dst_cache_level, dst_is_lmem,
> -			       CHUNK_SZ, len);
> +			       dst_offset, len);
>   		if (err < 0)
>   			goto out_rq;
>   		if (err < len) {
> @@ -470,7 +576,7 @@ intel_context_migrate_copy(struct intel_context *ce,
>   		if (err)
>   			goto out_rq;
>   
> -		err = emit_copy(rq, len);
> +		err = emit_copy(rq, dst_offset, src_offset, len);
>   
>   		/* Arbitration is re-enabled between requests. */
>   out_rq:
> @@ -488,14 +594,18 @@ intel_context_migrate_copy(struct intel_context *ce,
>   	return err;
>   }
>   
> -static int emit_clear(struct i915_request *rq, int size, u32 value)
> +static int emit_clear(struct i915_request *rq,
> +		      u64 offset,
> +		      int size,
> +		      u32 value)
>   {
>   	const int ver = GRAPHICS_VER(rq->engine->i915);
> -	u32 instance = rq->engine->instance;
>   	u32 *cs;
>   
>   	GEM_BUG_ON(size >> PAGE_SHIFT > S16_MAX);
>   
> +	offset += (u64)rq->engine->instance << 32;
> +
>   	cs = intel_ring_begin(rq, ver >= 8 ? 8 : 6);
>   	if (IS_ERR(cs))
>   		return PTR_ERR(cs);
> @@ -505,17 +615,17 @@ static int emit_clear(struct i915_request *rq, int size, u32 value)
>   		*cs++ = BLT_DEPTH_32 | BLT_ROP_COLOR_COPY | PAGE_SIZE;
>   		*cs++ = 0;
>   		*cs++ = size >> PAGE_SHIFT << 16 | PAGE_SIZE / 4;
> -		*cs++ = 0; /* offset */
> -		*cs++ = instance;
> +		*cs++ = lower_32_bits(offset);
> +		*cs++ = upper_32_bits(offset);
>   		*cs++ = value;
>   		*cs++ = MI_NOOP;
>   	} else {
> -		GEM_BUG_ON(instance);
> +		GEM_BUG_ON(upper_32_bits(offset));
>   		*cs++ = XY_COLOR_BLT_CMD | BLT_WRITE_RGBA | (6 - 2);
>   		*cs++ = BLT_DEPTH_32 | BLT_ROP_COLOR_COPY | PAGE_SIZE;
>   		*cs++ = 0;
>   		*cs++ = size >> PAGE_SHIFT << 16 | PAGE_SIZE / 4;
> -		*cs++ = 0;
> +		*cs++ = lower_32_bits(offset);
>   		*cs++ = value;
>   	}
>   
> @@ -542,6 +652,7 @@ intel_context_migrate_clear(struct intel_context *ce,
>   	GEM_BUG_ON(ce->ring->size < SZ_64K);
>   
>   	do {
> +		u32 offset;
>   		int len;
>   
>   		rq = i915_request_create(ce);
> @@ -569,7 +680,11 @@ intel_context_migrate_clear(struct intel_context *ce,
>   		if (err)
>   			goto out_rq;
>   
> -		len = emit_pte(rq, &it, cache_level, is_lmem, 0, CHUNK_SZ);
> +		offset = 0;
> +		if (HAS_64K_PAGES(ce->engine->i915) && is_lmem)
> +			offset = CHUNK_SZ;
> +
> +		len = emit_pte(rq, &it, cache_level, is_lmem, offset, CHUNK_SZ);
>   		if (len <= 0) {
>   			err = len;
>   			goto out_rq;
> @@ -579,7 +694,7 @@ intel_context_migrate_clear(struct intel_context *ce,
>   		if (err)
>   			goto out_rq;
>   
> -		err = emit_clear(rq, len, value);
> +		err = emit_clear(rq, offset, len, value);
>   
>   		/* Arbitration is re-enabled between requests. */
>   out_rq:


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