1 files changed, 688 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/gt/intel_migrate.c b/drivers/gpu/drm/i915/gt/intel_migrate.c
new file mode 100644
index 000000000000..1dac21aa7e5c
--- /dev/null
+++ b/drivers/gpu/drm/i915/gt/intel_migrate.c
@@ -0,0 +1,688 @@
+// SPDX-License-Identifier: MIT
+/*
+ * Copyright © 2020 Intel Corporation
+ */
+
+#include "i915_drv.h"
+#include "intel_context.h"
+#include "intel_gpu_commands.h"
+#include "intel_gt.h"
+#include "intel_gtt.h"
+#include "intel_migrate.h"
+#include "intel_ring.h"
+
+struct insert_pte_data {
+	u64 offset;
+	bool is_lmem;
+};
+
+#define CHUNK_SZ SZ_8M /* ~1ms at 8GiB/s preemption delay */
+
+static bool engine_supports_migration(struct intel_engine_cs *engine)
+{
+	if (!engine)
+		return false;
+
+	/*
+	 * We need the ability to prevent aribtration (MI_ARB_ON_OFF),
+	 * the ability to write PTE using inline data (MI_STORE_DATA)
+	 * and of course the ability to do the block transfer (blits).
+	 */
+	GEM_BUG_ON(engine->class != COPY_ENGINE_CLASS);
+
+	return true;
+}
+
+static void insert_pte(struct i915_address_space *vm,
+		       struct i915_page_table *pt,
+		       void *data)
+{
+	struct insert_pte_data *d = data;
+
+	vm->insert_page(vm, px_dma(pt), d->offset, I915_CACHE_NONE,
+			d->is_lmem ? PTE_LM : 0);
+	d->offset += PAGE_SIZE;
+}
+
+static struct i915_address_space *migrate_vm(struct intel_gt *gt)
+{
+	struct i915_vm_pt_stash stash = {};
+	struct i915_ppgtt *vm;
+	int err;
+	int i;
+
+	/*
+	 * We construct a very special VM for use by all migration contexts,
+	 * it is kept pinned so that it can be used at any time. As we need
+	 * to pre-allocate the page directories for the migration VM, this
+	 * limits us to only using a small number of prepared vma.
+	 *
+	 * To be able to pipeline and reschedule migration operations while
+	 * avoiding unnecessary contention on the vm itself, the PTE updates
+	 * are inline with the blits. All the blits use the same fixed
+	 * addresses, with the backing store redirection being updated on the
+	 * fly. Only 2 implicit vma are used for all migration operations.
+	 *
+	 * We lay the ppGTT out as:
+	 *
+	 *	[0, CHUNK_SZ) -> first object
+	 *	[CHUNK_SZ, 2 * CHUNK_SZ) -> second object
+	 *	[2 * CHUNK_SZ, 2 * CHUNK_SZ + 2 * CHUNK_SZ >> 9] -> PTE
+	 *
+	 * By exposing the dma addresses of the page directories themselves
+	 * within the ppGTT, we are then able to rewrite the PTE prior to use.
+	 * But the PTE update and subsequent migration operation must be atomic,
+	 * 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
+	 */
+
+	vm = i915_ppgtt_create(gt);
+	if (IS_ERR(vm))
+		return ERR_CAST(vm);
+
+	if (!vm->vm.allocate_va_range || !vm->vm.foreach) {
+		err = -ENODEV;
+		goto err_vm;
+	}
+
+	/*
+	 * Each engine instance is assigned its own chunk in the VM, so
+	 * that we can run multiple instances concurrently
+	 */
+	for (i = 0; i < ARRAY_SIZE(gt->engine_class[COPY_ENGINE_CLASS]); i++) {
+		struct intel_engine_cs *engine;
+		u64 base = (u64)i << 32;
+		struct insert_pte_data d = {};
+		struct i915_gem_ww_ctx ww;
+		u64 sz;
+
+		engine = gt->engine_class[COPY_ENGINE_CLASS][i];
+		if (!engine_supports_migration(engine))
+			continue;
+
+		/*
+		 * We copy in 8MiB chunks. Each PDE covers 2MiB, so we need
+		 * 4x2 page directories for source/destination.
+		 */
+		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);
+
+		err = i915_vm_alloc_pt_stash(&vm->vm, &stash, sz);
+		if (err)
+			goto err_vm;
+
+		for_i915_gem_ww(&ww, err, true) {
+			err = i915_vm_lock_objects(&vm->vm, &ww);
+			if (err)
+				continue;
+			err = i915_vm_map_pt_stash(&vm->vm, &stash);
+			if (err)
+				continue;
+
+			vm->vm.allocate_va_range(&vm->vm, &stash, base, sz);
+		}
+		i915_vm_free_pt_stash(&vm->vm, &stash);
+		if (err)
+			goto err_vm;
+
+		/* Now allow the GPU to rewrite the PTE via its own ppGTT */
+		d.is_lmem = i915_gem_object_is_lmem(vm->vm.scratch[0]);
+		vm->vm.foreach(&vm->vm, base, base + sz, insert_pte, &d);
+	}
+
+	return &vm->vm;
+
+err_vm:
+	i915_vm_put(&vm->vm);
+	return ERR_PTR(err);
+}
+
+static struct intel_engine_cs *first_copy_engine(struct intel_gt *gt)
+{
+	struct intel_engine_cs *engine;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(gt->engine_class[COPY_ENGINE_CLASS]); i++) {
+		engine = gt->engine_class[COPY_ENGINE_CLASS][i];
+		if (engine_supports_migration(engine))
+			return engine;
+	}
+
+	return NULL;
+}
+
+static struct intel_context *pinned_context(struct intel_gt *gt)
+{
+	static struct lock_class_key key;
+	struct intel_engine_cs *engine;
+	struct i915_address_space *vm;
+	struct intel_context *ce;
+
+	engine = first_copy_engine(gt);
+	if (!engine)
+		return ERR_PTR(-ENODEV);
+
+	vm = migrate_vm(gt);
+	if (IS_ERR(vm))
+		return ERR_CAST(vm);
+
+	ce = intel_engine_create_pinned_context(engine, vm, SZ_512K,
+						I915_GEM_HWS_MIGRATE,
+						&key, "migrate");
+	i915_vm_put(vm);
+	return ce;
+}
+
+int intel_migrate_init(struct intel_migrate *m, struct intel_gt *gt)
+{
+	struct intel_context *ce;
+
+	memset(m, 0, sizeof(*m));
+
+	ce = pinned_context(gt);
+	if (IS_ERR(ce))
+		return PTR_ERR(ce);
+
+	m->context = ce;
+	return 0;
+}
+
+static int random_index(unsigned int max)
+{
+	return upper_32_bits(mul_u32_u32(get_random_u32(), max));
+}
+
+static struct intel_context *__migrate_engines(struct intel_gt *gt)
+{
+	struct intel_engine_cs *engines[MAX_ENGINE_INSTANCE];
+	struct intel_engine_cs *engine;
+	unsigned int count, i;
+
+	count = 0;
+	for (i = 0; i < ARRAY_SIZE(gt->engine_class[COPY_ENGINE_CLASS]); i++) {
+		engine = gt->engine_class[COPY_ENGINE_CLASS][i];
+		if (engine_supports_migration(engine))
+			engines[count++] = engine;
+	}
+
+	return intel_context_create(engines[random_index(count)]);
+}
+
+struct intel_context *intel_migrate_create_context(struct intel_migrate *m)
+{
+	struct intel_context *ce;
+
+	/*
+	 * We randomly distribute contexts across the engines upon constrction,
+	 * as they all share the same pinned vm, and so in order to allow
+	 * multiple blits to run in parallel, we must construct each blit
+	 * to use a different range of the vm for its GTT. This has to be
+	 * known at construction, so we can not use the late greedy load
+	 * balancing of the virtual-engine.
+	 */
+	ce = __migrate_engines(m->context->engine->gt);
+	if (IS_ERR(ce))
+		return ce;
+
+	ce->ring = NULL;
+	ce->ring_size = SZ_256K;
+
+	i915_vm_put(ce->vm);
+	ce->vm = i915_vm_get(m->context->vm);
+
+	return ce;
+}
+
+static inline struct sgt_dma sg_sgt(struct scatterlist *sg)
+{
+	dma_addr_t addr = sg_dma_address(sg);
+
+	return (struct sgt_dma){ sg, addr, addr + sg_dma_len(sg) };
+}
+
+static int emit_no_arbitration(struct i915_request *rq)
+{
+	u32 *cs;
+
+	cs = intel_ring_begin(rq, 2);
+	if (IS_ERR(cs))
+		return PTR_ERR(cs);
+
+	/* Explicitly disable preemption for this request. */
+	*cs++ = MI_ARB_ON_OFF;
+	*cs++ = MI_NOOP;
+	intel_ring_advance(rq, cs);
+
+	return 0;
+}
+
+static int emit_pte(struct i915_request *rq,
+		    struct sgt_dma *it,
+		    enum i915_cache_level cache_level,
+		    bool is_lmem,
+		    u64 offset,
+		    int length)
+{
+	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;
+	u32 *hdr, *cs;
+	int pkt;
+
+	GEM_BUG_ON(GRAPHICS_VER(rq->engine->i915) < 8);
+
+	/* Compute the page directory offset for the target address range */
+	offset += (u64)rq->engine->instance << 32;
+	offset >>= 12;
+	offset *= sizeof(u64);
+	offset += 2 * CHUNK_SZ;
+
+	cs = intel_ring_begin(rq, 6);
+	if (IS_ERR(cs))
+		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, pkt, (ring->size - ring->emit) / sizeof(u32) + 5);
+
+	hdr = cs;
+	*cs++ = MI_STORE_DATA_IMM | REG_BIT(21); /* as qword elements */
+	*cs++ = lower_32_bits(offset);
+	*cs++ = upper_32_bits(offset);
+
+	do {
+		if (cs - hdr >= pkt) {
+			*hdr += cs - hdr - 2;
+			*cs++ = MI_NOOP;
+
+			ring->emit = (void *)cs - ring->vaddr;
+			intel_ring_advance(rq, cs);
+			intel_ring_update_space(ring);
+
+			cs = intel_ring_begin(rq, 6);
+			if (IS_ERR(cs))
+				return PTR_ERR(cs);
+
+			pkt = min_t(int, 0x400, ring->space / sizeof(u32) + 5);
+			pkt = min_t(int, pkt, (ring->size - ring->emit) / sizeof(u32) + 5);
+
+			hdr = cs;
+			*cs++ = MI_STORE_DATA_IMM | REG_BIT(21);
+			*cs++ = lower_32_bits(offset);
+			*cs++ = upper_32_bits(offset);
+		}
+
+		*cs++ = lower_32_bits(encode | it->dma);
+		*cs++ = upper_32_bits(encode | it->dma);
+
+		offset += 8;
+		total += I915_GTT_PAGE_SIZE;
+
+		it->dma += I915_GTT_PAGE_SIZE;
+		if (it->dma >= it->max) {
+			it->sg = __sg_next(it->sg);
+			if (!it->sg || sg_dma_len(it->sg) == 0)
+				break;
+
+			it->dma = sg_dma_address(it->sg);
+			it->max = it->dma + sg_dma_len(it->sg);
+		}
+	} while (total < length);
+
+	*hdr += cs - hdr - 2;
+	*cs++ = MI_NOOP;
+
+	ring->emit = (void *)cs - ring->vaddr;
+	intel_ring_advance(rq, cs);
+	intel_ring_update_space(ring);
+
+	return total;
+}
+
+static bool wa_1209644611_applies(int ver, u32 size)
+{
+	u32 height = size >> PAGE_SHIFT;
+
+	if (ver != 11)
+		return false;
+
+	return height % 4 == 3 && height <= 8;
+}
+
+static int emit_copy(struct i915_request *rq, int size)
+{
+	const int ver = GRAPHICS_VER(rq->engine->i915);
+	u32 instance = rq->engine->instance;
+	u32 *cs;
+
+	cs = intel_ring_begin(rq, ver >= 8 ? 10 : 6);
+	if (IS_ERR(cs))
+		return PTR_ERR(cs);
+
+	if (ver >= 9 && !wa_1209644611_applies(ver, size)) {
+		*cs++ = GEN9_XY_FAST_COPY_BLT_CMD | (10 - 2);
+		*cs++ = BLT_DEPTH_32 | PAGE_SIZE;
+		*cs++ = 0;
+		*cs++ = size >> PAGE_SHIFT << 16 | PAGE_SIZE / 4;
+		*cs++ = CHUNK_SZ; /* dst offset */
+		*cs++ = instance;
+		*cs++ = 0;
+		*cs++ = PAGE_SIZE;
+		*cs++ = 0; /* 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++ = instance;
+		*cs++ = 0;
+		*cs++ = PAGE_SIZE;
+		*cs++ = 0; /* 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++ = PAGE_SIZE;
+		*cs++ = 0; /* src offset */
+	}
+
+	intel_ring_advance(rq, cs);
+	return 0;
+}
+
+int
+intel_context_migrate_copy(struct intel_context *ce,
+			   struct dma_fence *await,
+			   struct scatterlist *src,
+			   enum i915_cache_level src_cache_level,
+			   bool src_is_lmem,
+			   struct scatterlist *dst,
+			   enum i915_cache_level dst_cache_level,
+			   bool dst_is_lmem,
+			   struct i915_request **out)
+{
+	struct sgt_dma it_src = sg_sgt(src), it_dst = sg_sgt(dst);
+	struct i915_request *rq;
+	int err;
+
+	GEM_BUG_ON(ce->vm != ce->engine->gt->migrate.context->vm);
+	*out = NULL;
+
+	GEM_BUG_ON(ce->ring->size < SZ_64K);
+
+	do {
+		int len;
+
+		rq = i915_request_create(ce);
+		if (IS_ERR(rq)) {
+			err = PTR_ERR(rq);
+			goto out_ce;
+		}
+
+		if (await) {
+			err = i915_request_await_dma_fence(rq, await);
+			if (err)
+				goto out_rq;
+
+			if (rq->engine->emit_init_breadcrumb) {
+				err = rq->engine->emit_init_breadcrumb(rq);
+				if (err)
+					goto out_rq;
+			}
+
+			await = NULL;
+		}
+
+		/* The PTE updates + copy must not be interrupted. */
+		err = emit_no_arbitration(rq);
+		if (err)
+			goto out_rq;
+
+		len = emit_pte(rq, &it_src, src_cache_level, src_is_lmem, 0,
+			       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);
+		if (err < 0)
+			goto out_rq;
+		if (err < len) {
+			err = -EINVAL;
+			goto out_rq;
+		}
+
+		err = rq->engine->emit_flush(rq, EMIT_INVALIDATE);
+		if (err)
+			goto out_rq;
+
+		err = emit_copy(rq, len);
+
+		/* Arbitration is re-enabled between requests. */
+out_rq:
+		if (*out)
+			i915_request_put(*out);
+		*out = i915_request_get(rq);
+		i915_request_add(rq);
+		if (err || !it_src.sg || !sg_dma_len(it_src.sg))
+			break;
+
+		cond_resched();
+	} while (1);
+
+out_ce:
+	return err;
+}
+
+static int emit_clear(struct i915_request *rq, 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);
+
+	cs = intel_ring_begin(rq, ver >= 8 ? 8 : 6);
+	if (IS_ERR(cs))
+		return PTR_ERR(cs);
+
+	if (ver >= 8) {
+		*cs++ = XY_COLOR_BLT_CMD | BLT_WRITE_RGBA | (7 - 2);
+		*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++ = value;
+		*cs++ = MI_NOOP;
+	} else {
+		GEM_BUG_ON(instance);
+		*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++ = value;
+	}
+
+	intel_ring_advance(rq, cs);
+	return 0;
+}
+
+int
+intel_context_migrate_clear(struct intel_context *ce,
+			    struct dma_fence *await,
+			    struct scatterlist *sg,
+			    enum i915_cache_level cache_level,
+			    bool is_lmem,
+			    u32 value,
+			    struct i915_request **out)
+{
+	struct sgt_dma it = sg_sgt(sg);
+	struct i915_request *rq;
+	int err;
+
+	GEM_BUG_ON(ce->vm != ce->engine->gt->migrate.context->vm);
+	*out = NULL;
+
+	GEM_BUG_ON(ce->ring->size < SZ_64K);
+
+	do {
+		int len;
+
+		rq = i915_request_create(ce);
+		if (IS_ERR(rq)) {
+			err = PTR_ERR(rq);
+			goto out_ce;
+		}
+
+		if (await) {
+			err = i915_request_await_dma_fence(rq, await);
+			if (err)
+				goto out_rq;
+
+			if (rq->engine->emit_init_breadcrumb) {
+				err = rq->engine->emit_init_breadcrumb(rq);
+				if (err)
+					goto out_rq;
+			}
+
+			await = NULL;
+		}
+
+		/* The PTE updates + clear must not be interrupted. */
+		err = emit_no_arbitration(rq);
+		if (err)
+			goto out_rq;
+
+		len = emit_pte(rq, &it, cache_level, is_lmem, 0, CHUNK_SZ);
+		if (len <= 0) {
+			err = len;
+			goto out_rq;
+		}
+
+		err = rq->engine->emit_flush(rq, EMIT_INVALIDATE);
+		if (err)
+			goto out_rq;
+
+		err = emit_clear(rq, len, value);
+
+		/* Arbitration is re-enabled between requests. */
+out_rq:
+		if (*out)
+			i915_request_put(*out);
+		*out = i915_request_get(rq);
+		i915_request_add(rq);
+		if (err || !it.sg || !sg_dma_len(it.sg))
+			break;
+
+		cond_resched();
+	} while (1);
+
+out_ce:
+	return err;
+}
+
+int intel_migrate_copy(struct intel_migrate *m,
+		       struct i915_gem_ww_ctx *ww,
+		       struct dma_fence *await,
+		       struct scatterlist *src,
+		       enum i915_cache_level src_cache_level,
+		       bool src_is_lmem,
+		       struct scatterlist *dst,
+		       enum i915_cache_level dst_cache_level,
+		       bool dst_is_lmem,
+		       struct i915_request **out)
+{
+	struct intel_context *ce;
+	int err;
+
+	*out = NULL;
+	if (!m->context)
+		return -ENODEV;
+
+	ce = intel_migrate_create_context(m);
+	if (IS_ERR(ce))
+		ce = intel_context_get(m->context);
+	GEM_BUG_ON(IS_ERR(ce));
+
+	err = intel_context_pin_ww(ce, ww);
+	if (err)
+		goto out;
+
+	err = intel_context_migrate_copy(ce, await,
+					 src, src_cache_level, src_is_lmem,
+					 dst, dst_cache_level, dst_is_lmem,
+					 out);
+
+	intel_context_unpin(ce);
+out:
+	intel_context_put(ce);
+	return err;
+}
+
+int
+intel_migrate_clear(struct intel_migrate *m,
+		    struct i915_gem_ww_ctx *ww,
+		    struct dma_fence *await,
+		    struct scatterlist *sg,
+		    enum i915_cache_level cache_level,
+		    bool is_lmem,
+		    u32 value,
+		    struct i915_request **out)
+{
+	struct intel_context *ce;
+	int err;
+
+	*out = NULL;
+	if (!m->context)
+		return -ENODEV;
+
+	ce = intel_migrate_create_context(m);
+	if (IS_ERR(ce))
+		ce = intel_context_get(m->context);
+	GEM_BUG_ON(IS_ERR(ce));
+
+	err = intel_context_pin_ww(ce, ww);
+	if (err)
+		goto out;
+
+	err = intel_context_migrate_clear(ce, await, sg, cache_level,
+					  is_lmem, value, out);
+
+	intel_context_unpin(ce);
+out:
+	intel_context_put(ce);
+	return err;
+}
+
+void intel_migrate_fini(struct intel_migrate *m)
+{
+	struct intel_context *ce;
+
+	ce = fetch_and_zero(&m->context);
+	if (!ce)
+		return;
+
+	intel_engine_destroy_pinned_context(ce);
+}
+
+#if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
+#include "selftest_migrate.c"
+#endif