drm/xe/migrate: Add function to copy of VRAM data in chunks

Introduce a new function to copy data between VRAM and sysmem objects.
The existing xe_migrate_copy() is tailored for eviction and restore
operations, which involves additional logic and operates on entire
objects.
The xe_migrate_vram_copy_chunk() allows copying chunks of data to or
from a dedicated buffer object, which is essential in case of VF
migration.

Signed-off-by: Lukasz Laguna <lukasz.laguna@intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Link: https://patch.msgid.link/20251112132220.516975-22-michal.winiarski@intel.com
Signed-off-by: Michał Winiarski <michal.winiarski@intel.com>

Author: lukaszlaguna

drivers/gpu/drm/xe/xe_migrate.c

@@ -29,6 +29,7 @@
 #include "xe_lrc.h"
 #include "xe_map.h"
 #include "xe_mocs.h"
+#include "xe_printk.h"
 #include "xe_pt.h"
 #include "xe_res_cursor.h"
 #include "xe_sa.h"
@@ -1210,6 +1211,128 @@ struct xe_exec_queue *xe_migrate_exec_queue(struct xe_migrate *migrate)
 	return migrate->q;
 }
 
+/**
+ * xe_migrate_vram_copy_chunk() - Copy a chunk of a VRAM buffer object.
+ * @vram_bo: The VRAM buffer object.
+ * @vram_offset: The VRAM offset.
+ * @sysmem_bo: The sysmem buffer object.
+ * @sysmem_offset: The sysmem offset.
+ * @size: The size of VRAM chunk to copy.
+ * @dir: The direction of the copy operation.
+ *
+ * Copies a portion of a buffer object between VRAM and system memory.
+ * On Xe2 platforms that support flat CCS, VRAM data is decompressed when
+ * copying to system memory.
+ *
+ * Return: Pointer to a dma_fence representing the last copy batch, or
+ * an error pointer on failure. If there is a failure, any copy operation
+ * started by the function call has been synced.
+ */
+struct dma_fence *xe_migrate_vram_copy_chunk(struct xe_bo *vram_bo, u64 vram_offset,
+					     struct xe_bo *sysmem_bo, u64 sysmem_offset,
+					     u64 size, enum xe_migrate_copy_dir dir)
+{
+	struct xe_device *xe = xe_bo_device(vram_bo);
+	struct xe_tile *tile = vram_bo->tile;
+	struct xe_gt *gt = tile->primary_gt;
+	struct xe_migrate *m = tile->migrate;
+	struct dma_fence *fence = NULL;
+	struct ttm_resource *vram = vram_bo->ttm.resource;
+	struct ttm_resource *sysmem = sysmem_bo->ttm.resource;
+	struct xe_res_cursor vram_it, sysmem_it;
+	u64 vram_L0_ofs, sysmem_L0_ofs;
+	u32 vram_L0_pt, sysmem_L0_pt;
+	u64 vram_L0, sysmem_L0;
+	bool to_sysmem = (dir == XE_MIGRATE_COPY_TO_SRAM);
+	bool use_comp_pat = to_sysmem &&
+		GRAPHICS_VER(xe) >= 20 && xe_device_has_flat_ccs(xe);
+	int pass = 0;
+	int err;
+
+	xe_assert(xe, IS_ALIGNED(vram_offset | sysmem_offset | size, PAGE_SIZE));
+	xe_assert(xe, xe_bo_is_vram(vram_bo));
+	xe_assert(xe, !xe_bo_is_vram(sysmem_bo));
+	xe_assert(xe, !range_overflows(vram_offset, size, (u64)vram_bo->ttm.base.size));
+	xe_assert(xe, !range_overflows(sysmem_offset, size, (u64)sysmem_bo->ttm.base.size));
+
+	xe_res_first(vram, vram_offset, size, &vram_it);
+	xe_res_first_sg(xe_bo_sg(sysmem_bo), sysmem_offset, size, &sysmem_it);
+
+	while (size) {
+		u32 pte_flags = PTE_UPDATE_FLAG_IS_VRAM;
+		u32 batch_size = 2; /* arb_clear() + MI_BATCH_BUFFER_END */
+		struct xe_sched_job *job;
+		struct xe_bb *bb;
+		u32 update_idx;
+		bool usm = xe->info.has_usm;
+		u32 avail_pts = max_mem_transfer_per_pass(xe) / LEVEL0_PAGE_TABLE_ENCODE_SIZE;
+
+		sysmem_L0 = xe_migrate_res_sizes(m, &sysmem_it);
+		vram_L0 = min(xe_migrate_res_sizes(m, &vram_it), sysmem_L0);
+
+		xe_dbg(xe, "Pass %u, size: %llu\n", pass++, vram_L0);
+
+		pte_flags |= use_comp_pat ? PTE_UPDATE_FLAG_IS_COMP_PTE : 0;
+		batch_size += pte_update_size(m, pte_flags, vram, &vram_it, &vram_L0,
+					      &vram_L0_ofs, &vram_L0_pt, 0, 0, avail_pts);
+
+		batch_size += pte_update_size(m, 0, sysmem, &sysmem_it, &vram_L0, &sysmem_L0_ofs,
+					      &sysmem_L0_pt, 0, avail_pts, avail_pts);
+		batch_size += EMIT_COPY_DW;
+
+		bb = xe_bb_new(gt, batch_size, usm);
+		if (IS_ERR(bb)) {
+			err = PTR_ERR(bb);
+			return ERR_PTR(err);
+		}
+
+		if (xe_migrate_allow_identity(vram_L0, &vram_it))
+			xe_res_next(&vram_it, vram_L0);
+		else
+			emit_pte(m, bb, vram_L0_pt, true, use_comp_pat, &vram_it, vram_L0, vram);
+
+		emit_pte(m, bb, sysmem_L0_pt, false, false, &sysmem_it, vram_L0, sysmem);
+
+		bb->cs[bb->len++] = MI_BATCH_BUFFER_END;
+		update_idx = bb->len;
+
+		if (to_sysmem)
+			emit_copy(gt, bb, vram_L0_ofs, sysmem_L0_ofs, vram_L0, XE_PAGE_SIZE);
+		else
+			emit_copy(gt, bb, sysmem_L0_ofs, vram_L0_ofs, vram_L0, XE_PAGE_SIZE);
+
+		job = xe_bb_create_migration_job(m->q, bb, xe_migrate_batch_base(m, usm),
+						 update_idx);
+		if (IS_ERR(job)) {
+			xe_bb_free(bb, NULL);
+			err = PTR_ERR(job);
+			return ERR_PTR(err);
+		}
+
+		xe_sched_job_add_migrate_flush(job, MI_INVALIDATE_TLB);
+
+		xe_assert(xe, dma_resv_test_signaled(vram_bo->ttm.base.resv,
+						     DMA_RESV_USAGE_BOOKKEEP));
+		xe_assert(xe, dma_resv_test_signaled(sysmem_bo->ttm.base.resv,
+						     DMA_RESV_USAGE_BOOKKEEP));
+
+		scoped_guard(mutex, &m->job_mutex) {
+			xe_sched_job_arm(job);
+			dma_fence_put(fence);
+			fence = dma_fence_get(&job->drm.s_fence->finished);
+			xe_sched_job_push(job);
+
+			dma_fence_put(m->fence);
+			m->fence = dma_fence_get(fence);
+		}
+
+		xe_bb_free(bb, fence);
+		size -= vram_L0;
+	}
+
+	return fence;
+}
+
 static void emit_clear_link_copy(struct xe_gt *gt, struct xe_bb *bb, u64 src_ofs,
 				 u32 size, u32 pitch)
 {
@@ -1912,11 +2035,6 @@ static bool xe_migrate_vram_use_pde(struct drm_pagemap_addr *sram_addr,
 	return true;
 }
 
-enum xe_migrate_copy_dir {
-	XE_MIGRATE_COPY_TO_VRAM,
-	XE_MIGRATE_COPY_TO_SRAM,
-};
-
 #define XE_CACHELINE_BYTES	64ull
 #define XE_CACHELINE_MASK	(XE_CACHELINE_BYTES - 1)
 

drivers/gpu/drm/xe/xe_migrate.h

@@ -28,6 +28,11 @@ struct xe_vma;
 
 enum xe_sriov_vf_ccs_rw_ctxs;
 
+enum xe_migrate_copy_dir {
+	XE_MIGRATE_COPY_TO_VRAM,
+	XE_MIGRATE_COPY_TO_SRAM,
+};
+
 /**
  * struct xe_migrate_pt_update_ops - Callbacks for the
  * xe_migrate_update_pgtables() function.
@@ -131,6 +136,9 @@ int xe_migrate_ccs_rw_copy(struct xe_tile *tile, struct xe_exec_queue *q,
 
 struct xe_lrc *xe_migrate_lrc(struct xe_migrate *migrate);
 struct xe_exec_queue *xe_migrate_exec_queue(struct xe_migrate *migrate);
+struct dma_fence *xe_migrate_vram_copy_chunk(struct xe_bo *vram_bo, u64 vram_offset,
+					     struct xe_bo *sysmem_bo, u64 sysmem_offset,
+					     u64 size, enum xe_migrate_copy_dir dir);
 int xe_migrate_access_memory(struct xe_migrate *m, struct xe_bo *bo,
 			     unsigned long offset, void *buf, int len,
 			     int write);