On Thu, Oct 30, 2025 at 09:31:28PM +0100, Michał Winiarski wrote:
> From: Lukasz Laguna <[email protected]>
> 
> 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 <[email protected]>
> Signed-off-by: Michał Winiarski <[email protected]>

Reviewed-by: Matthew Brost <[email protected]>

> ---
>  drivers/gpu/drm/xe/xe_migrate.c | 128 ++++++++++++++++++++++++++++++--
>  drivers/gpu/drm/xe/xe_migrate.h |   8 ++
>  2 files changed, 131 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/gpu/drm/xe/xe_migrate.c b/drivers/gpu/drm/xe/xe_migrate.c
> index 56a5804726e96..dbe9320863ab0 100644
> --- a/drivers/gpu/drm/xe/xe_migrate.c
> +++ b/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)
>  
> diff --git a/drivers/gpu/drm/xe/xe_migrate.h b/drivers/gpu/drm/xe/xe_migrate.h
> index 4fad324b62535..d7bcc6ad8464e 100644
> --- a/drivers/gpu/drm/xe/xe_migrate.h
> +++ b/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);
> -- 
> 2.50.1
> 

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