On Sat, Oct 25, 2025 at 02:04:07PM +0200, Thomas Hellström wrote:
> Enable migrating to foreign drm_pagemaps.
> 

Slightly better commit message ahead of merging.

> Signed-off-by: Thomas Hellström <[email protected]>
> ---
>  drivers/gpu/drm/xe/xe_svm.c      | 39 +++++++++++++++-----------------
>  drivers/gpu/drm/xe/xe_svm.h      |  8 +++----
>  drivers/gpu/drm/xe/xe_vm.c       | 19 ++++++----------
>  drivers/gpu/drm/xe/xe_vm_types.h |  6 ++---
>  4 files changed, 32 insertions(+), 40 deletions(-)
> 
> diff --git a/drivers/gpu/drm/xe/xe_svm.c b/drivers/gpu/drm/xe/xe_svm.c
> index d27cedeaf70c..36a6ac293e71 100644
> --- a/drivers/gpu/drm/xe/xe_svm.c
> +++ b/drivers/gpu/drm/xe/xe_svm.c
> @@ -1132,9 +1132,9 @@ static int __xe_svm_handle_pagefault(struct xe_vm *vm, 
> struct xe_vma *vma,
>       if (err)
>               return err;
>  
> -     dpagemap = xe_vma_resolve_pagemap(vma, tile);
> -     ctx.device_private_page_owner =
> -             xe_svm_private_page_owner(vm, !dpagemap && !ctx.devmem_only);
> +     dpagemap = ctx.devmem_only ? xe_tile_local_pagemap(tile) :
> +             xe_vma_resolve_pagemap(vma, tile);
> +     ctx.device_private_page_owner = xe_svm_private_page_owner(vm, 
> !dpagemap);
>       range = xe_svm_range_find_or_insert(vm, fault_addr, vma, &ctx);
>  
>       if (IS_ERR(range))
> @@ -1159,13 +1159,8 @@ static int __xe_svm_handle_pagefault(struct xe_vm *vm, 
> struct xe_vma *vma,
>           xe_svm_range_needs_migrate_to_vram(range, vma, !!dpagemap || 
> ctx.devmem_only)) {
>               ktime_t migrate_start = xe_svm_stats_ktime_get();
>  
> -             /* TODO : For multi-device dpagemap will be used to find the
> -              * remote tile and remote device. Will need to modify
> -              * xe_svm_alloc_vram to use dpagemap for future multi-device
> -              * support.
> -              */
>               xe_svm_range_migrate_count_stats_incr(gt, range);
> -             err = xe_svm_alloc_vram(tile, range, &ctx);
> +             err = xe_svm_alloc_vram(range, &ctx, dpagemap);
>               xe_svm_range_migrate_us_stats_incr(gt, range, migrate_start);
>               ctx.timeslice_ms <<= 1; /* Double timeslice if we have to retry 
> */
>               if (err) {
> @@ -1482,7 +1477,13 @@ u8 xe_svm_ranges_zap_ptes_in_range(struct xe_vm *vm, 
> u64 start, u64 end)
>   */
>  struct drm_pagemap *xe_vma_resolve_pagemap(struct xe_vma *vma, struct 
> xe_tile *tile)
>  {
> -     s32 fd = (s32)vma->attr.preferred_loc.devmem_fd;
> +     struct drm_pagemap *dpagemap = vma->attr.preferred_loc.dpagemap;
> +     s32 fd;
> +
> +     if (dpagemap)
> +             return dpagemap;
> +
> +     fd = (s32)vma->attr.preferred_loc.devmem_fd;
>  
>       if (fd == DRM_XE_PREFERRED_LOC_DEFAULT_SYSTEM)
>               return NULL;
> @@ -1490,28 +1491,24 @@ struct drm_pagemap *xe_vma_resolve_pagemap(struct 
> xe_vma *vma, struct xe_tile *t
>       if (fd == DRM_XE_PREFERRED_LOC_DEFAULT_DEVICE)
>               return IS_DGFX(tile_to_xe(tile)) ? xe_tile_local_pagemap(tile) 
> : NULL;
>  
> -     /* TODO: Support multi-device with drm_pagemap_from_fd(fd) */
>       return NULL;
>  }
>  
>  /**
>   * xe_svm_alloc_vram()- Allocate device memory pages for range,
>   * migrating existing data.
> - * @tile: tile to allocate vram from
>   * @range: SVM range
>   * @ctx: DRM GPU SVM context
> + * @dpagemap: The struct drm_pagemap representing the memory to allocate.
>   *
>   * Return: 0 on success, error code on failure.
>   */
> -int xe_svm_alloc_vram(struct xe_tile *tile, struct xe_svm_range *range,
> -                   const struct drm_gpusvm_ctx *ctx)
> +int xe_svm_alloc_vram(struct xe_svm_range *range, const struct 
> drm_gpusvm_ctx *ctx,
> +                   struct drm_pagemap *dpagemap)
>  {
> -     struct drm_pagemap *dpagemap;
> -
> -     xe_assert(tile_to_xe(tile), range->base.pages.flags.migrate_devmem);
> +     xe_assert(range_to_vm(&range->base)->xe, 
> range->base.pages.flags.migrate_devmem);
>       range_debug(range, "ALLOCATE VRAM");
>  
> -     dpagemap = xe_tile_local_pagemap(tile);
>       return drm_pagemap_populate_mm(dpagemap, xe_svm_range_start(range),
>                                      xe_svm_range_end(range),
>                                      range->base.gpusvm->mm,
> @@ -1778,9 +1775,9 @@ int xe_pagemap_cache_create(struct xe_tile *tile)
>       return 0;
>  }
>  
> -int xe_svm_alloc_vram(struct xe_tile *tile,
> -                   struct xe_svm_range *range,
> -                   const struct drm_gpusvm_ctx *ctx)
> +int xe_svm_alloc_vram(struct xe_svm_range *range,
> +                   const struct drm_gpusvm_ctx *ctx,
> +                   struct drm_pagemap *dpagemap)
>  {
>       return -EOPNOTSUPP;
>  }
> diff --git a/drivers/gpu/drm/xe/xe_svm.h b/drivers/gpu/drm/xe/xe_svm.h
> index 5adce108f7eb..c7027facf6e9 100644
> --- a/drivers/gpu/drm/xe/xe_svm.h
> +++ b/drivers/gpu/drm/xe/xe_svm.h
> @@ -94,8 +94,8 @@ int xe_svm_bo_evict(struct xe_bo *bo);
>  
>  void xe_svm_range_debug(struct xe_svm_range *range, const char *operation);
>  
> -int xe_svm_alloc_vram(struct xe_tile *tile, struct xe_svm_range *range,
> -                   const struct drm_gpusvm_ctx *ctx);
> +int xe_svm_alloc_vram(struct xe_svm_range *range, const struct 
> drm_gpusvm_ctx *ctx,
> +                   struct drm_pagemap *dpagemap);
>  
>  struct xe_svm_range *xe_svm_range_find_or_insert(struct xe_vm *vm, u64 addr,
>                                                struct xe_vma *vma, struct 
> drm_gpusvm_ctx *ctx);
> @@ -276,8 +276,8 @@ void xe_svm_range_debug(struct xe_svm_range *range, const 
> char *operation)
>  }
>  
>  static inline int
> -xe_svm_alloc_vram(struct xe_tile *tile, struct xe_svm_range *range,
> -               const struct drm_gpusvm_ctx *ctx)
> +xe_svm_alloc_vram(struct xe_svm_range *range, const struct drm_gpusvm_ctx 
> *ctx,
> +               struct drm_pagemap *dpagemap)
>  {
>       return -EOPNOTSUPP;
>  }
> diff --git a/drivers/gpu/drm/xe/xe_vm.c b/drivers/gpu/drm/xe/xe_vm.c
> index 3c3dc1b1ace9..381d4b4abac9 100644
> --- a/drivers/gpu/drm/xe/xe_vm.c
> +++ b/drivers/gpu/drm/xe/xe_vm.c
> @@ -2355,18 +2355,13 @@ vm_bind_ioctl_ops_create(struct xe_vm *vm, struct 
> xe_vma_ops *vops,
>                       if (prefetch_region == 
> DRM_XE_CONSULT_MEM_ADVISE_PREF_LOC) {
>                               dpagemap = xe_vma_resolve_pagemap(vma,
>                                                                 
> xe_device_get_root_tile(vm->xe));
> -                             /*
> -                              * TODO: Once multigpu support is enabled will 
> need
> -                              * something to dereference tile from dpagemap.
> -                              */
> -                             if (dpagemap)
> -                                     tile = xe_device_get_root_tile(vm->xe);
>                       } else if (prefetch_region) {
>                               tile = 
> &vm->xe->tiles[region_to_mem_type[prefetch_region] -
>                                                     XE_PL_VRAM0];
> +                             dpagemap = xe_tile_local_pagemap(tile);

Per kernel test robot, dpagemap needs to initialized to NULL. There is
existing code which tile to NULL after a for_each_tile loop that can
also be droppped.

Everything else looks right.

Matt

>                       }
>  
> -                     op->prefetch_range.tile = tile;
> +                     op->prefetch_range.dpagemap = dpagemap;
>  alloc_next_range:
>                       svm_range = xe_svm_range_find_or_insert(vm, addr, vma, 
> &ctx);
>  
> @@ -2897,7 +2892,7 @@ static int prefetch_ranges(struct xe_vm *vm, struct 
> xe_vma_op *op)
>  {
>       bool devmem_possible = IS_DGFX(vm->xe) && 
> IS_ENABLED(CONFIG_DRM_XE_PAGEMAP);
>       struct xe_vma *vma = gpuva_to_vma(op->base.prefetch.va);
> -     struct xe_tile *tile = op->prefetch_range.tile;
> +     struct drm_pagemap *dpagemap = op->prefetch_range.dpagemap;
>       int err = 0;
>  
>       struct xe_svm_range *svm_range;
> @@ -2910,15 +2905,15 @@ static int prefetch_ranges(struct xe_vm *vm, struct 
> xe_vma_op *op)
>       ctx.read_only = xe_vma_read_only(vma);
>       ctx.devmem_possible = devmem_possible;
>       ctx.check_pages_threshold = devmem_possible ? SZ_64K : 0;
> -     ctx.device_private_page_owner = xe_svm_private_page_owner(vm, !tile);
> +     ctx.device_private_page_owner = xe_svm_private_page_owner(vm, 
> !dpagemap);
>  
>       /* TODO: Threading the migration */
>       xa_for_each(&op->prefetch_range.range, i, svm_range) {
> -             if (!tile)
> +             if (!dpagemap)
>                       xe_svm_range_migrate_to_smem(vm, svm_range);
>  
> -             if (xe_svm_range_needs_migrate_to_vram(svm_range, vma, !!tile)) 
> {
> -                     err = xe_svm_alloc_vram(tile, svm_range, &ctx);
> +             if (xe_svm_range_needs_migrate_to_vram(svm_range, vma, 
> !!dpagemap)) {
> +                     err = xe_svm_alloc_vram(svm_range, &ctx, dpagemap);
>                       if (err) {
>                               drm_dbg(&vm->xe->drm, "VRAM allocation failed, 
> retry from userspace, asid=%u, gpusvm=%p, errno=%pe\n",
>                                       vm->usm.asid, &vm->svm.gpusvm, 
> ERR_PTR(err));
> diff --git a/drivers/gpu/drm/xe/xe_vm_types.h 
> b/drivers/gpu/drm/xe/xe_vm_types.h
> index 70856d536047..5313bf2afa54 100644
> --- a/drivers/gpu/drm/xe/xe_vm_types.h
> +++ b/drivers/gpu/drm/xe/xe_vm_types.h
> @@ -413,10 +413,10 @@ struct xe_vma_op_prefetch_range {
>       /** @ranges_count: number of svm ranges to map */
>       u32 ranges_count;
>       /**
> -      * @tile: Pointer to the tile structure containing memory to prefetch.
> -      *        NULL if prefetch requested region is smem
> +      * @dpagemap: Pointer to the dpagemap structure containing memory to 
> prefetch.
> +      * NULL if prefetch requested region is smem
>        */
> -     struct xe_tile *tile;
> +     struct drm_pagemap *dpagemap;
>  };
>  
>  /** enum xe_vma_op_flags - flags for VMA operation */
> -- 
> 2.51.0
> 

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