[PATCH v3 2/2] drm/xe: Unify the initialization of VRAM regions
Matthew Auld
matthew.auld at intel.com
Tue Jun 24 10:10:30 UTC 2025
On 24/06/2025 10:22, Piórkowski, Piotr wrote:
> From: Piotr Piórkowski <piotr.piorkowski at intel.com>
>
> Currently in the drivers we have defined VRAM regions per device and per
> tile. Initialization of these regions is done in two completely different
> ways. To simplify the logic of the code and make it easier to add new
> regions in the future, let's unify the way we initialize VRAM regions.
>
> v2:
> - fix doc comments in struct xe_vram_region
> - remove unnecessary includes (Jani)
> v3:
> - move code from xe_vram_init_regions_managers to xe_tile_init_noalloc
> (Matthew)
> - replace ioremap_wc to devm_ioremap_wc for mapping VRAM BAR
> (Matthew)
> - Replace the tile id parameter with vram region in the xe_pf_begin
> function.
>
> Signed-off-by: Piotr Piórkowski <piotr.piorkowski at intel.com>
> Cc: Stuart Summers <stuart.summers at intel.com>
> Cc: Matthew Auld <matthew.auld at intel.com>
> Cc: Jani Nikula <jani.nikula at intel.com>
> ---
> drivers/gpu/drm/xe/xe_device_types.h | 8 ++
> drivers/gpu/drm/xe/xe_gt_pagefault.c | 12 ++-
> drivers/gpu/drm/xe/xe_query.c | 2 +-
> drivers/gpu/drm/xe/xe_tile.c | 38 +++----
> drivers/gpu/drm/xe/xe_ttm_vram_mgr.c | 16 ++-
> drivers/gpu/drm/xe/xe_ttm_vram_mgr.h | 3 +-
> drivers/gpu/drm/xe/xe_vram.c | 148 ++++++++++++++++-----------
> drivers/gpu/drm/xe/xe_vram.h | 4 +
> 8 files changed, 135 insertions(+), 96 deletions(-)
>
> diff --git a/drivers/gpu/drm/xe/xe_device_types.h b/drivers/gpu/drm/xe/xe_device_types.h
> index a7bcda67d05f..e34a48d1312b 100644
> --- a/drivers/gpu/drm/xe/xe_device_types.h
> +++ b/drivers/gpu/drm/xe/xe_device_types.h
> @@ -76,6 +76,12 @@ struct xe_pxp;
> struct xe_vram_region {
> /** @tile: Backpointer to tile */
> struct xe_tile *tile;
> + /**
> + * @id: VRAM region instance id
> + *
> + * The value should be unique for VRAM region.
> + */
> + u8 id;
> /** @io_start: IO start address of this VRAM instance */
> resource_size_t io_start;
> /**
> @@ -108,6 +114,8 @@ struct xe_vram_region {
> void __iomem *mapping;
> /** @ttm: VRAM TTM manager */
> struct xe_ttm_vram_mgr ttm;
> + /** @placement: TTM placement dedicated for this region */
> + u32 placement;
> #if IS_ENABLED(CONFIG_DRM_XE_DEVMEM_MIRROR)
> /** @pagemap: Used to remap device memory as ZONE_DEVICE */
> struct dev_pagemap pagemap;
> diff --git a/drivers/gpu/drm/xe/xe_gt_pagefault.c b/drivers/gpu/drm/xe/xe_gt_pagefault.c
> index 3522865c67c9..a20ddab31c96 100644
> --- a/drivers/gpu/drm/xe/xe_gt_pagefault.c
> +++ b/drivers/gpu/drm/xe/xe_gt_pagefault.c
> @@ -74,7 +74,7 @@ static bool vma_is_valid(struct xe_tile *tile, struct xe_vma *vma)
> }
>
> static int xe_pf_begin(struct drm_exec *exec, struct xe_vma *vma,
> - bool atomic, unsigned int id)
> + bool atomic, struct xe_vram_region *vram)
> {
> struct xe_bo *bo = xe_vma_bo(vma);
> struct xe_vm *vm = xe_vma_vm(vma);
> @@ -84,14 +84,16 @@ static int xe_pf_begin(struct drm_exec *exec, struct xe_vma *vma,
> if (err)
> return err;
>
> - if (atomic && IS_DGFX(vm->xe)) {
> + if (atomic && vram) {
> + xe_assert(vm->xe, IS_DGFX(vm->xe));
> +
> if (xe_vma_is_userptr(vma)) {
> err = -EACCES;
> return err;
> }
>
> /* Migrate to VRAM, move should invalidate the VMA first */
> - err = xe_bo_migrate(bo, XE_PL_VRAM0 + id);
> + err = xe_bo_migrate(bo, vram->placement);
> if (err)
> return err;
> } else if (bo) {
> @@ -138,7 +140,7 @@ static int handle_vma_pagefault(struct xe_gt *gt, struct xe_vma *vma,
> /* Lock VM and BOs dma-resv */
> drm_exec_init(&exec, 0, 0);
> drm_exec_until_all_locked(&exec) {
> - err = xe_pf_begin(&exec, vma, atomic, tile->id);
> + err = xe_pf_begin(&exec, vma, atomic, tile->mem.vram);
> drm_exec_retry_on_contention(&exec);
> if (xe_vm_validate_should_retry(&exec, err, &end))
> err = -EAGAIN;
> @@ -572,7 +574,7 @@ static int handle_acc(struct xe_gt *gt, struct acc *acc)
> /* Lock VM and BOs dma-resv */
> drm_exec_init(&exec, 0, 0);
> drm_exec_until_all_locked(&exec) {
> - ret = xe_pf_begin(&exec, vma, true, tile->id);
> + ret = xe_pf_begin(&exec, vma, true, tile->mem.vram);
> drm_exec_retry_on_contention(&exec);
> if (ret)
> break;
> diff --git a/drivers/gpu/drm/xe/xe_query.c b/drivers/gpu/drm/xe/xe_query.c
> index ba9b7482605c..ffd2efffa7a3 100644
> --- a/drivers/gpu/drm/xe/xe_query.c
> +++ b/drivers/gpu/drm/xe/xe_query.c
> @@ -409,7 +409,7 @@ static int query_gt_list(struct xe_device *xe, struct drm_xe_device_query *query
> gt_list->gt_list[id].near_mem_regions = 0x1;
> else
> gt_list->gt_list[id].near_mem_regions =
> - BIT(gt_to_tile(gt)->id) << 1;
> + BIT(gt_to_tile(gt)->mem.vram->id) << 1;
> gt_list->gt_list[id].far_mem_regions = xe->info.mem_region_mask ^
> gt_list->gt_list[id].near_mem_regions;
>
> diff --git a/drivers/gpu/drm/xe/xe_tile.c b/drivers/gpu/drm/xe/xe_tile.c
> index c64a4d1a5bb9..3acd8e359070 100644
> --- a/drivers/gpu/drm/xe/xe_tile.c
> +++ b/drivers/gpu/drm/xe/xe_tile.c
> @@ -7,6 +7,7 @@
>
> #include <drm/drm_managed.h>
>
> +#include "xe_bo.h"
> #include "xe_device.h"
> #include "xe_ggtt.h"
> #include "xe_gt.h"
> @@ -18,6 +19,7 @@
> #include "xe_tile_sysfs.h"
> #include "xe_ttm_vram_mgr.h"
> #include "xe_wa.h"
> +#include "xe_vram.h"
>
> /**
> * DOC: Multi-tile Design
> @@ -111,11 +113,9 @@ int xe_tile_alloc_vram(struct xe_tile *tile)
> if (!IS_DGFX(xe))
> return 0;
>
> - vram = drmm_kzalloc(&xe->drm, sizeof(*vram), GFP_KERNEL);
> - if (!vram)
> - return -ENOMEM;
> -
> - vram->tile = tile;
> + vram = xe_vram_region_alloc(xe, tile->id, XE_PL_VRAM0 + tile->id);
> + if (IS_ERR(vram))
> + return PTR_ERR(vram);
> tile->mem.vram = vram;
>
> return 0;
> @@ -153,21 +153,6 @@ int xe_tile_init_early(struct xe_tile *tile, struct xe_device *xe, u8 id)
> }
> ALLOW_ERROR_INJECTION(xe_tile_init_early, ERRNO); /* See xe_pci_probe() */
>
> -static int tile_ttm_mgr_init(struct xe_tile *tile)
> -{
> - struct xe_device *xe = tile_to_xe(tile);
> - int err;
> -
> - if (tile->mem.vram->usable_size) {
> - err = xe_ttm_vram_mgr_init(tile, &tile->mem.vram->ttm);
> - if (err)
> - return err;
> - xe->info.mem_region_mask |= BIT(tile->id) << 1;
> - }
> -
> - return 0;
> -}
> -
> /**
> * xe_tile_init_noalloc - Init tile up to the point where allocations can happen.
> * @tile: The tile to initialize.
> @@ -185,17 +170,20 @@ static int tile_ttm_mgr_init(struct xe_tile *tile)
> int xe_tile_init_noalloc(struct xe_tile *tile)
> {
> struct xe_device *xe = tile_to_xe(tile);
> - int err;
> -
> - err = tile_ttm_mgr_init(tile);
> - if (err)
> - return err;
>
> xe_wa_apply_tile_workarounds(tile);
>
> if (xe->info.has_usm && IS_DGFX(xe))
> xe_devm_add(tile, tile->mem.vram);
>
> + if (IS_DGFX(xe) && !ttm_resource_manager_used(&tile->mem.vram->ttm.manager)) {
> + int err = xe_ttm_vram_mgr_init(xe, tile->mem.vram);
> +
> + if (err)
> + return err;
> + xe->info.mem_region_mask |= BIT(tile->mem.vram->id) << 1;
> + }
> +
> return xe_tile_sysfs_init(tile);
> }
>
> diff --git a/drivers/gpu/drm/xe/xe_ttm_vram_mgr.c b/drivers/gpu/drm/xe/xe_ttm_vram_mgr.c
> index d9afe0e22071..3a9780d39c65 100644
> --- a/drivers/gpu/drm/xe/xe_ttm_vram_mgr.c
> +++ b/drivers/gpu/drm/xe/xe_ttm_vram_mgr.c
> @@ -337,12 +337,18 @@ int __xe_ttm_vram_mgr_init(struct xe_device *xe, struct xe_ttm_vram_mgr *mgr,
> return drmm_add_action_or_reset(&xe->drm, ttm_vram_mgr_fini, mgr);
> }
>
> -int xe_ttm_vram_mgr_init(struct xe_tile *tile, struct xe_ttm_vram_mgr *mgr)
> +/**
> + * xe_ttm_vram_mgr_init - initialize TTM VRAM region
> + * @xe: pointer to Xe device
> + * @vram: pointer to xe_vram_region that contains the memory region attributes
> + *
> + * Initialize the Xe TTM for given @vram region using the given parameters.
> + *
> + * Returns 0 for success, negative error code otherwise.
> + */
> +int xe_ttm_vram_mgr_init(struct xe_device *xe, struct xe_vram_region *vram)
> {
> - struct xe_device *xe = tile_to_xe(tile);
> - struct xe_vram_region *vram = tile->mem.vram;
> -
> - return __xe_ttm_vram_mgr_init(xe, mgr, XE_PL_VRAM0 + tile->id,
> + return __xe_ttm_vram_mgr_init(xe, &vram->ttm, vram->placement,
> vram->usable_size, vram->io_size,
> PAGE_SIZE);
> }
> diff --git a/drivers/gpu/drm/xe/xe_ttm_vram_mgr.h b/drivers/gpu/drm/xe/xe_ttm_vram_mgr.h
> index cc76050e376d..87b7fae5edba 100644
> --- a/drivers/gpu/drm/xe/xe_ttm_vram_mgr.h
> +++ b/drivers/gpu/drm/xe/xe_ttm_vram_mgr.h
> @@ -11,11 +11,12 @@
> enum dma_data_direction;
> struct xe_device;
> struct xe_tile;
> +struct xe_vram_region;
>
> int __xe_ttm_vram_mgr_init(struct xe_device *xe, struct xe_ttm_vram_mgr *mgr,
> u32 mem_type, u64 size, u64 io_size,
> u64 default_page_size);
> -int xe_ttm_vram_mgr_init(struct xe_tile *tile, struct xe_ttm_vram_mgr *mgr);
> +int xe_ttm_vram_mgr_init(struct xe_device *xe, struct xe_vram_region *vram);
> int xe_ttm_vram_mgr_alloc_sgt(struct xe_device *xe,
> struct ttm_resource *res,
> u64 offset, u64 length,
> diff --git a/drivers/gpu/drm/xe/xe_vram.c b/drivers/gpu/drm/xe/xe_vram.c
> index 18124a5fb291..e35b4dda9172 100644
> --- a/drivers/gpu/drm/xe/xe_vram.c
> +++ b/drivers/gpu/drm/xe/xe_vram.c
> @@ -19,6 +19,7 @@
> #include "xe_mmio.h"
> #include "xe_module.h"
> #include "xe_sriov.h"
> +#include "xe_ttm_vram_mgr.h"
> #include "xe_vram.h"
>
> #define BAR_SIZE_SHIFT 20
> @@ -136,7 +137,7 @@ static bool resource_is_valid(struct pci_dev *pdev, int bar)
> return true;
> }
>
> -static int determine_lmem_bar_size(struct xe_device *xe)
> +static int determine_lmem_bar_size(struct xe_device *xe, struct xe_vram_region *lmem_bar)
> {
> struct pci_dev *pdev = to_pci_dev(xe->drm.dev);
>
> @@ -147,16 +148,16 @@ static int determine_lmem_bar_size(struct xe_device *xe)
>
> resize_vram_bar(xe);
>
> - xe->mem.vram->io_start = pci_resource_start(pdev, LMEM_BAR);
> - xe->mem.vram->io_size = pci_resource_len(pdev, LMEM_BAR);
> - if (!xe->mem.vram->io_size)
> + lmem_bar->io_start = pci_resource_start(pdev, LMEM_BAR);
> + lmem_bar->io_size = pci_resource_len(pdev, LMEM_BAR);
> + if (!lmem_bar->io_size)
> return -EIO;
>
> /* XXX: Need to change when xe link code is ready */
> - xe->mem.vram->dpa_base = 0;
> + lmem_bar->dpa_base = 0;
>
> /* set up a map to the total memory area. */
> - xe->mem.vram->mapping = ioremap_wc(xe->mem.vram->io_start, xe->mem.vram->io_size);
> + lmem_bar->mapping = devm_ioremap_wc(&pdev->dev, lmem_bar->io_start, lmem_bar->io_size);
Nice. I think in vram_fini() we can now also drop the manual iounmap()?
You could also potentially make the s/ioremap_wc/devm_ioremap_wc/ a
seperate change at the start of the series, since this technically fixes
an existing issue, plus as a standalone change is an improvement. Up to
you though.
>
> return 0;
> }
> @@ -287,6 +288,65 @@ static void vram_fini(void *arg)
> tile->mem.vram->mapping = NULL;
> }
>
> +struct xe_vram_region *xe_vram_region_alloc(struct xe_device *xe, u8 id, u32 placement)
> +{
> + struct xe_vram_region *vram;
> + struct drm_device *drm = &xe->drm;
> +
> + xe_assert(xe, id < xe->info.tile_count);
> +
> + vram = drmm_kzalloc(drm, sizeof(*vram), GFP_KERNEL);
> + if (!vram)
> + return NULL;
> +
> + vram->id = id;
> + vram->placement = placement;
> + vram->tile = &xe->tiles[id];
> +
> + return vram;
> +}
> +
> +static void print_vram_region_info(struct xe_device *xe, struct xe_vram_region *vram)
> +{
> + struct drm_device *drm = &xe->drm;
> +
> + if (vram->io_size < vram->usable_size)
> + drm_info(drm, "Small BAR device\n");
> +
> + drm_info(drm,
> + "VRAM[%u]: Actual physical size %pa, usable size exclude stolen %pa, CPU accessible size %pa\n",
> + vram->id, &vram->actual_physical_size, &vram->usable_size, &vram->io_size);
> + drm_info(drm, "VRAM[%u]: DPA range: [%pa-%llx], io range: [%pa-%llx]\n",
> + vram->id, &vram->dpa_base, vram->dpa_base + (u64)vram->actual_physical_size,
> + &vram->io_start, vram->io_start + (u64)vram->io_size);
> +}
> +
> +static int vram_region_init(struct xe_device *xe, struct xe_vram_region *vram,
> + struct xe_vram_region *lmem_bar, u64 offset, u64 usable_size,
> + u64 region_size, resource_size_t remain_io_size)
> +{
> + /* Check if VRAM region is already initialized */
> + if (vram->mapping)
> + return 0;
> +
> + vram->actual_physical_size = region_size;
> + vram->io_start = lmem_bar->io_start + offset;
> + vram->io_size = min_t(u64, usable_size, remain_io_size);
> +
> + if (!vram->io_size) {
> + drm_err(&xe->drm, "Tile without any CPU visible VRAM. Aborting.\n");
> + return -ENODEV;
> + }
> +
> + vram->dpa_base = lmem_bar->dpa_base + offset;
> + vram->mapping = lmem_bar->mapping + offset;
> + vram->usable_size = usable_size;
> +
> + print_vram_region_info(xe, vram);
> +
> + return 0;
> +}
> +
> /**
> * xe_vram_probe() - Probe VRAM configuration
> * @xe: the &xe_device
> @@ -298,82 +358,52 @@ static void vram_fini(void *arg)
> int xe_vram_probe(struct xe_device *xe)
> {
> struct xe_tile *tile;
> - resource_size_t io_size;
> + struct xe_vram_region lmem_bar;
> + resource_size_t remain_io_size;
> u64 available_size = 0;
> u64 total_size = 0;
> - u64 tile_offset;
> - u64 tile_size;
> - u64 vram_size;
> int err;
> u8 id;
>
> if (!IS_DGFX(xe))
> return 0;
>
> - /* Get the size of the root tile's vram for later accessibility comparison */
> - tile = xe_device_get_root_tile(xe);
> - err = tile_vram_size(tile, &vram_size, &tile_size, &tile_offset);
> - if (err)
> - return err;
> -
> - err = determine_lmem_bar_size(xe);
> + err = determine_lmem_bar_size(xe, &lmem_bar);
> if (err)
> return err;
> + drm_info(&xe->drm, "VISIBLE VRAM: %pa, %pa\n", &lmem_bar.io_start, &lmem_bar.io_size);
>
> - drm_info(&xe->drm, "VISIBLE VRAM: %pa, %pa\n", &xe->mem.vram->io_start,
> - &xe->mem.vram->io_size);
> + remain_io_size = lmem_bar.io_size;
>
> - io_size = xe->mem.vram->io_size;
> -
> - /* tile specific ranges */
> for_each_tile(tile, xe, id) {
> - err = tile_vram_size(tile, &vram_size, &tile_size, &tile_offset);
> + u64 region_size;
> + u64 usable_size;
> + u64 tile_offset;
> +
> + err = tile_vram_size(tile, &usable_size, ®ion_size, &tile_offset);
> if (err)
> return err;
>
> - tile->mem.vram->actual_physical_size = tile_size;
> - tile->mem.vram->io_start = xe->mem.vram->io_start + tile_offset;
> - tile->mem.vram->io_size = min_t(u64, vram_size, io_size);
> + total_size += region_size;
> + available_size += usable_size;
>
> - if (!tile->mem.vram->io_size) {
> - drm_err(&xe->drm, "Tile without any CPU visible VRAM. Aborting.\n");
> - return -ENODEV;
> - }
> + err = vram_region_init(xe, tile->mem.vram, &lmem_bar, tile_offset, usable_size,
> + region_size, remain_io_size);
> + if (err)
> + return err;
>
> - tile->mem.vram->dpa_base = xe->mem.vram->dpa_base + tile_offset;
> - tile->mem.vram->usable_size = vram_size;
> - tile->mem.vram->mapping = xe->mem.vram->mapping + tile_offset;
> -
> - if (tile->mem.vram->io_size < tile->mem.vram->usable_size)
> - drm_info(&xe->drm, "Small BAR device\n");
> - drm_info(&xe->drm,
> - "VRAM[%u, %u]: Actual physical size %pa, usable size exclude stolen %pa, CPU accessible size %pa\n",
> - id, tile->id, &tile->mem.vram->actual_physical_size,
> - &tile->mem.vram->usable_size, &tile->mem.vram->io_size);
> - drm_info(&xe->drm, "VRAM[%u, %u]: DPA range: [%pa-%llx], io range: [%pa-%llx]\n",
> - id, tile->id, &tile->mem.vram->dpa_base,
> - tile->mem.vram->dpa_base + (u64)tile->mem.vram->actual_physical_size,
> - &tile->mem.vram->io_start,
> - tile->mem.vram->io_start + (u64)tile->mem.vram->io_size);
> -
> - /* calculate total size using tile size to get the correct HW sizing */
> - total_size += tile_size;
> - available_size += vram_size;
> -
> - if (total_size > xe->mem.vram->io_size) {
> + if (total_size > lmem_bar.io_size) {
> drm_info(&xe->drm, "VRAM: %pa is larger than resource %pa\n",
> - &total_size, &xe->mem.vram->io_size);
> + &total_size, &lmem_bar.io_size);
> }
>
> - io_size -= min_t(u64, tile_size, io_size);
> + remain_io_size -= min_t(u64, tile->mem.vram->actual_physical_size, remain_io_size);
> }
>
> - xe->mem.vram->actual_physical_size = total_size;
> -
> - drm_info(&xe->drm, "Total VRAM: %pa, %pa\n", &xe->mem.vram->io_start,
> - &xe->mem.vram->actual_physical_size);
> - drm_info(&xe->drm, "Available VRAM: %pa, %pa\n", &xe->mem.vram->io_start,
> - &available_size);
> + err = vram_region_init(xe, xe->mem.vram, &lmem_bar, 0, available_size, total_size,
> + lmem_bar.io_size);
> + if (err)
> + return err;
>
> return devm_add_action_or_reset(xe->drm.dev, vram_fini, xe);
> }
> diff --git a/drivers/gpu/drm/xe/xe_vram.h b/drivers/gpu/drm/xe/xe_vram.h
> index e31cc04ec0db..4fc0bc1df4ce 100644
> --- a/drivers/gpu/drm/xe/xe_vram.h
> +++ b/drivers/gpu/drm/xe/xe_vram.h
> @@ -6,8 +6,12 @@
> #ifndef _XE_VRAM_H_
> #define _XE_VRAM_H_
>
> +#include <linux/types.h>
> +
> struct xe_device;
> +struct xe_vram_region;
>
> +struct xe_vram_region *xe_vram_region_alloc(struct xe_device *xe, u8 id, u32 placement);
> int xe_vram_probe(struct xe_device *xe);
>
> #endif
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