On Wed, 2025-01-29 at 11:52 -0800, Matthew Brost wrote:
> Add SVM device memory mirroring which enables device pages for
> migration. Enabled via CONFIG_XE_DEVMEM_MIRROR Kconfig. Kconfig
> option
> defaults to enabled. If not enabled, SVM will work sans migration and
> KMD memory footprint will be less.
>
> v3:
> - Add CONFIG_XE_DEVMEM_MIRROR
> v4:
> - Fix Kconfig (Himal)
> - Use %pe to print errors (Thomas)
> - Fix alignment issue (Checkpatch)
>
> Signed-off-by: Niranjana Vishwanathapura
> <niranjana.vishwanathapura@xxxxxxxxx>
> Signed-off-by: Oak Zeng <oak.zeng@xxxxxxxxx>
> Signed-off-by: Matthew Brost <matthew.brost@xxxxxxxxx>
Reviewed-by: Thomas Hellström <thomas.hellstrom@xxxxxxxxxxxxxxx>
> ---
> drivers/gpu/drm/xe/Kconfig | 9 ++++
> drivers/gpu/drm/xe/xe_device_types.h | 8 ++++
> drivers/gpu/drm/xe/xe_svm.c | 62
> +++++++++++++++++++++++++++-
> drivers/gpu/drm/xe/xe_svm.h | 3 ++
> drivers/gpu/drm/xe/xe_tile.c | 5 +++
> 5 files changed, 85 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/xe/Kconfig b/drivers/gpu/drm/xe/Kconfig
> index 60b922f75001..4bc03d6f6720 100644
> --- a/drivers/gpu/drm/xe/Kconfig
> +++ b/drivers/gpu/drm/xe/Kconfig
> @@ -74,6 +74,15 @@ config DRM_XE_DP_TUNNEL
>
> If in doubt say "Y".
>
> +config DRM_XE_DEVMEM_MIRROR
> + bool "Enable device memory mirror"
> + depends on DRM_XE
> + select GET_FREE_REGION
> + default y
> + help
> + Disable this option only if you want to compile out
> without device
> + memory mirror. Will reduce KMD memory footprint when
> disabled.
> +
> config DRM_XE_FORCE_PROBE
> string "Force probe xe for selected Intel hardware IDs"
> depends on DRM_XE
> diff --git a/drivers/gpu/drm/xe/xe_device_types.h
> b/drivers/gpu/drm/xe/xe_device_types.h
> index 71151532e28f..da5bf145324b 100644
> --- a/drivers/gpu/drm/xe/xe_device_types.h
> +++ b/drivers/gpu/drm/xe/xe_device_types.h
> @@ -104,6 +104,14 @@ struct xe_mem_region {
> resource_size_t actual_physical_size;
> /** @mapping: pointer to VRAM mappable space */
> void __iomem *mapping;
> + /** @pagemap: Used to remap device memory as ZONE_DEVICE */
> + struct dev_pagemap pagemap;
> + /**
> + * @hpa_base: base host physical address
> + *
> + * This is generated when remap device memory as ZONE_DEVICE
> + */
> + resource_size_t hpa_base;
> };
>
> /**
> diff --git a/drivers/gpu/drm/xe/xe_svm.c
> b/drivers/gpu/drm/xe/xe_svm.c
> index ee150139470f..985ac20c5b07 100644
> --- a/drivers/gpu/drm/xe/xe_svm.c
> +++ b/drivers/gpu/drm/xe/xe_svm.c
> @@ -19,6 +19,11 @@ static struct xe_vm *range_to_vm(struct
> drm_gpusvm_range *r)
> return gpusvm_to_vm(r->gpusvm);
> }
>
> +static void *xe_svm_devm_owner(struct xe_device *xe)
> +{
> + return xe;
> +}
> +
> static struct drm_gpusvm_range *
> xe_svm_range_alloc(struct drm_gpusvm *gpusvm)
> {
> @@ -307,8 +312,8 @@ int xe_svm_init(struct xe_vm *vm)
> xe_svm_garbage_collector_work_func);
>
> err = drm_gpusvm_init(&vm->svm.gpusvm, "Xe SVM", &vm->xe-
> >drm,
> - current->mm, NULL, 0, vm->size,
> - SZ_512M, &gpusvm_ops,
> fault_chunk_sizes,
> + current->mm, xe_svm_devm_owner(vm-
> >xe), 0,
> + vm->size, SZ_512M, &gpusvm_ops,
> fault_chunk_sizes,
> ARRAY_SIZE(fault_chunk_sizes));
> if (err)
> return err;
> @@ -443,3 +448,56 @@ bool xe_svm_has_mapping(struct xe_vm *vm, u64
> start, u64 end)
> {
> return drm_gpusvm_has_mapping(&vm->svm.gpusvm, start, end);
> }
> +
> +#if IS_ENABLED(CONFIG_DRM_XE_DEVMEM_MIRROR)
> +/**
> + * xe_devm_add: Remap and provide memmap backing for device memory
> + * @tile: tile that the memory region belongs to
> + * @mr: memory region to remap
> + *
> + * This remap device memory to host physical address space and
> create
> + * struct page to back device memory
> + *
> + * Return: 0 on success standard error code otherwise
> + */
> +int xe_devm_add(struct xe_tile *tile, struct xe_mem_region *mr)
> +{
> + struct xe_device *xe = tile_to_xe(tile);
> + struct device *dev = &to_pci_dev(xe->drm.dev)->dev;
> + struct resource *res;
> + void *addr;
> + int ret;
> +
> + res = devm_request_free_mem_region(dev, &iomem_resource,
> + mr->usable_size);
> + if (IS_ERR(res)) {
> + ret = PTR_ERR(res);
> + return ret;
> + }
> +
> + mr->pagemap.type = MEMORY_DEVICE_PRIVATE;
> + mr->pagemap.range.start = res->start;
> + mr->pagemap.range.end = res->end;
> + mr->pagemap.nr_range = 1;
> + mr->pagemap.ops = drm_gpusvm_pagemap_ops_get();
> + mr->pagemap.owner = xe_svm_devm_owner(xe);
> + addr = devm_memremap_pages(dev, &mr->pagemap);
> + if (IS_ERR(addr)) {
> + devm_release_mem_region(dev, res->start,
> resource_size(res));
> + ret = PTR_ERR(addr);
> + drm_err(&xe->drm, "Failed to remap tile %d memory,
> errno %pe\n",
> + tile->id, ERR_PTR(ret));
> + return ret;
> + }
> + mr->hpa_base = res->start;
> +
> + drm_info(&xe->drm, "Added tile %d memory [%llx-%llx] to
> devm, remapped to %pr\n",
> + tile->id, mr->io_start, mr->io_start + mr-
> >usable_size, res);
> + return 0;
> +}
> +#else
> +int xe_devm_add(struct xe_tile *tile, struct xe_mem_region *mr)
> +{
> + return 0;
> +}
> +#endif
> diff --git a/drivers/gpu/drm/xe/xe_svm.h
> b/drivers/gpu/drm/xe/xe_svm.h
> index b181c174ca61..63daffdfdbf6 100644
> --- a/drivers/gpu/drm/xe/xe_svm.h
> +++ b/drivers/gpu/drm/xe/xe_svm.h
> @@ -11,6 +11,7 @@
>
> #define XE_INTERCONNECT_VRAM DRM_INTERCONNECT_DRIVER
>
> +struct xe_mem_region;
> struct xe_tile;
> struct xe_vm;
> struct xe_vma;
> @@ -36,6 +37,8 @@ struct xe_svm_range {
> u8 tile_invalidated;
> };
>
> +int xe_devm_add(struct xe_tile *tile, struct xe_mem_region *mr);
> +
> int xe_svm_init(struct xe_vm *vm);
>
> void xe_svm_fini(struct xe_vm *vm);
> diff --git a/drivers/gpu/drm/xe/xe_tile.c
> b/drivers/gpu/drm/xe/xe_tile.c
> index 2825553b568f..6c80a637ded5 100644
> --- a/drivers/gpu/drm/xe/xe_tile.c
> +++ b/drivers/gpu/drm/xe/xe_tile.c
> @@ -13,6 +13,7 @@
> #include "xe_migrate.h"
> #include "xe_pcode.h"
> #include "xe_sa.h"
> +#include "xe_svm.h"
> #include "xe_tile.h"
> #include "xe_tile_sysfs.h"
> #include "xe_ttm_vram_mgr.h"
> @@ -164,6 +165,7 @@ 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);
> @@ -172,6 +174,9 @@ int xe_tile_init_noalloc(struct xe_tile *tile)
>
> xe_wa_apply_tile_workarounds(tile);
>
> + if (xe->info.has_usm && IS_DGFX(xe))
> + xe_devm_add(tile, &tile->mem.vram);
> +
> err = xe_tile_sysfs_init(tile);
>
> return 0;
