Commit 6ca463ef authored by Himal Prasad Ghimiray's avatar Himal Prasad Ghimiray
Browse files

drm/xe/svm: Add xe_svm_ranges_zap_ptes_in_range() for PTE zapping 



Introduce xe_svm_ranges_zap_ptes_in_range(), a function to zap page table
entries (PTEs) for all SVM ranges within a user-specified address range.

-v2 (Matthew Brost)
Lock should be called even for tlb_invalidation

v3(Matthew Brost)
- Update comment
- s/notifier->itree.start/drm_gpusvm_notifier_start
- s/notifier->itree.last + 1/drm_gpusvm_notifier_end
- use WRITE_ONCE

Cc: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: default avatarMatthew Brost <matthew.brost@intel.com>
Link: https://lore.kernel.org/r/20250821173104.3030148-8-himal.prasad.ghimiray@intel.com


Signed-off-by: default avatarHimal Prasad Ghimiray <himal.prasad.ghimiray@intel.com>
parent 6ad887f3

drivers/gpu/drm/xe/xe_pt.c

+13 −1
Original line number Diff line number Diff line
@@ -950,7 +950,19 @@ bool xe_pt_zap_ptes_range(struct xe_tile *tile, struct xe_vm *vm, 
	struct xe_pt *pt = vm->pt_root[tile->id];

	u8 pt_mask = (range->tile_present & ~range->tile_invalidated);



	xe_svm_assert_in_notifier(vm);

	/*

	 * Locking rules:

	 *

	 * - notifier_lock (write): full protection against page table changes

	 *   and MMU notifier invalidations.

	 *

	 * - notifier_lock (read) + vm_lock (write): combined protection against

	 *   invalidations and concurrent page table modifications. (e.g., madvise)

	 *

	 */

	lockdep_assert(lockdep_is_held_type(&vm->svm.gpusvm.notifier_lock, 0) ||

		       (lockdep_is_held_type(&vm->svm.gpusvm.notifier_lock, 1) &&

		       lockdep_is_held_type(&vm->lock, 0)));



	if (!(pt_mask & BIT(tile->id)))

		return false;

drivers/gpu/drm/xe/xe_svm.c

+50 −0
Original line number Diff line number Diff line
@@ -1031,6 +1031,56 @@ int xe_svm_range_get_pages(struct xe_vm *vm, struct xe_svm_range *range, 
	return err;

}



/**

 * xe_svm_ranges_zap_ptes_in_range - clear ptes of svm ranges in input range

 * @vm: Pointer to the xe_vm structure

 * @start: Start of the input range

 * @end: End of the input range

 *

 * This function removes the page table entries (PTEs) associated

 * with the svm ranges within the given input start and end

 *

 * Return: tile_mask for which gt's need to be tlb invalidated.

 */

u8 xe_svm_ranges_zap_ptes_in_range(struct xe_vm *vm, u64 start, u64 end)

{

	struct drm_gpusvm_notifier *notifier;

	struct xe_svm_range *range;

	u64 adj_start, adj_end;

	struct xe_tile *tile;

	u8 tile_mask = 0;

	u8 id;



	lockdep_assert(lockdep_is_held_type(&vm->svm.gpusvm.notifier_lock, 1) &&

		       lockdep_is_held_type(&vm->lock, 0));



	drm_gpusvm_for_each_notifier(notifier, &vm->svm.gpusvm, start, end) {

		struct drm_gpusvm_range *r = NULL;



		adj_start = max(start, drm_gpusvm_notifier_start(notifier));

		adj_end = min(end, drm_gpusvm_notifier_end(notifier));

		drm_gpusvm_for_each_range(r, notifier, adj_start, adj_end) {

			range = to_xe_range(r);

			for_each_tile(tile, vm->xe, id) {

				if (xe_pt_zap_ptes_range(tile, vm, range)) {

					tile_mask |= BIT(id);

					/*

					 * WRITE_ONCE pairs with READ_ONCE in

					 * xe_vm_has_valid_gpu_mapping().

					 * Must not fail after setting

					 * tile_invalidated and before

					 * TLB invalidation.

					 */

					WRITE_ONCE(range->tile_invalidated,

						   range->tile_invalidated | BIT(id));

				}

			}

		}

	}



	return tile_mask;

}



#if IS_ENABLED(CONFIG_DRM_XE_PAGEMAP)



static struct drm_pagemap *tile_local_pagemap(struct xe_tile *tile)

drivers/gpu/drm/xe/xe_svm.h

+8 −0
Original line number Diff line number Diff line
@@ -92,6 +92,8 @@ u64 xe_svm_find_vma_start(struct xe_vm *vm, u64 addr, u64 end, struct xe_vma *v 


void xe_svm_unmap_address_range(struct xe_vm *vm, u64 start, u64 end);



u8 xe_svm_ranges_zap_ptes_in_range(struct xe_vm *vm, u64 start, u64 end);



/**

 * xe_svm_range_has_dma_mapping() - SVM range has DMA mapping

 * @range: SVM range
@@ -310,6 +312,12 @@ void xe_svm_unmap_address_range(struct xe_vm *vm, u64 start, u64 end) 
{

}



static inline

u8 xe_svm_ranges_zap_ptes_in_range(struct xe_vm *vm, u64 start, u64 end)

{

	return 0;

}



#define xe_svm_assert_in_notifier(...) do {} while (0)

#define xe_svm_range_has_dma_mapping(...) false