[PATCH] drm/xe: Replace the scratch pages with NULL PTEs
Thomas Hellström
thomas.hellstrom at linux.intel.com
Thu Dec 7 15:44:23 UTC 2023
Replace the scratch pages with NULL PTEs that return 0 when reading and
do nothing when writing.
Cc: Brian Welty <brian.welty at intel.com>
Signed-off-by: Thomas Hellström <thomas.hellstrom at linux.intel.com>
---
drivers/gpu/drm/xe/xe_pt.c | 68 ++++----------------------------
drivers/gpu/drm/xe/xe_pt.h | 3 --
drivers/gpu/drm/xe/xe_vm.c | 45 +--------------------
drivers/gpu/drm/xe/xe_vm.h | 5 +++
drivers/gpu/drm/xe/xe_vm_types.h | 2 -
5 files changed, 14 insertions(+), 109 deletions(-)
diff --git a/drivers/gpu/drm/xe/xe_pt.c b/drivers/gpu/drm/xe/xe_pt.c
index 35bd7940a571..ce2846d56b04 100644
--- a/drivers/gpu/drm/xe/xe_pt.c
+++ b/drivers/gpu/drm/xe/xe_pt.c
@@ -50,17 +50,14 @@ static struct xe_pt *xe_pt_entry(struct xe_pt_dir *pt_dir, unsigned int index)
static u64 __xe_pt_empty_pte(struct xe_tile *tile, struct xe_vm *vm,
unsigned int level)
{
- u16 pat_index = tile_to_xe(tile)->pat.idx[XE_CACHE_WB];
- u8 id = tile->id;
+ struct xe_device *xe = tile_to_xe(tile);
+ u16 pat_index = xe->pat.idx[XE_CACHE_WB];
- if (!vm->scratch_bo[id])
+ if (!xe_vm_has_scratch(vm))
return 0;
- if (level > 0)
- return vm->pt_ops->pde_encode_bo(vm->scratch_pt[id][level - 1]->bo,
- 0, pat_index);
-
- return vm->pt_ops->pte_encode_bo(vm->scratch_bo[id], 0, pat_index, 0);
+ return vm->pt_ops->pte_encode_addr(xe, 0, pat_index, level, IS_DGFX(xe),
+ 0) | XE_PTE_NULL;
}
/**
@@ -135,7 +132,7 @@ void xe_pt_populate_empty(struct xe_tile *tile, struct xe_vm *vm,
u64 empty;
int i;
- if (!vm->scratch_bo[tile->id]) {
+ if (!xe_vm_has_scratch(vm)) {
/*
* FIXME: Some memory is allocated already allocated to zero?
* Find out which memory that is and avoid this memset...
@@ -194,57 +191,6 @@ void xe_pt_destroy(struct xe_pt *pt, u32 flags, struct llist_head *deferred)
kfree(pt);
}
-/**
- * xe_pt_create_scratch() - Setup a scratch memory pagetable tree for the
- * given tile and vm.
- * @xe: xe device.
- * @tile: tile to set up for.
- * @vm: vm to set up for.
- *
- * Sets up a pagetable tree with one page-table per level and a single
- * leaf bo. All pagetable entries point to the single page-table or,
- * for L0, the single bo one level below.
- *
- * Return: 0 on success, negative error code on error.
- */
-int xe_pt_create_scratch(struct xe_device *xe, struct xe_tile *tile,
- struct xe_vm *vm)
-{
- u8 id = tile->id;
- unsigned int flags;
- int i;
-
- /*
- * So we don't need to worry about 64K TLB hints when dealing with
- * scratch entires, rather keep the scratch page in system memory on
- * platforms where 64K pages are needed for VRAM.
- */
- flags = XE_BO_CREATE_PINNED_BIT;
- if (vm->flags & XE_VM_FLAG_64K)
- flags |= XE_BO_CREATE_SYSTEM_BIT;
- else
- flags |= XE_BO_CREATE_VRAM_IF_DGFX(tile);
-
- vm->scratch_bo[id] = xe_bo_create_pin_map(xe, tile, vm, SZ_4K,
- ttm_bo_type_kernel,
- flags);
- if (IS_ERR(vm->scratch_bo[id]))
- return PTR_ERR(vm->scratch_bo[id]);
-
- xe_map_memset(vm->xe, &vm->scratch_bo[id]->vmap, 0, 0,
- vm->scratch_bo[id]->size);
-
- for (i = 0; i < vm->pt_root[id]->level; i++) {
- vm->scratch_pt[id][i] = xe_pt_create(vm, tile, i);
- if (IS_ERR(vm->scratch_pt[id][i]))
- return PTR_ERR(vm->scratch_pt[id][i]);
-
- xe_pt_populate_empty(tile, vm, vm->scratch_pt[id][i]);
- }
-
- return 0;
-}
-
/**
* DOC: Pagetable building
*
@@ -1286,7 +1232,7 @@ __xe_pt_bind_vma(struct xe_tile *tile, struct xe_vma *vma, struct xe_exec_queue
* it needs to be done here.
*/
if ((rebind && !xe_vm_in_lr_mode(vm) && !vm->batch_invalidate_tlb) ||
- (!rebind && vm->scratch_bo[tile->id] && xe_vm_in_preempt_fence_mode(vm))) {
+ (!rebind && xe_vm_has_scratch(vm) && xe_vm_in_preempt_fence_mode(vm))) {
ifence = kzalloc(sizeof(*ifence), GFP_KERNEL);
if (!ifence)
return ERR_PTR(-ENOMEM);
diff --git a/drivers/gpu/drm/xe/xe_pt.h b/drivers/gpu/drm/xe/xe_pt.h
index d5460e58dbbf..6f7359ac55bd 100644
--- a/drivers/gpu/drm/xe/xe_pt.h
+++ b/drivers/gpu/drm/xe/xe_pt.h
@@ -26,9 +26,6 @@ unsigned int xe_pt_shift(unsigned int level);
struct xe_pt *xe_pt_create(struct xe_vm *vm, struct xe_tile *tile,
unsigned int level);
-int xe_pt_create_scratch(struct xe_device *xe, struct xe_tile *tile,
- struct xe_vm *vm);
-
void xe_pt_populate_empty(struct xe_tile *tile, struct xe_vm *vm,
struct xe_pt *pt);
diff --git a/drivers/gpu/drm/xe/xe_vm.c b/drivers/gpu/drm/xe/xe_vm.c
index e09050f16f07..868b9a2a5d02 100644
--- a/drivers/gpu/drm/xe/xe_vm.c
+++ b/drivers/gpu/drm/xe/xe_vm.c
@@ -1332,7 +1332,7 @@ static void vm_destroy_work_func(struct work_struct *w);
struct xe_vm *xe_vm_create(struct xe_device *xe, u32 flags)
{
struct xe_vm *vm;
- int err, i = 0, number_tiles = 0;
+ int err, number_tiles = 0;
struct xe_tile *tile;
u8 id;
@@ -1397,17 +1397,8 @@ struct xe_vm *xe_vm_create(struct xe_device *xe, u32 flags)
}
}
- if (flags & XE_VM_FLAG_SCRATCH_PAGE) {
- for_each_tile(tile, xe, id) {
- if (!vm->pt_root[id])
- continue;
-
- err = xe_pt_create_scratch(xe, tile, vm);
- if (err)
- goto err_scratch_pt;
- }
+ if (xe_vm_has_scratch(vm))
vm->batch_invalidate_tlb = true;
- }
if (flags & XE_VM_FLAG_LR_MODE) {
INIT_WORK(&vm->preempt.rebind_work, preempt_rebind_work_func);
@@ -1415,7 +1406,6 @@ struct xe_vm *xe_vm_create(struct xe_device *xe, u32 flags)
vm->batch_invalidate_tlb = false;
}
- /* Fill pt_root after allocating scratch tables */
for_each_tile(tile, xe, id) {
if (!vm->pt_root[id])
continue;
@@ -1465,19 +1455,6 @@ struct xe_vm *xe_vm_create(struct xe_device *xe, u32 flags)
return vm;
-err_scratch_pt:
- for_each_tile(tile, xe, id) {
- if (!vm->pt_root[id])
- continue;
-
- i = vm->pt_root[id]->level;
- while (i)
- if (vm->scratch_pt[id][--i])
- xe_pt_destroy(vm->scratch_pt[id][i],
- vm->flags, NULL);
- xe_bo_unpin(vm->scratch_bo[id]);
- xe_bo_put(vm->scratch_bo[id]);
- }
err_destroy_root:
for_each_tile(tile, xe, id) {
if (vm->pt_root[id])
@@ -1556,24 +1533,6 @@ void xe_vm_close_and_put(struct xe_vm *vm)
vma->gpuva.flags |= XE_VMA_DESTROYED;
}
- /*
- * All vm operations will add shared fences to resv.
- * The only exception is eviction for a shared object,
- * but even so, the unbind when evicted would still
- * install a fence to resv. Hence it's safe to
- * destroy the pagetables immediately.
- */
- for_each_tile(tile, xe, id) {
- if (vm->scratch_bo[id]) {
- u32 i;
-
- xe_bo_unpin(vm->scratch_bo[id]);
- xe_bo_put(vm->scratch_bo[id]);
- for (i = 0; i < vm->pt_root[id]->level; i++)
- xe_pt_destroy(vm->scratch_pt[id][i], vm->flags,
- NULL);
- }
- }
xe_vm_unlock(vm);
/*
diff --git a/drivers/gpu/drm/xe/xe_vm.h b/drivers/gpu/drm/xe/xe_vm.h
index 9a0ae19c47b7..b92d8f54011d 100644
--- a/drivers/gpu/drm/xe/xe_vm.h
+++ b/drivers/gpu/drm/xe/xe_vm.h
@@ -61,6 +61,11 @@ static inline bool xe_vm_is_closed_or_banned(struct xe_vm *vm)
return xe_vm_is_closed(vm) || xe_vm_is_banned(vm);
}
+static inline bool xe_vm_has_scratch(const struct xe_vm *vm)
+{
+ return vm->flags & XE_VM_FLAG_SCRATCH_PAGE;
+}
+
struct xe_vma *
xe_vm_find_overlapping_vma(struct xe_vm *vm, u64 start, u64 range);
diff --git a/drivers/gpu/drm/xe/xe_vm_types.h b/drivers/gpu/drm/xe/xe_vm_types.h
index 23abdfd8622f..a5762e99e6aa 100644
--- a/drivers/gpu/drm/xe/xe_vm_types.h
+++ b/drivers/gpu/drm/xe/xe_vm_types.h
@@ -158,8 +158,6 @@ struct xe_vm {
u64 size;
struct xe_pt *pt_root[XE_MAX_TILES_PER_DEVICE];
- struct xe_bo *scratch_bo[XE_MAX_TILES_PER_DEVICE];
- struct xe_pt *scratch_pt[XE_MAX_TILES_PER_DEVICE][XE_VM_MAX_LEVEL];
/**
* @flags: flags for this VM, statically setup a creation time aside
--
2.42.0
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