From: Matthew Brost <matthew.brost@intel.com>
To: intel-xe@lists.freedesktop.org
Cc: stuart.summers@intel.com, arvind.yadav@intel.com,
himal.prasad.ghimiray@intel.com,
thomas.hellstrom@linux.intel.com, francois.dugast@intel.com
Subject: [PATCH v2 02/12] drm/xe: Allow prefetch-only VM bind IOCTLs to use VM read lock
Date: Wed, 25 Feb 2026 10:47:03 -0800 [thread overview]
Message-ID: <20260225184713.2606772-3-matthew.brost@intel.com> (raw)
In-Reply-To: <20260225184713.2606772-1-matthew.brost@intel.com>
Prefetch-only VM bind IOCTLs do not modify VMAs after pinning userptr
pages. Downgrade vm->lock to read mode once pinning is complete.
Lays the groundwork for prefetch IOCTLs to use threaded migration.
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
---
drivers/gpu/drm/xe/xe_vm.c | 36 +++++++++++++++++++++++++++-----
drivers/gpu/drm/xe/xe_vm_types.h | 2 ++
2 files changed, 33 insertions(+), 5 deletions(-)
diff --git a/drivers/gpu/drm/xe/xe_vm.c b/drivers/gpu/drm/xe/xe_vm.c
index 3332a86f464f..204a89ca3397 100644
--- a/drivers/gpu/drm/xe/xe_vm.c
+++ b/drivers/gpu/drm/xe/xe_vm.c
@@ -2336,10 +2336,12 @@ vm_bind_ioctl_ops_create(struct xe_vm *vm, struct xe_vma_ops *vops,
.map.gem.offset = bo_offset_or_userptr,
};
+ vops->flags |= XE_VMA_OPS_FLAG_MODIFIES_GPUVA;
ops = drm_gpuvm_sm_map_ops_create(&vm->gpuvm, &map_req);
break;
}
case DRM_XE_VM_BIND_OP_UNMAP:
+ vops->flags |= XE_VMA_OPS_FLAG_MODIFIES_GPUVA;
ops = drm_gpuvm_sm_unmap_ops_create(&vm->gpuvm, addr, range);
break;
case DRM_XE_VM_BIND_OP_PREFETCH:
@@ -2348,6 +2350,7 @@ vm_bind_ioctl_ops_create(struct xe_vm *vm, struct xe_vma_ops *vops,
case DRM_XE_VM_BIND_OP_UNMAP_ALL:
xe_assert(vm->xe, bo);
+ vops->flags |= XE_VMA_OPS_FLAG_MODIFIES_GPUVA;
err = xe_bo_lock(bo, true);
if (err)
return ERR_PTR(err);
@@ -2397,6 +2400,9 @@ vm_bind_ioctl_ops_create(struct xe_vm *vm, struct xe_vma_ops *vops,
u8 id, tile_mask = 0;
u32 i;
+ if (xe_vma_is_userptr(vma))
+ vops->flags |= XE_VMA_OPS_FLAG_MODIFIES_GPUVA;
+
if (!xe_vma_is_cpu_addr_mirror(vma)) {
op->prefetch.region = prefetch_region;
break;
@@ -2582,10 +2588,12 @@ static int xe_vma_op_commit(struct xe_vm *vm, struct xe_vma_op *op)
{
int err = 0;
- xe_vm_assert_write_mode_or_garbage_collector(vm);
+ lockdep_assert_held(&vm->lock);
switch (op->base.op) {
case DRM_GPUVA_OP_MAP:
+ xe_vm_assert_write_mode_or_garbage_collector(vm);
+
err |= xe_vm_insert_vma(vm, op->map.vma);
if (!err)
op->flags |= XE_VMA_OP_COMMITTED;
@@ -2595,6 +2603,8 @@ static int xe_vma_op_commit(struct xe_vm *vm, struct xe_vma_op *op)
u8 tile_present =
gpuva_to_vma(op->base.remap.unmap->va)->tile_present;
+ xe_vm_assert_write_mode_or_garbage_collector(vm);
+
prep_vma_destroy(vm, gpuva_to_vma(op->base.remap.unmap->va),
true);
op->flags |= XE_VMA_OP_COMMITTED;
@@ -2628,6 +2638,8 @@ static int xe_vma_op_commit(struct xe_vm *vm, struct xe_vma_op *op)
break;
}
case DRM_GPUVA_OP_UNMAP:
+ xe_vm_assert_write_mode_or_garbage_collector(vm);
+
prep_vma_destroy(vm, gpuva_to_vma(op->base.unmap.va), true);
op->flags |= XE_VMA_OP_COMMITTED;
break;
@@ -2849,10 +2861,12 @@ static void xe_vma_op_unwind(struct xe_vm *vm, struct xe_vma_op *op,
bool post_commit, bool prev_post_commit,
bool next_post_commit)
{
- xe_vm_assert_write_mode_or_garbage_collector(vm);
+ lockdep_assert_held(&vm->lock);
switch (op->base.op) {
case DRM_GPUVA_OP_MAP:
+ xe_vm_assert_write_mode_or_garbage_collector(vm);
+
if (op->map.vma) {
prep_vma_destroy(vm, op->map.vma, post_commit);
xe_vma_destroy_unlocked(op->map.vma);
@@ -2862,6 +2876,8 @@ static void xe_vma_op_unwind(struct xe_vm *vm, struct xe_vma_op *op,
{
struct xe_vma *vma = gpuva_to_vma(op->base.unmap.va);
+ xe_vm_assert_write_mode_or_garbage_collector(vm);
+
if (vma) {
xe_svm_notifier_lock(vm);
vma->gpuva.flags &= ~XE_VMA_DESTROYED;
@@ -2875,6 +2891,8 @@ static void xe_vma_op_unwind(struct xe_vm *vm, struct xe_vma_op *op,
{
struct xe_vma *vma = gpuva_to_vma(op->base.remap.unmap->va);
+ xe_vm_assert_write_mode_or_garbage_collector(vm);
+
if (op->remap.prev) {
prep_vma_destroy(vm, op->remap.prev, prev_post_commit);
xe_vma_destroy_unlocked(op->remap.prev);
@@ -3362,7 +3380,7 @@ static struct dma_fence *vm_bind_ioctl_ops_execute(struct xe_vm *vm,
struct dma_fence *fence;
int err = 0;
- lockdep_assert_held_write(&vm->lock);
+ lockdep_assert_held(&vm->lock);
xe_validation_guard(&ctx, &vm->xe->val, &exec,
((struct xe_val_flags) {
@@ -3664,7 +3682,7 @@ int xe_vm_bind_ioctl(struct drm_device *dev, void *data, struct drm_file *file)
u32 num_syncs, num_ufence = 0;
struct xe_sync_entry *syncs = NULL;
struct drm_xe_vm_bind_op *bind_ops = NULL;
- struct xe_vma_ops vops;
+ struct xe_vma_ops vops = { .flags = 0, };
struct dma_fence *fence;
int err;
int i;
@@ -3839,6 +3857,11 @@ int xe_vm_bind_ioctl(struct drm_device *dev, void *data, struct drm_file *file)
goto unwind_ops;
}
+ if (!(vops.flags & XE_VMA_OPS_FLAG_MODIFIES_GPUVA)) {
+ vops.flags |= XE_VMA_OPS_FLAG_DOWNGRADE_LOCK;
+ downgrade_write(&vm->lock);
+ }
+
err = xe_vma_ops_alloc(&vops, args->num_binds > 1);
if (err)
goto unwind_ops;
@@ -3875,7 +3898,10 @@ int xe_vm_bind_ioctl(struct drm_device *dev, void *data, struct drm_file *file)
free_bos:
kvfree(bos);
release_vm_lock:
- up_write(&vm->lock);
+ if (vops.flags & XE_VMA_OPS_FLAG_DOWNGRADE_LOCK)
+ up_read(&vm->lock);
+ else
+ up_write(&vm->lock);
put_exec_queue:
if (q)
xe_exec_queue_put(q);
diff --git a/drivers/gpu/drm/xe/xe_vm_types.h b/drivers/gpu/drm/xe/xe_vm_types.h
index 9c91934ec47f..db6e8e22a69f 100644
--- a/drivers/gpu/drm/xe/xe_vm_types.h
+++ b/drivers/gpu/drm/xe/xe_vm_types.h
@@ -518,6 +518,8 @@ struct xe_vma_ops {
#define XE_VMA_OPS_ARRAY_OF_BINDS BIT(2)
#define XE_VMA_OPS_FLAG_SKIP_TLB_WAIT BIT(3)
#define XE_VMA_OPS_FLAG_ALLOW_SVM_UNMAP BIT(4)
+#define XE_VMA_OPS_FLAG_MODIFIES_GPUVA BIT(5)
+#define XE_VMA_OPS_FLAG_DOWNGRADE_LOCK BIT(6)
u32 flags;
#ifdef TEST_VM_OPS_ERROR
/** @inject_error: inject error to test error handling */
--
2.34.1
next prev parent reply other threads:[~2026-02-25 18:47 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-02-25 18:47 [PATCH v2 00/12] Fine grained fault locking, threaded prefetch, storm cache Matthew Brost
2026-02-25 18:47 ` [PATCH v2 01/12] drm/xe: Fine grained page fault locking Matthew Brost
2026-02-25 18:47 ` Matthew Brost [this message]
2026-02-25 18:47 ` [PATCH v2 03/12] drm/xe: Thread prefetch of SVM ranges Matthew Brost
2026-02-25 18:47 ` [PATCH v2 04/12] drm/xe: Use a single page-fault queue with multiple workers Matthew Brost
2026-02-25 18:47 ` [PATCH v2 05/12] drm/xe: Add num_pf_work modparam Matthew Brost
2026-02-25 18:47 ` [PATCH v2 06/12] drm/xe: Engine class and instance into a u8 Matthew Brost
2026-02-25 18:47 ` [PATCH v2 07/12] drm/xe: Track pagefault worker runtime Matthew Brost
2026-02-25 18:47 ` [PATCH v2 08/12] drm/xe: Chain page faults via queue-resident cache to avoid fault storms Matthew Brost
2026-02-25 18:47 ` [PATCH v2 09/12] drm/xe: Add pagefault chaining stats Matthew Brost
2026-02-25 18:47 ` [PATCH v2 10/12] drm/xe: Add debugfs pagefault_info Matthew Brost
2026-02-25 18:47 ` [PATCH v2 11/12] drm/xe: batch CT pagefault acks with periodic flush Matthew Brost
2026-02-25 18:47 ` [PATCH v2 12/12] drm/xe: Track parallel page fault activity in GT stats Matthew Brost
2026-02-25 19:45 ` ✗ CI.checkpatch: warning for Fine grained fault locking, threaded prefetch, storm cache Patchwork
2026-02-25 19:45 ` ✗ CI.KUnit: failure " Patchwork
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