[PATCH v4 18/20] drm/xe/bo: Update atomic_access attribute on madvise
Himal Prasad Ghimiray
himal.prasad.ghimiray at intel.com
Fri Jun 13 12:55:56 UTC 2025
Update the bo_atomic_access based on user-provided input and determine
the migration to smem during a CPU fault
v2 (Matthew Brost)
- Avoid cpu unmapping if bo is already in smem
- check atomics on smem too for ioctl
- Add comments
v3
- Avoid migration in prefetch
Cc: Matthew Brost <matthew.brost at intel.com>
Signed-off-by: Himal Prasad Ghimiray <himal.prasad.ghimiray at intel.com>
---
drivers/gpu/drm/xe/xe_bo.c | 21 ++++++++--
drivers/gpu/drm/xe/xe_gt_pagefault.c | 2 +-
drivers/gpu/drm/xe/xe_vm.c | 5 ++-
drivers/gpu/drm/xe/xe_vm_madvise.c | 61 +++++++++++++++++++++++++++-
4 files changed, 82 insertions(+), 7 deletions(-)
diff --git a/drivers/gpu/drm/xe/xe_bo.c b/drivers/gpu/drm/xe/xe_bo.c
index 4e39188a021a..82b33dfc5515 100644
--- a/drivers/gpu/drm/xe/xe_bo.c
+++ b/drivers/gpu/drm/xe/xe_bo.c
@@ -1667,6 +1667,12 @@ static void xe_gem_object_close(struct drm_gem_object *obj,
}
}
+static bool should_migrate_to_smem(struct xe_bo *bo)
+{
+ return bo->attr.atomic_access == DRM_XE_VMA_ATOMIC_GLOBAL ||
+ bo->attr.atomic_access == DRM_XE_VMA_ATOMIC_CPU;
+}
+
static vm_fault_t xe_gem_fault(struct vm_fault *vmf)
{
struct ttm_buffer_object *tbo = vmf->vma->vm_private_data;
@@ -1675,7 +1681,7 @@ static vm_fault_t xe_gem_fault(struct vm_fault *vmf)
struct xe_bo *bo = ttm_to_xe_bo(tbo);
bool needs_rpm = bo->flags & XE_BO_FLAG_VRAM_MASK;
vm_fault_t ret;
- int idx;
+ int idx, r = 0;
if (needs_rpm)
xe_pm_runtime_get(xe);
@@ -1687,8 +1693,17 @@ static vm_fault_t xe_gem_fault(struct vm_fault *vmf)
if (drm_dev_enter(ddev, &idx)) {
trace_xe_bo_cpu_fault(bo);
- ret = ttm_bo_vm_fault_reserved(vmf, vmf->vma->vm_page_prot,
- TTM_BO_VM_NUM_PREFAULT);
+ if (should_migrate_to_smem(bo)) {
+ r = xe_bo_migrate(bo, XE_PL_TT);
+ if (r == -EBUSY || r == -ERESTARTSYS || r == -EINTR)
+ ret = VM_FAULT_NOPAGE;
+ else if (r)
+ ret = VM_FAULT_SIGBUS;
+ }
+ if (!ret)
+ ret = ttm_bo_vm_fault_reserved(vmf,
+ vmf->vma->vm_page_prot,
+ TTM_BO_VM_NUM_PREFAULT);
drm_dev_exit(idx);
} else {
ret = ttm_bo_vm_dummy_page(vmf, vmf->vma->vm_page_prot);
diff --git a/drivers/gpu/drm/xe/xe_gt_pagefault.c b/drivers/gpu/drm/xe/xe_gt_pagefault.c
index e2d975b2fddb..1335c5fc0e10 100644
--- a/drivers/gpu/drm/xe/xe_gt_pagefault.c
+++ b/drivers/gpu/drm/xe/xe_gt_pagefault.c
@@ -89,7 +89,7 @@ static int xe_pf_begin(struct drm_exec *exec, struct xe_vma *vma,
if (err)
return err;
- if (atomic && IS_DGFX(vm->xe)) {
+ if (xe_vma_need_vram_for_atomic(vm->xe, vma, atomic)) {
if (xe_vma_is_userptr(vma)) {
err = -EACCES;
return err;
diff --git a/drivers/gpu/drm/xe/xe_vm.c b/drivers/gpu/drm/xe/xe_vm.c
index 0dd9f9e11030..14e554f3f4d5 100644
--- a/drivers/gpu/drm/xe/xe_vm.c
+++ b/drivers/gpu/drm/xe/xe_vm.c
@@ -4200,6 +4200,9 @@ void xe_vm_snapshot_free(struct xe_vm_snapshot *snap)
*/
bool xe_vma_need_vram_for_atomic(struct xe_device *xe, struct xe_vma *vma, bool is_atomic)
{
+ u32 atomic_access = xe_vma_bo(vma) ? xe_vma_bo(vma)->attr.atomic_access :
+ vma->attr.atomic_access;
+
if (!IS_DGFX(xe))
return false;
@@ -4207,7 +4210,7 @@ bool xe_vma_need_vram_for_atomic(struct xe_device *xe, struct xe_vma *vma, bool
* on a device supporting CXL atomics, these would ideally work universally
* without additional handling.
*/
- switch (vma->attr.atomic_access) {
+ switch (atomic_access) {
case DRM_XE_VMA_ATOMIC_DEVICE:
return !xe->info.has_device_atomics_on_smem;
diff --git a/drivers/gpu/drm/xe/xe_vm_madvise.c b/drivers/gpu/drm/xe/xe_vm_madvise.c
index 973627edb23c..5b96c8fc73a5 100644
--- a/drivers/gpu/drm/xe/xe_vm_madvise.c
+++ b/drivers/gpu/drm/xe/xe_vm_madvise.c
@@ -102,14 +102,28 @@ static void madvise_atomic(struct xe_device *xe, struct xe_vm *vm,
struct xe_vma **vmas, int num_vmas,
struct drm_xe_madvise *op)
{
+ struct xe_bo *bo;
int i;
xe_assert(vm->xe, op->type == DRM_XE_VMA_ATTR_ATOMIC);
xe_assert(vm->xe, op->atomic.val <= DRM_XE_VMA_ATOMIC_CPU);
- for (i = 0; i < num_vmas; i++)
+ for (i = 0; i < num_vmas; i++) {
vmas[i]->attr.atomic_access = op->atomic.val;
- /*TODO: handle bo backed vmas */
+
+ bo = xe_vma_bo(vmas[i]);
+ if (!bo)
+ continue;
+
+ xe_bo_assert_held(bo);
+ bo->attr.atomic_access = op->atomic.val;
+
+ /* Invalidate cpu page table, so bo can migrate to smem in next access */
+ if (xe_bo_is_vram(bo) &&
+ (bo->attr.atomic_access == DRM_XE_VMA_ATOMIC_CPU ||
+ bo->attr.atomic_access == DRM_XE_VMA_ATOMIC_GLOBAL))
+ ttm_bo_unmap_virtual(&bo->ttm);
+ }
}
static void madvise_pat_index(struct xe_device *xe, struct xe_vm *vm,
@@ -231,6 +245,41 @@ static int drm_xe_madvise_args_are_sane(struct xe_device *xe, const struct drm_x
return 0;
}
+static int check_bo_args_are_sane(struct xe_vm *vm, struct xe_vma **vmas,
+ int num_vmas, u32 atomic_val)
+{
+ struct xe_device *xe = vm->xe;
+ struct xe_bo *bo;
+ int i;
+
+ for (i = 0; i < num_vmas; i++) {
+ bo = xe_vma_bo(vmas[i]);
+ if (!bo)
+ continue;
+
+ if (XE_IOCTL_DBG(xe, atomic_val == DRM_XE_VMA_ATOMIC_CPU &&
+ !(bo->flags & XE_BO_FLAG_SYSTEM)))
+ return -EINVAL;
+
+ /* NOTE: The following atomic checks are platform-specific. For example,
+ * if a device supports CXL atomics, these may not be necessary or
+ * may behave differently.
+ */
+ if (XE_IOCTL_DBG(xe, atomic_val == DRM_XE_VMA_ATOMIC_DEVICE &&
+ !(bo->flags & XE_BO_FLAG_VRAM0) &&
+ !(bo->flags & XE_BO_FLAG_VRAM1) &&
+ !(bo->flags & XE_BO_FLAG_SYSTEM &&
+ xe->info.has_device_atomics_on_smem)))
+ return -EINVAL;
+
+ if (XE_IOCTL_DBG(xe, atomic_val == DRM_XE_VMA_ATOMIC_GLOBAL &&
+ (!(bo->flags & XE_BO_FLAG_SYSTEM) ||
+ (!(bo->flags & XE_BO_FLAG_VRAM0) &&
+ !(bo->flags & XE_BO_FLAG_VRAM1)))))
+ return -EINVAL;
+ }
+ return 0;
+}
/**
* xe_vm_madvise_ioctl - Handle MADVise ioctl for a VM
* @dev: DRM device pointer
@@ -276,6 +325,14 @@ int xe_vm_madvise_ioctl(struct drm_device *dev, void *data, struct drm_file *fil
goto unlock_vm;
if (madvise_range.has_bo_vmas) {
+ if (args->type == DRM_XE_VMA_ATTR_ATOMIC) {
+ err = check_bo_args_are_sane(vm, madvise_range.vmas,
+ madvise_range.num_vmas,
+ args->atomic.val);
+ if (err)
+ goto unlock_vm;
+ }
+
drm_exec_init(&exec, DRM_EXEC_IGNORE_DUPLICATES, 0);
drm_exec_until_all_locked(&exec) {
for (int i = 0; i < madvise_range.num_vmas; i++) {
--
2.34.1
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