[PATCH v3] drm/xe/dgfx: Release mmap mappings on rpm suspend
Badal Nilawar
badal.nilawar at intel.com
Wed Dec 20 18:50:28 UTC 2023
Release all mmap mappings for all vram objects which are associated
with userfault such that, while pcie function in D3hot, any access
to memory mappings will raise a userfault.
Upon userfault, in order to access memory mappings, if graphics
function is in D3 then runtime resume of dgpu will be triggered to
transition to D0.
v2:
- Add lock dep assertion before updating vram_userfault_count (Rodrigo)
- Avoid iomem check before bo migration check as bo can migrate
to system memory (Matthew Auld)
v3:
- Delete bo userfault link during bo destroy
- Upon bo move (vram-smem), do bo userfault link deletion in
xe_bo_move_notify instead of xe_bo_move (Thomas Hellström)
- Grab lock in rpm hook while deleting bo userfault link (Matthew Auld)
Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
Cc: Matthew Auld <matthew.auld at intel.com>
Cc: Anshuman Gupta <anshuman.gupta at intel.com>
Signed-off-by: Badal Nilawar <badal.nilawar at intel.com>
---
drivers/gpu/drm/xe/xe_bo.c | 65 +++++++++++++++++++++++++++-
drivers/gpu/drm/xe/xe_bo.h | 2 +
drivers/gpu/drm/xe/xe_bo_types.h | 5 +++
drivers/gpu/drm/xe/xe_device_types.h | 20 +++++++++
drivers/gpu/drm/xe/xe_pm.c | 7 +++
5 files changed, 98 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/xe/xe_bo.c b/drivers/gpu/drm/xe/xe_bo.c
index 8e4a3b1f6b93..2ab933f50192 100644
--- a/drivers/gpu/drm/xe/xe_bo.c
+++ b/drivers/gpu/drm/xe/xe_bo.c
@@ -586,6 +586,8 @@ static int xe_bo_move_notify(struct xe_bo *bo,
{
struct ttm_buffer_object *ttm_bo = &bo->ttm;
struct xe_device *xe = ttm_to_xe_device(ttm_bo->bdev);
+ struct ttm_resource *old_mem = ttm_bo->resource;
+ u32 old_mem_type = old_mem ? old_mem->mem_type : XE_PL_SYSTEM;
int ret;
/*
@@ -597,6 +599,7 @@ static int xe_bo_move_notify(struct xe_bo *bo,
return -EINVAL;
xe_bo_vunmap(bo);
+
ret = xe_bo_trigger_rebind(xe, bo, ctx);
if (ret)
return ret;
@@ -605,6 +608,18 @@ static int xe_bo_move_notify(struct xe_bo *bo,
if (ttm_bo->base.dma_buf && !ttm_bo->base.import_attach)
dma_buf_move_notify(ttm_bo->base.dma_buf);
+ /*
+ * TTM has already nuked the mmap for us (see ttm_bo_unmap_virtual),
+ * so if we moved from VRAM make sure to unlink this from the userfault
+ * tracking.
+ */
+ if (mem_type_is_vram(old_mem_type)) {
+ spin_lock(&xe->mem_access.vram_userfault_lock);
+ if (!list_empty(&bo->vram_userfault_link))
+ list_del_init(&bo->vram_userfault_link);
+ spin_unlock(&xe->mem_access.vram_userfault_lock);
+ }
+
return 0;
}
@@ -1063,6 +1078,11 @@ static void xe_ttm_bo_destroy(struct ttm_buffer_object *ttm_bo)
if (bo->vm && xe_bo_is_user(bo))
xe_vm_put(bo->vm);
+ spin_lock(&xe->mem_access.vram_userfault_lock);
+ if (!list_empty(&bo->vram_userfault_link))
+ list_del(&bo->vram_userfault_link);
+ spin_unlock(&xe->mem_access.vram_userfault_lock);
+
kfree(bo);
}
@@ -1110,6 +1130,8 @@ static vm_fault_t xe_gem_fault(struct vm_fault *vmf)
{
struct ttm_buffer_object *tbo = vmf->vma->vm_private_data;
struct drm_device *ddev = tbo->base.dev;
+ struct xe_bo *bo = NULL;
+ struct xe_device *xe = to_xe_device(ddev);
vm_fault_t ret;
int idx, r = 0;
@@ -1118,7 +1140,7 @@ static vm_fault_t xe_gem_fault(struct vm_fault *vmf)
return ret;
if (drm_dev_enter(ddev, &idx)) {
- struct xe_bo *bo = ttm_to_xe_bo(tbo);
+ bo = ttm_to_xe_bo(tbo);
trace_xe_bo_cpu_fault(bo);
@@ -1137,10 +1159,31 @@ static vm_fault_t xe_gem_fault(struct vm_fault *vmf)
} else {
ret = ttm_bo_vm_dummy_page(vmf, vmf->vma->vm_page_prot);
}
+
if (ret == VM_FAULT_RETRY && !(vmf->flags & FAULT_FLAG_RETRY_NOWAIT))
return ret;
+ /*
+ * ttm_bo_vm_reserve() already has dma_resv_lock.
+ * vram_userfault_count is protected by dma_resv lock and rpm wakeref.
+ */
+ if (ret == VM_FAULT_NOPAGE && bo && !bo->vram_userfault_count) {
+ if (tbo->resource->bus.is_iomem) {
+ dma_resv_assert_held(tbo->base.resv);
+
+ xe_device_mem_access_get(xe);
+
+ bo->vram_userfault_count = 1;
+
+ spin_lock(&xe->mem_access.vram_userfault_lock);
+ list_add(&bo->vram_userfault_link, &xe->mem_access.vram_userfault_list);
+ spin_unlock(&xe->mem_access.vram_userfault_lock);
+
+ xe_device_mem_access_put(xe);
+ }
+ }
dma_resv_unlock(tbo->base.resv);
+
return ret;
}
@@ -1254,6 +1297,7 @@ struct xe_bo *___xe_bo_create_locked(struct xe_device *xe, struct xe_bo *bo,
#ifdef CONFIG_PROC_FS
INIT_LIST_HEAD(&bo->client_link);
#endif
+ INIT_LIST_HEAD(&bo->vram_userfault_link);
drm_gem_private_object_init(&xe->drm, &bo->ttm.base, size);
@@ -2264,6 +2308,25 @@ int xe_bo_dumb_create(struct drm_file *file_priv,
return err;
}
+void xe_bo_runtime_pm_release_mmap_offset(struct xe_bo *bo)
+{
+ struct ttm_buffer_object *tbo = &bo->ttm;
+ struct ttm_device *bdev = tbo->bdev;
+ struct xe_device *xe = ttm_to_xe_device(bdev);
+
+ drm_vma_node_unmap(&tbo->base.vma_node, bdev->dev_mapping);
+
+ /*
+ * Other callers xe_ttm_bo_destroy and xe_bo_move_notify also checks and
+ * deletes vram_user_fault_link so grabbing spinlock here.
+ */
+ XE_WARN_ON(!bo->vram_userfault_count);
+ spin_lock(&xe->mem_access.vram_userfault_lock);
+ list_del(&bo->vram_userfault_link);
+ bo->vram_userfault_count = 0;
+ spin_unlock(&xe->mem_access.vram_userfault_lock);
+}
+
#if IS_ENABLED(CONFIG_DRM_XE_KUNIT_TEST)
#include "tests/xe_bo.c"
#endif
diff --git a/drivers/gpu/drm/xe/xe_bo.h b/drivers/gpu/drm/xe/xe_bo.h
index 97b32528c600..350cc73cadf8 100644
--- a/drivers/gpu/drm/xe/xe_bo.h
+++ b/drivers/gpu/drm/xe/xe_bo.h
@@ -249,6 +249,8 @@ int xe_gem_create_ioctl(struct drm_device *dev, void *data,
struct drm_file *file);
int xe_gem_mmap_offset_ioctl(struct drm_device *dev, void *data,
struct drm_file *file);
+void xe_bo_runtime_pm_release_mmap_offset(struct xe_bo *bo);
+
int xe_bo_dumb_create(struct drm_file *file_priv,
struct drm_device *dev,
struct drm_mode_create_dumb *args);
diff --git a/drivers/gpu/drm/xe/xe_bo_types.h b/drivers/gpu/drm/xe/xe_bo_types.h
index 64c2249a4e40..910b35c05acd 100644
--- a/drivers/gpu/drm/xe/xe_bo_types.h
+++ b/drivers/gpu/drm/xe/xe_bo_types.h
@@ -88,6 +88,11 @@ struct xe_bo {
* objects.
*/
u16 cpu_caching;
+ /**
+ * Whether the object is currently in fake offset mmap backed by vram.
+ */
+ unsigned int vram_userfault_count;
+ struct list_head vram_userfault_link;
};
#define intel_bo_to_drm_bo(bo) (&(bo)->ttm.base)
diff --git a/drivers/gpu/drm/xe/xe_device_types.h b/drivers/gpu/drm/xe/xe_device_types.h
index 71f23ac365e6..6890d21f7a4c 100644
--- a/drivers/gpu/drm/xe/xe_device_types.h
+++ b/drivers/gpu/drm/xe/xe_device_types.h
@@ -385,6 +385,26 @@ struct xe_device {
struct {
/** @ref: ref count of memory accesses */
atomic_t ref;
+ /*
+ * Protects access to vram usefault list.
+ * It is required, if we are outside of the runtime suspend path,
+ * access to @vram_userfault_list requires always first grabbing the
+ * runtime pm, to ensure we can't race against runtime suspend.
+ * Once we have that we also need to grab @vram_userfault_lock,
+ * at which point we have exclusive access.
+ * The runtime suspend path is special since it doesn't really hold any locks,
+ * but instead has exclusive access by virtue of all other accesses requiring
+ * holding the runtime pm wakeref.
+ */
+ spinlock_t vram_userfault_lock;
+
+ /*
+ * Keep list of userfaulted gem obj, which require to release their
+ * mmap mappings at runtime suspend path.
+ */
+ struct list_head vram_userfault_list;
+
+ bool vram_userfault_ongoing;
} mem_access;
/**
diff --git a/drivers/gpu/drm/xe/xe_pm.c b/drivers/gpu/drm/xe/xe_pm.c
index b429c2876a76..bc1cb081e6e5 100644
--- a/drivers/gpu/drm/xe/xe_pm.c
+++ b/drivers/gpu/drm/xe/xe_pm.c
@@ -181,6 +181,8 @@ void xe_pm_init(struct xe_device *xe)
}
xe_pm_runtime_init(xe);
+ INIT_LIST_HEAD(&xe->mem_access.vram_userfault_list);
+ spin_lock_init(&xe->mem_access.vram_userfault_lock);
}
void xe_pm_runtime_fini(struct xe_device *xe)
@@ -214,6 +216,7 @@ struct task_struct *xe_pm_read_callback_task(struct xe_device *xe)
int xe_pm_runtime_suspend(struct xe_device *xe)
{
+ struct xe_bo *bo, *on;
struct xe_gt *gt;
u8 id;
int err = 0;
@@ -247,6 +250,10 @@ int xe_pm_runtime_suspend(struct xe_device *xe)
*/
lock_map_acquire(&xe_device_mem_access_lockdep_map);
+ list_for_each_entry_safe(bo, on,
+ &xe->mem_access.vram_userfault_list, vram_userfault_link)
+ xe_bo_runtime_pm_release_mmap_offset(bo);
+
if (xe->d3cold.allowed) {
err = xe_bo_evict_all(xe);
if (err)
--
2.25.1
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