[PATCH] drm/amdgpu: use HMM mirror callback to replace mmu notifier v3

Philip Yang Philip.Yang at amd.com
Thu Sep 13 18:00:40 UTC 2018


Replace our MMU notifier with hmm_mirror_ops.sync_cpu_device_pagetables
callback. Enable CONFIG_HMM and CONFIG_HMM_MIRROR as a dependency in
DRM_AMDGPU_USERPTR Kconfig.

It supports both KFD userptr and gfx userptr paths.

This depends on several HMM patchset from Jérôme Glisse queued for
upstream. See
http://172.27.226.38/root/kernel_amd/commits/hmm-dev-v01 (for AMD intranet)

Change-Id: Ie62c3c5e3c5b8521ab3b438d1eff2aa2a003835e
Signed-off-by: Philip Yang <Philip.Yang at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/Kconfig     |  6 +--
 drivers/gpu/drm/amd/amdgpu/Makefile    |  2 +-
 drivers/gpu/drm/amd/amdgpu/amdgpu_mn.c | 88 +++++++++++++++++++++++++++-------
 3 files changed, 75 insertions(+), 21 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/Kconfig b/drivers/gpu/drm/amd/amdgpu/Kconfig
index 9221e54..960a633 100644
--- a/drivers/gpu/drm/amd/amdgpu/Kconfig
+++ b/drivers/gpu/drm/amd/amdgpu/Kconfig
@@ -26,10 +26,10 @@ config DRM_AMDGPU_CIK
 config DRM_AMDGPU_USERPTR
 	bool "Always enable userptr write support"
 	depends on DRM_AMDGPU
-	select MMU_NOTIFIER
+	select HMM_MIRROR
 	help
-	  This option selects CONFIG_MMU_NOTIFIER if it isn't already
-	  selected to enabled full userptr support.
+	  This option selects CONFIG_HMM and CONFIG_HMM_MIRROR if it
+	  isn't already selected to enabled full userptr support.
 
 config DRM_AMDGPU_GART_DEBUGFS
 	bool "Allow GART access through debugfs"
diff --git a/drivers/gpu/drm/amd/amdgpu/Makefile b/drivers/gpu/drm/amd/amdgpu/Makefile
index 138cb78..c1e5d43 100644
--- a/drivers/gpu/drm/amd/amdgpu/Makefile
+++ b/drivers/gpu/drm/amd/amdgpu/Makefile
@@ -171,7 +171,7 @@ endif
 amdgpu-$(CONFIG_COMPAT) += amdgpu_ioc32.o
 amdgpu-$(CONFIG_VGA_SWITCHEROO) += amdgpu_atpx_handler.o
 amdgpu-$(CONFIG_ACPI) += amdgpu_acpi.o
-amdgpu-$(CONFIG_MMU_NOTIFIER) += amdgpu_mn.o
+amdgpu-$(CONFIG_HMM) += amdgpu_mn.o
 
 include $(FULL_AMD_PATH)/powerplay/Makefile
 
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_mn.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_mn.c
index e55508b..ea8671f6 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_mn.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_mn.c
@@ -46,6 +46,7 @@
 #include <linux/firmware.h>
 #include <linux/module.h>
 #include <linux/mmu_notifier.h>
+#include <linux/hmm.h>
 #include <linux/interval_tree.h>
 #include <drm/drmP.h>
 #include <drm/drm.h>
@@ -66,6 +67,7 @@
  * @objects: interval tree containing amdgpu_mn_nodes
  * @read_lock: mutex for recursive locking of @lock
  * @recursion: depth of recursion
+ * @mirror: HMM mirror function support
  *
  * Data for each amdgpu device and process address space.
  */
@@ -87,6 +89,9 @@ struct amdgpu_mn {
 	struct rb_root_cached	objects;
 	struct mutex		read_lock;
 	atomic_t		recursion;
+
+	/* HMM mirror */
+	struct hmm_mirror	mirror;
 };
 
 /**
@@ -103,7 +108,7 @@ struct amdgpu_mn_node {
 };
 
 /**
- * amdgpu_mn_destroy - destroy the MMU notifier
+ * amdgpu_mn_destroy - destroy the HMM mirror
  *
  * @work: previously sheduled work item
  *
@@ -129,28 +134,27 @@ static void amdgpu_mn_destroy(struct work_struct *work)
 	}
 	up_write(&amn->lock);
 	mutex_unlock(&adev->mn_lock);
-	mmu_notifier_unregister_no_release(&amn->mn, amn->mm);
+
+	hmm_mirror_unregister(&amn->mirror);
+
 	kfree(amn);
 }
 
 /**
  * amdgpu_mn_release - callback to notify about mm destruction
  *
- * @mn: our notifier
- * @mm: the mm this callback is about
+ * @mirror: the HMM mirror (mm) this callback is about
  *
- * Shedule a work item to lazy destroy our notifier.
+ * Shedule a work item to lazy destroy HMM mirror.
  */
-static void amdgpu_mn_release(struct mmu_notifier *mn,
-			      struct mm_struct *mm)
+static void amdgpu_hmm_mirror_release(struct hmm_mirror *mirror)
 {
-	struct amdgpu_mn *amn = container_of(mn, struct amdgpu_mn, mn);
+	struct amdgpu_mn *amn = container_of(mirror, struct amdgpu_mn, mirror);
 
 	INIT_WORK(&amn->work, amdgpu_mn_destroy);
 	schedule_work(&amn->work);
 }
 
-
 /**
  * amdgpu_mn_lock - take the write side lock for this notifier
  *
@@ -355,12 +359,10 @@ static void amdgpu_mn_invalidate_range_end(struct mmu_notifier *mn,
 
 static const struct mmu_notifier_ops amdgpu_mn_ops[] = {
 	[AMDGPU_MN_TYPE_GFX] = {
-		.release = amdgpu_mn_release,
 		.invalidate_range_start = amdgpu_mn_invalidate_range_start_gfx,
 		.invalidate_range_end = amdgpu_mn_invalidate_range_end,
 	},
 	[AMDGPU_MN_TYPE_HSA] = {
-		.release = amdgpu_mn_release,
 		.invalidate_range_start = amdgpu_mn_invalidate_range_start_hsa,
 		.invalidate_range_end = amdgpu_mn_invalidate_range_end,
 	},
@@ -373,12 +375,63 @@ static const struct mmu_notifier_ops amdgpu_mn_ops[] = {
 #define AMDGPU_MN_KEY(mm, type) ((unsigned long)(mm) + (type))
 
 /**
- * amdgpu_mn_get - create notifier context
+ * amdgpu_hmm_sync_cpu_device_pagetables - synchronize CPU/GPU page tables
+ *
+ * @mirror: the hmm_mirror (mm) is about to update
+ * @update: the update start, end address
+ *
+ * This callback is called from mmu_notifiers when the CPU page table is
+ * updated.
+ */
+static int amdgpu_hmm_sync_cpu_device_pagetables(struct hmm_mirror *mirror,
+			const struct hmm_update *update)
+{
+	struct amdgpu_mn *amn;
+	struct hmm *hmm;
+	struct mm_struct *mm;
+	unsigned long start;
+	unsigned long end;
+	unsigned long key;
+	int r = 0;
+
+	start = update->start;
+	end = update->end;
+	hmm = mirror->hmm;
+	mm = *(struct mm_struct **)hmm;
+
+	pr_debug("mirror %p start %lx end %lx\n", mirror, start, end);
+
+	amn = container_of(mirror, struct amdgpu_mn, mirror);
+	key = AMDGPU_MN_KEY(mm, amn->type);
+
+	hash_for_each_possible(amn->adev->mn_hash, amn, node, key)
+		if (AMDGPU_MN_KEY(amn->mm, amn->type) == key) {
+			r = amn->mn.ops->invalidate_range_start(&amn->mn, mm,
+							start, end,
+							update->blockable);
+			amn->mn.ops->invalidate_range_end(&amn->mn, mm,
+							start, end);
+			if (r) {
+				DRM_ERROR("Failed to invalidate %lx\n", start);
+				break;
+			}
+		}
+
+	return r;
+}
+
+static struct hmm_mirror_ops amdgpu_hmm_mirror_ops = {
+	.sync_cpu_device_pagetables = amdgpu_hmm_sync_cpu_device_pagetables,
+	.release = amdgpu_hmm_mirror_release
+};
+
+/**
+ * amdgpu_mn_get - create HMM mirror context
  *
  * @adev: amdgpu device pointer
  * @type: type of MMU notifier context
  *
- * Creates a notifier context for current->mm.
+ * Creates a HMM mirror context for current->mm.
  */
 struct amdgpu_mn *amdgpu_mn_get(struct amdgpu_device *adev,
 				enum amdgpu_mn_type type)
@@ -413,7 +466,8 @@ struct amdgpu_mn *amdgpu_mn_get(struct amdgpu_device *adev,
 	mutex_init(&amn->read_lock);
 	atomic_set(&amn->recursion, 0);
 
-	r = __mmu_notifier_register(&amn->mn, mm);
+	amn->mirror.ops = &amdgpu_hmm_mirror_ops;
+	r = hmm_mirror_register(&amn->mirror, mm);
 	if (r)
 		goto free_amn;
 
@@ -439,7 +493,7 @@ struct amdgpu_mn *amdgpu_mn_get(struct amdgpu_device *adev,
  * @bo: amdgpu buffer object
  * @addr: userptr addr we should monitor
  *
- * Registers an MMU notifier for the given BO at the specified address.
+ * Registers an HMM mirror for the given BO at the specified address.
  * Returns 0 on success, -ERRNO if anything goes wrong.
  */
 int amdgpu_mn_register(struct amdgpu_bo *bo, unsigned long addr)
@@ -495,11 +549,11 @@ int amdgpu_mn_register(struct amdgpu_bo *bo, unsigned long addr)
 }
 
 /**
- * amdgpu_mn_unregister - unregister a BO for notifier updates
+ * amdgpu_mn_unregister - unregister a BO for HMM mirror updates
  *
  * @bo: amdgpu buffer object
  *
- * Remove any registration of MMU notifier updates from the buffer object.
+ * Remove any registration of HMM mirror updates from the buffer object.
  */
 void amdgpu_mn_unregister(struct amdgpu_bo *bo)
 {
-- 
2.7.4



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