drm/msm: drm_gpuvm conversion

Now that we've realigned deletion and allocation, switch over to using
drm_gpuvm/drm_gpuva.  This allows us to support multiple VMAs per BO per
VM, to allow mapping different parts of a single BO at different virtual
addresses, which is a key requirement for sparse/VM_BIND.

This prepares us for using drm_gpuvm to translate a batch of MAP/
MAP_NULL/UNMAP operations from userspace into a sequence of map/remap/
unmap steps for updating the page tables.

Since, unlike our prior vm/vma setup, with drm_gpuvm the vm_bo holds a
reference to the GEM object.  To prevent reference loops causing us to
leak all GEM objects, we implicitly tear down the mapping when the GEM
handle is close or when the obj is unpinned.  Which means the submit
needs to also hold a reference to the vm_bo, to prevent the VMA from
being torn down while the submit is in-flight.

Signed-off-by: Rob Clark <robdclark@chromium.org>
Signed-off-by: Rob Clark <robin.clark@oss.qualcomm.com>
Tested-by: Antonino Maniscalco <antomani103@gmail.com>
Reviewed-by: Antonino Maniscalco <antomani103@gmail.com>
Patchwork: https://patchwork.freedesktop.org/patch/661479/

1 files changed, 107 insertions, 59 deletions

diff --git a/drivers/gpu/drm/msm/msm_gem.c b/drivers/gpu/drm/msm/msm_gem.c
index a20ae783f244..664fb801c221 100644
--- a/drivers/gpu/drm/msm/msm_gem.c
+++ b/drivers/gpu/drm/msm/msm_gem.c
@@ -43,9 +43,53 @@ static int msm_gem_open(struct drm_gem_object *obj, struct drm_file *file)
 	return 0;
 }
 
+static void put_iova_spaces(struct drm_gem_object *obj, struct drm_gpuvm *vm, bool close);
+
+static void detach_vm(struct drm_gem_object *obj, struct msm_gem_vm *vm)
+{
+	msm_gem_assert_locked(obj);
+
+	struct drm_gpuvm_bo *vm_bo = drm_gpuvm_bo_find(&vm->base, obj);
+	if (vm_bo) {
+		struct drm_gpuva *vma;
+
+		drm_gpuvm_bo_for_each_va (vma, vm_bo) {
+			if (vma->vm != &vm->base)
+				continue;
+			msm_gem_vma_purge(to_msm_vma(vma));
+			msm_gem_vma_close(to_msm_vma(vma));
+			break;
+		}
+
+		drm_gpuvm_bo_put(vm_bo);
+	}
+}
+
 static void msm_gem_close(struct drm_gem_object *obj, struct drm_file *file)
 {
+	struct msm_context *ctx = file->driver_priv;
+
 	update_ctx_mem(file, -obj->size);
+
+	/*
+	 * If VM isn't created yet, nothing to cleanup.  And in fact calling
+	 * put_iova_spaces() with vm=NULL would be bad, in that it will tear-
+	 * down the mappings of shared buffers in other contexts.
+	 */
+	if (!ctx->vm)
+		return;
+
+	/*
+	 * TODO we might need to kick this to a queue to avoid blocking
+	 * in CLOSE ioctl
+	 */
+	dma_resv_wait_timeout(obj->resv, DMA_RESV_USAGE_READ, false,
+			      msecs_to_jiffies(1000));
+
+	msm_gem_lock(obj);
+	put_iova_spaces(obj, &ctx->vm->base, true);
+	detach_vm(obj, ctx->vm);
+	msm_gem_unlock(obj);
 }
 
 /*
@@ -167,6 +211,13 @@ static void put_pages(struct drm_gem_object *obj)
 {
 	struct msm_gem_object *msm_obj = to_msm_bo(obj);
 
+	/*
+	 * Skip gpuvm in the object free path to avoid a WARN_ON() splat.
+	 * See explaination in msm_gem_assert_locked()
+	 */
+	if (kref_read(&obj->refcount))
+		drm_gpuvm_bo_gem_evict(obj, true);
+
 	if (msm_obj->pages) {
 		if (msm_obj->sgt) {
 			/* For non-cached buffers, ensure the new
@@ -334,16 +385,25 @@ uint64_t msm_gem_mmap_offset(struct drm_gem_object *obj)
 }
 
 static struct msm_gem_vma *lookup_vma(struct drm_gem_object *obj,
-		struct msm_gem_vm *vm)
+				      struct msm_gem_vm *vm)
 {
-	struct msm_gem_object *msm_obj = to_msm_bo(obj);
-	struct msm_gem_vma *vma;
+	struct drm_gpuvm_bo *vm_bo;
 
 	msm_gem_assert_locked(obj);
 
-	list_for_each_entry(vma, &msm_obj->vmas, list) {
-		if (vma->vm == vm)
-			return vma;
+	drm_gem_for_each_gpuvm_bo (vm_bo, obj) {
+		struct drm_gpuva *vma;
+
+		drm_gpuvm_bo_for_each_va (vma, vm_bo) {
+			if (vma->vm == &vm->base) {
+				/* lookup_vma() should only be used in paths
+				 * with at most one vma per vm
+				 */
+				GEM_WARN_ON(!list_is_singular(&vm_bo->list.gpuva));
+
+				return to_msm_vma(vma);
+			}
+		}
 	}
 
 	return NULL;
@@ -356,33 +416,29 @@ static struct msm_gem_vma *lookup_vma(struct drm_gem_object *obj,
  * mapping.
  */
 static void
-put_iova_spaces(struct drm_gem_object *obj, bool close)
+put_iova_spaces(struct drm_gem_object *obj, struct drm_gpuvm *vm, bool close)
 {
-	struct msm_gem_object *msm_obj = to_msm_bo(obj);
-	struct msm_gem_vma *vma, *tmp;
+	struct drm_gpuvm_bo *vm_bo, *tmp;
 
 	msm_gem_assert_locked(obj);
 
-	list_for_each_entry_safe(vma, tmp, &msm_obj->vmas, list) {
-		if (vma->vm) {
-			msm_gem_vma_purge(vma);
-			if (close)
-				msm_gem_vma_close(vma);
-		}
-	}
-}
+	drm_gem_for_each_gpuvm_bo_safe (vm_bo, tmp, obj) {
+		struct drm_gpuva *vma, *vmatmp;
 
-/* Called with msm_obj locked */
-static void
-put_iova_vmas(struct drm_gem_object *obj)
-{
-	struct msm_gem_object *msm_obj = to_msm_bo(obj);
-	struct msm_gem_vma *vma, *tmp;
+		if (vm && vm_bo->vm != vm)
+			continue;
 
-	msm_gem_assert_locked(obj);
+		drm_gpuvm_bo_get(vm_bo);
+
+		drm_gpuvm_bo_for_each_va_safe (vma, vmatmp, vm_bo) {
+			struct msm_gem_vma *msm_vma = to_msm_vma(vma);
+
+			msm_gem_vma_purge(msm_vma);
+			if (close)
+				msm_gem_vma_close(msm_vma);
+		}
 
-	list_for_each_entry_safe(vma, tmp, &msm_obj->vmas, list) {
-		msm_gem_vma_close(vma);
+		drm_gpuvm_bo_put(vm_bo);
 	}
 }
 
@@ -390,7 +446,6 @@ static struct msm_gem_vma *get_vma_locked(struct drm_gem_object *obj,
 		struct msm_gem_vm *vm,
 		u64 range_start, u64 range_end)
 {
-	struct msm_gem_object *msm_obj = to_msm_bo(obj);
 	struct msm_gem_vma *vma;
 
 	msm_gem_assert_locked(obj);
@@ -399,12 +454,9 @@ static struct msm_gem_vma *get_vma_locked(struct drm_gem_object *obj,
 
 	if (!vma) {
 		vma = msm_gem_vma_new(vm, obj, range_start, range_end);
-		if (IS_ERR(vma))
-			return vma;
-		list_add_tail(&vma->list, &msm_obj->vmas);
 	} else {
-		GEM_WARN_ON(vma->iova < range_start);
-		GEM_WARN_ON((vma->iova + obj->size) > range_end);
+		GEM_WARN_ON(vma->base.va.addr < range_start);
+		GEM_WARN_ON((vma->base.va.addr + obj->size) > range_end);
 	}
 
 	return vma;
@@ -484,7 +536,7 @@ static int get_and_pin_iova_range_locked(struct drm_gem_object *obj,
 
 	ret = msm_gem_pin_vma_locked(obj, vma);
 	if (!ret) {
-		*iova = vma->iova;
+		*iova = vma->base.va.addr;
 		pin_obj_locked(obj);
 	}
 
@@ -530,7 +582,7 @@ int msm_gem_get_iova(struct drm_gem_object *obj,
 	if (IS_ERR(vma)) {
 		ret = PTR_ERR(vma);
 	} else {
-		*iova = vma->iova;
+		*iova = vma->base.va.addr;
 	}
 	msm_gem_unlock(obj);
 
@@ -571,7 +623,7 @@ int msm_gem_set_iova(struct drm_gem_object *obj,
 		vma = get_vma_locked(obj, vm, iova, iova + obj->size);
 		if (IS_ERR(vma)) {
 			ret = PTR_ERR(vma);
-		} else if (GEM_WARN_ON(vma->iova != iova)) {
+		} else if (GEM_WARN_ON(vma->base.va.addr != iova)) {
 			clear_iova(obj, vm);
 			ret = -EBUSY;
 		}
@@ -593,9 +645,10 @@ void msm_gem_unpin_iova(struct drm_gem_object *obj,
 
 	msm_gem_lock(obj);
 	vma = lookup_vma(obj, vm);
-	if (!GEM_WARN_ON(!vma)) {
+	if (vma) {
 		msm_gem_unpin_locked(obj);
 	}
+	detach_vm(obj, vm);
 	msm_gem_unlock(obj);
 }
 
@@ -755,7 +808,7 @@ void msm_gem_purge(struct drm_gem_object *obj)
 	GEM_WARN_ON(!is_purgeable(msm_obj));
 
 	/* Get rid of any iommu mapping(s): */
-	put_iova_spaces(obj, false);
+	put_iova_spaces(obj, NULL, false);
 
 	msm_gem_vunmap(obj);
 
@@ -763,8 +816,6 @@ void msm_gem_purge(struct drm_gem_object *obj)
 
 	put_pages(obj);
 
-	put_iova_vmas(obj);
-
 	mutex_lock(&priv->lru.lock);
 	/* A one-way transition: */
 	msm_obj->madv = __MSM_MADV_PURGED;
@@ -795,7 +846,7 @@ void msm_gem_evict(struct drm_gem_object *obj)
 	GEM_WARN_ON(is_unevictable(msm_obj));
 
 	/* Get rid of any iommu mapping(s): */
-	put_iova_spaces(obj, false);
+	put_iova_spaces(obj, NULL, false);
 
 	drm_vma_node_unmap(&obj->vma_node, dev->anon_inode->i_mapping);
 
@@ -861,7 +912,6 @@ void msm_gem_describe(struct drm_gem_object *obj, struct seq_file *m,
 {
 	struct msm_gem_object *msm_obj = to_msm_bo(obj);
 	struct dma_resv *robj = obj->resv;
-	struct msm_gem_vma *vma;
 	uint64_t off = drm_vma_node_start(&obj->vma_node);
 	const char *madv;
 
@@ -904,14 +954,17 @@ void msm_gem_describe(struct drm_gem_object *obj, struct seq_file *m,
 
 	seq_printf(m, " %08zu %9s %-32s\n", obj->size, madv, msm_obj->name);
 
-	if (!list_empty(&msm_obj->vmas)) {
+	if (!list_empty(&obj->gpuva.list)) {
+		struct drm_gpuvm_bo *vm_bo;
 
 		seq_puts(m, "      vmas:");
 
-		list_for_each_entry(vma, &msm_obj->vmas, list) {
-			const char *name, *comm;
-			if (vma->vm) {
-				struct msm_gem_vm *vm = vma->vm;
+		drm_gem_for_each_gpuvm_bo (vm_bo, obj) {
+			struct drm_gpuva *vma;
+
+			drm_gpuvm_bo_for_each_va (vma, vm_bo) {
+				const char *name, *comm;
+				struct msm_gem_vm *vm = to_msm_vm(vma->vm);
 				struct task_struct *task =
 					get_pid_task(vm->pid, PIDTYPE_PID);
 				if (task) {
@@ -920,15 +973,14 @@ void msm_gem_describe(struct drm_gem_object *obj, struct seq_file *m,
 				} else {
 					comm = NULL;
 				}
-				name = vm->name;
-			} else {
-				name = comm = NULL;
+				name = vm->base.name;
+
+				seq_printf(m, " [%s%s%s: vm=%p, %08llx, %smapped]",
+					   name, comm ? ":" : "", comm ? comm : "",
+					   vma->vm, vma->va.addr,
+					   to_msm_vma(vma)->mapped ? "" : "un");
+				kfree(comm);
 			}
-			seq_printf(m, " [%s%s%s: vm=%p, %08llx,%s]",
-				name, comm ? ":" : "", comm ? comm : "",
-				vma->vm, vma->iova,
-				vma->mapped ? "mapped" : "unmapped");
-			kfree(comm);
 		}
 
 		seq_puts(m, "\n");
@@ -974,7 +1026,7 @@ static void msm_gem_free_object(struct drm_gem_object *obj)
 	list_del(&msm_obj->node);
 	mutex_unlock(&priv->obj_lock);
 
-	put_iova_spaces(obj, true);
+	put_iova_spaces(obj, NULL, true);
 
 	if (drm_gem_is_imported(obj)) {
 		GEM_WARN_ON(msm_obj->vaddr);
@@ -984,13 +1036,10 @@ static void msm_gem_free_object(struct drm_gem_object *obj)
 		 */
 		kvfree(msm_obj->pages);
 
-		put_iova_vmas(obj);
-
 		drm_prime_gem_destroy(obj, msm_obj->sgt);
 	} else {
 		msm_gem_vunmap(obj);
 		put_pages(obj);
-		put_iova_vmas(obj);
 	}
 
 	drm_gem_object_release(obj);
@@ -1096,7 +1145,6 @@ static int msm_gem_new_impl(struct drm_device *dev,
 	msm_obj->madv = MSM_MADV_WILLNEED;
 
 	INIT_LIST_HEAD(&msm_obj->node);
-	INIT_LIST_HEAD(&msm_obj->vmas);
 
 	*obj = &msm_obj->base;
 	(*obj)->funcs = &msm_gem_object_funcs;