[PATCH 55/56] drm/i915: Track userptr VMAs

[Ben Widawsky <benjamin.widawsky@intel.com>]

This HACK allows users to reuse the userptr ioctl in order to
pre-reserve the VMA at a specific location. The vma will follow all the
same paths as other userptr objects - only the drm_mm node is actually
allocated.

Again, this patch is a big HACK to get some other people currently using
userptr enabled.

Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
---
 drivers/gpu/drm/i915/i915_drv.h            |  1 +
 drivers/gpu/drm/i915/i915_gem.c            | 22 +++++++++++++++++++---
 drivers/gpu/drm/i915/i915_gem_execbuffer.c |  3 +++
 drivers/gpu/drm/i915/i915_gem_gtt.h        |  4 ++++
 4 files changed, 27 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 60513e7..71e39ff 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -2166,6 +2166,7 @@ void i915_gem_vma_destroy(struct i915_vma *vma);
 #define PIN_GLOBAL 0x4
 #define PIN_ALIASING 0x8
 #define PIN_GLOBAL_ALIASED (PIN_ALIASING | PIN_GLOBAL)
+#define PIN_BOUND	0x10
 int __must_check i915_gem_object_pin(struct drm_i915_gem_object *obj,
 				     struct i915_address_space *vm,
 				     uint32_t alignment,
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 287d48e..ff75971 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -3279,7 +3279,13 @@ i915_gem_object_bind_to_vm(struct drm_i915_gem_object *obj,
 	if (IS_ERR(vma))
 		goto err_unpin;
 
+	if (flags & PIN_BOUND) {
+		WARN_ON(!vma->node.allocated && !vma->obj->userptr.ptr);
+		goto skip_search;
+	}
+
 search_free:
+	WARN_ON(vma->node.allocated);
 	ret = drm_mm_insert_node_in_range_generic(&vm->mm, &vma->node,
 						  size, alignment,
 						  obj->cache_level, 0, gtt_max,
@@ -3293,6 +3299,7 @@ search_free:
 
 		goto err_free_vma;
 	}
+skip_search:
 	if (WARN_ON(!i915_gem_valid_gtt_space(dev, &vma->node,
 					      obj->cache_level))) {
 		ret = -EINVAL;
@@ -3329,10 +3336,13 @@ search_free:
 	i915_gem_vma_bind(vma, obj->cache_level, vma_bind_flags);
 
 	i915_gem_verify_gtt(dev);
+	if (flags & PIN_BOUND)
+		vma->uptr_bind=1;
 	return vma;
 
 err_remove_node:
-	drm_mm_remove_node(&vma->node);
+	if ((flags & PIN_BOUND) == 0)
+		drm_mm_remove_node(&vma->node);
 err_free_vma:
 	i915_gem_vma_destroy(vma);
 	vma = ERR_PTR(ret);
@@ -3875,6 +3885,11 @@ i915_gem_object_pin(struct drm_i915_gem_object *obj,
 	if (WARN_ON(flags & (PIN_GLOBAL | PIN_MAPPABLE) && !i915_is_ggtt(vm)))
 		return -EINVAL;
 
+	if (flags & PIN_BOUND) {
+		if (WARN_ON(flags & ~PIN_BOUND))
+			return -EINVAL;
+	}
+
 	vma = i915_gem_obj_to_vma(obj, vm);
 	if (vma) {
 		if (WARN_ON(vma->pin_count == DRM_I915_GEM_OBJECT_MAX_PIN_COUNT))
@@ -3898,7 +3913,8 @@ i915_gem_object_pin(struct drm_i915_gem_object *obj,
 		}
 	}
 
-	if (vma == NULL || !drm_mm_node_allocated(&vma->node)) {
+	if (vma == NULL || !drm_mm_node_allocated(&vma->node) ||
+	    ((flags & PIN_BOUND) && !vma->uptr_bind)) {
 		vma = i915_gem_object_bind_to_vm(obj, vm, alignment, flags);
 		if (IS_ERR(vma))
 			return PTR_ERR(vma);
@@ -4265,7 +4281,7 @@ struct i915_vma *i915_gem_obj_to_vma(struct drm_i915_gem_object *obj,
 
 void i915_gem_vma_destroy(struct i915_vma *vma)
 {
-	WARN_ON(vma->node.allocated);
+	WARN_ON(vma->node.allocated && !vma->uptr);
 
 	/* Keep the vma as a placeholder in the execbuffer reservation lists */
 	if (!list_empty(&vma->exec_list))
diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
index 08fde7d..596e51e 100644
--- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
@@ -566,6 +566,9 @@ i915_gem_execbuffer_reserve_vma(struct i915_vma *vma,
 	if (entry->flags & EXEC_OBJECT_NEEDS_GTT)
 		flags |= PIN_GLOBAL;
 
+	if (vma->uptr)
+		flags |= PIN_BOUND;
+
 	ret = i915_gem_object_pin(obj, vma->vm, entry->alignment, flags);
 	if (ret)
 		return ret;
diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.h b/drivers/gpu/drm/i915/i915_gem_gtt.h
index c265c23..bdb4b05 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.h
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.h
@@ -171,6 +171,10 @@ struct i915_vma {
 	unsigned int pin_count:4;
 #define DRM_I915_GEM_OBJECT_MAX_PIN_COUNT 0xf
 
+	/* FIXME: */
+	unsigned int uptr:1; /* Whether this VMA has been userptr'd */
+	unsigned int uptr_bind:1; /* Whether we've actually bound it */
+
 	/** Unmap an object from an address space. This usually consists of
 	 * setting the valid PTE entries to a reserved scratch page. */
 	void (*unbind_vma)(struct i915_vma *vma);
-- 
1.9.2