drm/vmwgfx: Implement DRIVER_GEM

This is initial change adding support for DRIVER_GEM to vmwgfx. vmwgfx
was written before GEM and has always used TTM. Over the years the
TTM buffers started inherting from GEM objects but vmwgfx never
implemented GEM making it quite awkward. We were directly setting
variables in GEM objects to not make DRM crash.

This change brings vmwgfx inline with other DRM drivers and allows us
to use a lot of DRM helpers which have depended on drivers with GEM
support.

Due to historical reasons vmwgfx splits the idea of a buffer and surface
which makes it a littly tricky since either one can be used in most
of our ioctl's which take user space handles. For now our BO's are
GEM objects and our surfaces are opaque objects which are backed by
GEM objects. In the future I'd like to combine those into a single
BO but we don't want to break any of our existing ioctl's so it will
take time to do it in a non-destructive way.

Signed-off-by: Zack Rusin <zackr@vmware.com>
Reviewed-by: Martin Krastev <krastevm@vmware.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211206172620.3139754-5-zack@kde.org

Author: zackr

drivers/gpu/drm/vmwgfx/Kconfig

@@ -4,6 +4,7 @@ config DRM_VMWGFX
 	depends on DRM && PCI && MMU
 	depends on X86 || ARM64
 	select DRM_TTM
+	select DRM_TTM_HELPER
 	select MAPPING_DIRTY_HELPERS
 	# Only needed for the transitional use of drm_crtc_init - can be removed
 	# again once vmwgfx sets up the primary plane itself.

drivers/gpu/drm/vmwgfx/Makefile

@@ -9,7 +9,8 @@ vmwgfx-y := vmwgfx_execbuf.o vmwgfx_gmr.o vmwgfx_hashtab.o vmwgfx_kms.o vmwgfx_d
 	    vmwgfx_cotable.o vmwgfx_so.o vmwgfx_binding.o vmwgfx_msg.o \
 	    vmwgfx_simple_resource.o vmwgfx_va.o vmwgfx_blit.o \
 	    vmwgfx_validation.o vmwgfx_page_dirty.o vmwgfx_streamoutput.o \
-	    vmwgfx_devcaps.o ttm_object.o vmwgfx_system_manager.o
+	    vmwgfx_devcaps.o ttm_object.o vmwgfx_system_manager.o \
+	    vmwgfx_gem.o
 
 vmwgfx-$(CONFIG_DRM_FBDEV_EMULATION) += vmwgfx_fb.o
 vmwgfx-$(CONFIG_TRANSPARENT_HUGEPAGE) += vmwgfx_thp.o

drivers/gpu/drm/vmwgfx/ttm_object.c

@@ -50,6 +50,7 @@
 #include <linux/atomic.h>
 #include <linux/module.h>
 #include "ttm_object.h"
+#include "vmwgfx_drv.h"
 
 MODULE_IMPORT_NS(DMA_BUF);
 
@@ -73,7 +74,7 @@ struct ttm_object_file {
 	struct ttm_object_device *tdev;
 	spinlock_t lock;
 	struct list_head ref_list;
-	struct vmwgfx_open_hash ref_hash[TTM_REF_NUM];
+	struct vmwgfx_open_hash ref_hash;
 	struct kref refcount;
 };
 
@@ -124,7 +125,6 @@ struct ttm_ref_object {
 	struct vmwgfx_hash_item hash;
 	struct list_head head;
 	struct kref kref;
-	enum ttm_ref_type ref_type;
 	struct ttm_base_object *obj;
 	struct ttm_object_file *tfile;
 };
@@ -160,17 +160,14 @@ int ttm_base_object_init(struct ttm_object_file *tfile,
 			 struct ttm_base_object *base,
 			 bool shareable,
 			 enum ttm_object_type object_type,
-			 void (*refcount_release) (struct ttm_base_object **),
-			 void (*ref_obj_release) (struct ttm_base_object *,
-						  enum ttm_ref_type ref_type))
+			 void (*refcount_release) (struct ttm_base_object **))
 {
 	struct ttm_object_device *tdev = tfile->tdev;
 	int ret;
 
 	base->shareable = shareable;
 	base->tfile = ttm_object_file_ref(tfile);
 	base->refcount_release = refcount_release;
-	base->ref_obj_release = ref_obj_release;
 	base->object_type = object_type;
 	kref_init(&base->refcount);
 	idr_preload(GFP_KERNEL);
@@ -182,7 +179,7 @@ int ttm_base_object_init(struct ttm_object_file *tfile,
 		return ret;
 
 	base->handle = ret;
-	ret = ttm_ref_object_add(tfile, base, TTM_REF_USAGE, NULL, false);
+	ret = ttm_ref_object_add(tfile, base, NULL, false);
 	if (unlikely(ret != 0))
 		goto out_err1;
 
@@ -246,7 +243,7 @@ struct ttm_base_object *
 ttm_base_object_noref_lookup(struct ttm_object_file *tfile, uint32_t key)
 {
 	struct vmwgfx_hash_item *hash;
-	struct vmwgfx_open_hash *ht = &tfile->ref_hash[TTM_REF_USAGE];
+	struct vmwgfx_open_hash *ht = &tfile->ref_hash;
 	int ret;
 
 	rcu_read_lock();
@@ -266,7 +263,7 @@ struct ttm_base_object *ttm_base_object_lookup(struct ttm_object_file *tfile,
 {
 	struct ttm_base_object *base = NULL;
 	struct vmwgfx_hash_item *hash;
-	struct vmwgfx_open_hash *ht = &tfile->ref_hash[TTM_REF_USAGE];
+	struct vmwgfx_open_hash *ht = &tfile->ref_hash;
 	int ret;
 
 	rcu_read_lock();
@@ -297,57 +294,12 @@ ttm_base_object_lookup_for_ref(struct ttm_object_device *tdev, uint32_t key)
 	return base;
 }
 
-/**
- * ttm_ref_object_exists - Check whether a caller has a valid ref object
- * (has opened) a base object.
- *
- * @tfile: Pointer to a struct ttm_object_file identifying the caller.
- * @base: Pointer to a struct base object.
- *
- * Checks wether the caller identified by @tfile has put a valid USAGE
- * reference object on the base object identified by @base.
- */
-bool ttm_ref_object_exists(struct ttm_object_file *tfile,
-			   struct ttm_base_object *base)
-{
-	struct vmwgfx_open_hash *ht = &tfile->ref_hash[TTM_REF_USAGE];
-	struct vmwgfx_hash_item *hash;
-	struct ttm_ref_object *ref;
-
-	rcu_read_lock();
-	if (unlikely(vmwgfx_ht_find_item_rcu(ht, base->handle, &hash) != 0))
-		goto out_false;
-
-	/*
-	 * Verify that the ref object is really pointing to our base object.
-	 * Our base object could actually be dead, and the ref object pointing
-	 * to another base object with the same handle.
-	 */
-	ref = drm_hash_entry(hash, struct ttm_ref_object, hash);
-	if (unlikely(base != ref->obj))
-		goto out_false;
-
-	/*
-	 * Verify that the ref->obj pointer was actually valid!
-	 */
-	rmb();
-	if (unlikely(kref_read(&ref->kref) == 0))
-		goto out_false;
-
-	rcu_read_unlock();
-	return true;
-
- out_false:
-	rcu_read_unlock();
-	return false;
-}
-
 int ttm_ref_object_add(struct ttm_object_file *tfile,
 		       struct ttm_base_object *base,
-		       enum ttm_ref_type ref_type, bool *existed,
+		       bool *existed,
 		       bool require_existed)
 {
-	struct vmwgfx_open_hash *ht = &tfile->ref_hash[ref_type];
+	struct vmwgfx_open_hash *ht = &tfile->ref_hash;
 	struct ttm_ref_object *ref;
 	struct vmwgfx_hash_item *hash;
 	int ret = -EINVAL;
@@ -382,7 +334,6 @@ int ttm_ref_object_add(struct ttm_object_file *tfile,
 		ref->hash.key = base->handle;
 		ref->obj = base;
 		ref->tfile = tfile;
-		ref->ref_type = ref_type;
 		kref_init(&ref->kref);
 
 		spin_lock(&tfile->lock);
@@ -411,27 +362,23 @@ ttm_ref_object_release(struct kref *kref)
 {
 	struct ttm_ref_object *ref =
 	    container_of(kref, struct ttm_ref_object, kref);
-	struct ttm_base_object *base = ref->obj;
 	struct ttm_object_file *tfile = ref->tfile;
 	struct vmwgfx_open_hash *ht;
 
-	ht = &tfile->ref_hash[ref->ref_type];
+	ht = &tfile->ref_hash;
 	(void)vmwgfx_ht_remove_item_rcu(ht, &ref->hash);
 	list_del(&ref->head);
 	spin_unlock(&tfile->lock);
 
-	if (ref->ref_type != TTM_REF_USAGE && base->ref_obj_release)
-		base->ref_obj_release(base, ref->ref_type);
-
 	ttm_base_object_unref(&ref->obj);
 	kfree_rcu(ref, rcu_head);
 	spin_lock(&tfile->lock);
 }
 
 int ttm_ref_object_base_unref(struct ttm_object_file *tfile,
-			      unsigned long key, enum ttm_ref_type ref_type)
+			      unsigned long key)
 {
-	struct vmwgfx_open_hash *ht = &tfile->ref_hash[ref_type];
+	struct vmwgfx_open_hash *ht = &tfile->ref_hash;
 	struct ttm_ref_object *ref;
 	struct vmwgfx_hash_item *hash;
 	int ret;
@@ -452,7 +399,6 @@ void ttm_object_file_release(struct ttm_object_file **p_tfile)
 {
 	struct ttm_ref_object *ref;
 	struct list_head *list;
-	unsigned int i;
 	struct ttm_object_file *tfile = *p_tfile;
 
 	*p_tfile = NULL;
@@ -470,8 +416,7 @@ void ttm_object_file_release(struct ttm_object_file **p_tfile)
 	}
 
 	spin_unlock(&tfile->lock);
-	for (i = 0; i < TTM_REF_NUM; ++i)
-		vmwgfx_ht_remove(&tfile->ref_hash[i]);
+	vmwgfx_ht_remove(&tfile->ref_hash);
 
 	ttm_object_file_unref(&tfile);
 }
@@ -480,8 +425,6 @@ struct ttm_object_file *ttm_object_file_init(struct ttm_object_device *tdev,
 					     unsigned int hash_order)
 {
 	struct ttm_object_file *tfile = kmalloc(sizeof(*tfile), GFP_KERNEL);
-	unsigned int i;
-	unsigned int j = 0;
 	int ret;
 
 	if (unlikely(tfile == NULL))
@@ -492,18 +435,13 @@ struct ttm_object_file *ttm_object_file_init(struct ttm_object_device *tdev,
 	kref_init(&tfile->refcount);
 	INIT_LIST_HEAD(&tfile->ref_list);
 
-	for (i = 0; i < TTM_REF_NUM; ++i) {
-		ret = vmwgfx_ht_create(&tfile->ref_hash[i], hash_order);
-		if (ret) {
-			j = i;
-			goto out_err;
-		}
-	}
+	ret = vmwgfx_ht_create(&tfile->ref_hash, hash_order);
+	if (ret)
+		goto out_err;
 
 	return tfile;
 out_err:
-	for (i = 0; i < j; ++i)
-		vmwgfx_ht_remove(&tfile->ref_hash[i]);
+	vmwgfx_ht_remove(&tfile->ref_hash);
 
 	kfree(tfile);
 
@@ -526,7 +464,15 @@ ttm_object_device_init(unsigned int hash_order,
 	if (ret != 0)
 		goto out_no_object_hash;
 
-	idr_init_base(&tdev->idr, 1);
+	/*
+	 * Our base is at VMWGFX_NUM_MOB + 1 because we want to create
+	 * a seperate namespace for GEM handles (which are
+	 * 1..VMWGFX_NUM_MOB) and the surface handles. Some ioctl's
+	 * can take either handle as an argument so we want to
+	 * easily be able to tell whether the handle refers to a
+	 * GEM buffer or a surface.
+	 */
+	idr_init_base(&tdev->idr, VMWGFX_NUM_MOB + 1);
 	tdev->ops = *ops;
 	tdev->dmabuf_release = tdev->ops.release;
 	tdev->ops.release = ttm_prime_dmabuf_release;
@@ -647,7 +593,7 @@ int ttm_prime_fd_to_handle(struct ttm_object_file *tfile,
 	prime = (struct ttm_prime_object *) dma_buf->priv;
 	base = &prime->base;
 	*handle = base->handle;
-	ret = ttm_ref_object_add(tfile, base, TTM_REF_USAGE, NULL, false);
+	ret = ttm_ref_object_add(tfile, base, NULL, false);
 
 	dma_buf_put(dma_buf);
 
@@ -741,17 +687,14 @@ int ttm_prime_handle_to_fd(struct ttm_object_file *tfile,
  * @shareable: See ttm_base_object_init
  * @type: See ttm_base_object_init
  * @refcount_release: See ttm_base_object_init
- * @ref_obj_release: See ttm_base_object_init
  *
  * Initializes an object which is compatible with the drm_prime model
  * for data sharing between processes and devices.
  */
 int ttm_prime_object_init(struct ttm_object_file *tfile, size_t size,
 			  struct ttm_prime_object *prime, bool shareable,
 			  enum ttm_object_type type,
-			  void (*refcount_release) (struct ttm_base_object **),
-			  void (*ref_obj_release) (struct ttm_base_object *,
-						   enum ttm_ref_type ref_type))
+			  void (*refcount_release) (struct ttm_base_object **))
 {
 	mutex_init(&prime->mutex);
 	prime->size = PAGE_ALIGN(size);
@@ -760,6 +703,5 @@ int ttm_prime_object_init(struct ttm_object_file *tfile, size_t size,
 	prime->refcount_release = refcount_release;
 	return ttm_base_object_init(tfile, &prime->base, shareable,
 				    ttm_prime_type,
-				    ttm_prime_refcount_release,
-				    ref_obj_release);
+				    ttm_prime_refcount_release);
 }

drivers/gpu/drm/vmwgfx/ttm_object.h

@@ -44,28 +44,6 @@
 
 #include "vmwgfx_hashtab.h"
 
-/**
- * enum ttm_ref_type
- *
- * Describes what type of reference a ref object holds.
- *
- * TTM_REF_USAGE is a simple refcount on a base object.
- *
- * TTM_REF_SYNCCPU_READ is a SYNCCPU_READ reference on a
- * buffer object.
- *
- * TTM_REF_SYNCCPU_WRITE is a SYNCCPU_WRITE reference on a
- * buffer object.
- *
- */
-
-enum ttm_ref_type {
-	TTM_REF_USAGE,
-	TTM_REF_SYNCCPU_READ,
-	TTM_REF_SYNCCPU_WRITE,
-	TTM_REF_NUM
-};
-
 /**
  * enum ttm_object_type
  *
@@ -76,7 +54,6 @@ enum ttm_ref_type {
 
 enum ttm_object_type {
 	ttm_fence_type,
-	ttm_buffer_type,
 	ttm_lock_type,
 	ttm_prime_type,
 	ttm_driver_type0 = 256,
@@ -127,8 +104,6 @@ struct ttm_base_object {
 	struct ttm_object_file *tfile;
 	struct kref refcount;
 	void (*refcount_release) (struct ttm_base_object **base);
-	void (*ref_obj_release) (struct ttm_base_object *base,
-				 enum ttm_ref_type ref_type);
 	u32 handle;
 	enum ttm_object_type object_type;
 	u32 shareable;
@@ -177,11 +152,7 @@ extern int ttm_base_object_init(struct ttm_object_file *tfile,
 				bool shareable,
 				enum ttm_object_type type,
 				void (*refcount_release) (struct ttm_base_object
-							  **),
-				void (*ref_obj_release) (struct ttm_base_object
-							 *,
-							 enum ttm_ref_type
-							 ref_type));
+							  **));
 
 /**
  * ttm_base_object_lookup
@@ -245,12 +216,9 @@ extern void ttm_base_object_unref(struct ttm_base_object **p_base);
  */
 extern int ttm_ref_object_add(struct ttm_object_file *tfile,
 			      struct ttm_base_object *base,
-			      enum ttm_ref_type ref_type, bool *existed,
+			      bool *existed,
 			      bool require_existed);
 
-extern bool ttm_ref_object_exists(struct ttm_object_file *tfile,
-				  struct ttm_base_object *base);
-
 /**
  * ttm_ref_object_base_unref
  *
@@ -263,8 +231,7 @@ extern bool ttm_ref_object_exists(struct ttm_object_file *tfile,
  * will be unreferenced.
  */
 extern int ttm_ref_object_base_unref(struct ttm_object_file *tfile,
-				     unsigned long key,
-				     enum ttm_ref_type ref_type);
+				     unsigned long key);
 
 /**
  * ttm_object_file_init - initialize a struct ttm_object file
@@ -328,10 +295,7 @@ extern int ttm_prime_object_init(struct ttm_object_file *tfile,
 				 bool shareable,
 				 enum ttm_object_type type,
 				 void (*refcount_release)
-				 (struct ttm_base_object **),
-				 void (*ref_obj_release)
-				 (struct ttm_base_object *,
-				  enum ttm_ref_type ref_type));
+				 (struct ttm_base_object **));
 
 static inline enum ttm_object_type
 ttm_base_object_type(struct ttm_base_object *base)