drm/vmwgfx: Add new keep_resv BO param

Adds a new BO param that keeps the reservation locked after creation.
This removes the need to re-reserve the BO after creation which is a
waste of cycles.

This also fixes a bug in vmw_prime_import_sg_table where the imported
reservation is unlocked twice.

Signed-off-by: Ian Forbes <ian.forbes@broadcom.com>
Fixes: b32233a ("drm/vmwgfx: Fix prime import/export")
Reviewed-by: Zack Rusin <zack.rusin@broadcom.com>
Signed-off-by: Zack Rusin <zack.rusin@broadcom.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250110185335.15301-1-ian.forbes@broadcom.com

Author: en4bz

drivers/gpu/drm/vmwgfx/vmwgfx_bo.c

@@ -442,7 +442,8 @@ static int vmw_bo_init(struct vmw_private *dev_priv,
 
 	if (params->pin)
 		ttm_bo_pin(&vmw_bo->tbo);
-	ttm_bo_unreserve(&vmw_bo->tbo);
+	if (!params->keep_resv)
+		ttm_bo_unreserve(&vmw_bo->tbo);
 
 	return 0;
 }

drivers/gpu/drm/vmwgfx/vmwgfx_bo.h

@@ -56,8 +56,9 @@ struct vmw_bo_params {
 	u32 domain;
 	u32 busy_domain;
 	enum ttm_bo_type bo_type;
-	size_t size;
 	bool pin;
+	bool keep_resv;
+	size_t size;
 	struct dma_resv *resv;
 	struct sg_table *sg;
 };

drivers/gpu/drm/vmwgfx/vmwgfx_drv.c

@@ -403,7 +403,8 @@ static int vmw_dummy_query_bo_create(struct vmw_private *dev_priv)
 		.busy_domain = VMW_BO_DOMAIN_SYS,
 		.bo_type = ttm_bo_type_kernel,
 		.size = PAGE_SIZE,
-		.pin = true
+		.pin = true,
+		.keep_resv = true,
 	};
 
 	/*
@@ -415,10 +416,6 @@ static int vmw_dummy_query_bo_create(struct vmw_private *dev_priv)
 	if (unlikely(ret != 0))
 		return ret;
 
-	ret = ttm_bo_reserve(&vbo->tbo, false, true, NULL);
-	BUG_ON(ret != 0);
-	vmw_bo_pin_reserved(vbo, true);
-
 	ret = ttm_bo_kmap(&vbo->tbo, 0, 1, &map);
 	if (likely(ret == 0)) {
 		result = ttm_kmap_obj_virtual(&map, &dummy);

drivers/gpu/drm/vmwgfx/vmwgfx_gem.c

@@ -206,6 +206,7 @@ struct drm_gem_object *vmw_prime_import_sg_table(struct drm_device *dev,
 		.bo_type = ttm_bo_type_sg,
 		.size = attach->dmabuf->size,
 		.pin = false,
+		.keep_resv = true,
 		.resv = attach->dmabuf->resv,
 		.sg = table,
 

drivers/gpu/drm/vmwgfx/vmwgfx_shader.c

@@ -896,7 +896,8 @@ int vmw_compat_shader_add(struct vmw_private *dev_priv,
 		.busy_domain = VMW_BO_DOMAIN_SYS,
 		.bo_type = ttm_bo_type_device,
 		.size = size,
-		.pin = true
+		.pin = true,
+		.keep_resv = true,
 	};
 
 	if (!vmw_shader_id_ok(user_key, shader_type))
@@ -906,10 +907,6 @@ int vmw_compat_shader_add(struct vmw_private *dev_priv,
 	if (unlikely(ret != 0))
 		goto out;
 
-	ret = ttm_bo_reserve(&buf->tbo, false, true, NULL);
-	if (unlikely(ret != 0))
-		goto no_reserve;
-
 	/* Map and copy shader bytecode. */
 	ret = ttm_bo_kmap(&buf->tbo, 0, PFN_UP(size), &map);
 	if (unlikely(ret != 0)) {

drivers/gpu/drm/vmwgfx/vmwgfx_ttm_buffer.c

@@ -572,15 +572,14 @@ int vmw_bo_create_and_populate(struct vmw_private *dev_priv,
 		.busy_domain = domain,
 		.bo_type = ttm_bo_type_kernel,
 		.size = bo_size,
-		.pin = true
+		.pin = true,
+		.keep_resv = true,
 	};
 
 	ret = vmw_bo_create(dev_priv, &bo_params, &vbo);
 	if (unlikely(ret != 0))
 		return ret;
 
-	ret = ttm_bo_reserve(&vbo->tbo, false, true, NULL);
-	BUG_ON(ret != 0);
 	ret = vmw_ttm_populate(vbo->tbo.bdev, vbo->tbo.ttm, &ctx);
 	if (likely(ret == 0)) {
 		struct vmw_ttm_tt *vmw_tt =