drm/vmwgfx: Stop using surface dma commands on most configurations

Initial version of guest backed objects in the host had some performance
issues that made using surface-dma's instead of direct copies faster.
Surface dma's force a migration to vram which at best is slow and at
worst is impossible (e.g. on svga3 where there's not enough vram
to migrate fb's to it).

Slowly migrate away from surface dma's to direct copies by limiting
their usage to systems with more than 32MB of vram.
Signed-off-by: Zack Rusin <zackr@vmware.com>
Reviewed-by: Maaz Mombasawala <mombasawalam@vmware.com>
Reviewed-by: Martin Krastev <krastevm@vmware.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220302152426.885214-9-zack@kde.org

drivers/gpu/drm/vmwgfx/vmwgfx_stdu.c

@@ -138,6 +138,11 @@ static void vmw_stdu_destroy(struct vmw_screen_target_display_unit *stdu);
  * Screen Target Display Unit CRTC Functions
  *****************************************************************************/
 
+static bool vmw_stdu_use_cpu_blit(const struct vmw_private *vmw)
+{
+	return !(vmw->capabilities & SVGA_CAP_3D) || vmw->vram_size < (32 * 1024 * 1024);
+}
+
 
 /**
  * vmw_stdu_crtc_destroy - cleans up the STDU
@@ -689,7 +694,7 @@ int vmw_kms_stdu_dma(struct vmw_private *dev_priv,
 		container_of(vfb, struct vmw_framebuffer_bo, base)->buffer;
 	struct vmw_stdu_dirty ddirty;
 	int ret;
-	bool cpu_blit = !(dev_priv->capabilities & SVGA_CAP_3D);
+	bool cpu_blit = vmw_stdu_use_cpu_blit(dev_priv);
 	DECLARE_VAL_CONTEXT(val_ctx, NULL, 0);
 
 	/*
@@ -1164,7 +1169,7 @@ vmw_stdu_primary_plane_prepare_fb(struct drm_plane *plane,
 	 * so cache these mappings
 	 */
 	if (vps->content_fb_type == SEPARATE_BO &&
-	    !(dev_priv->capabilities & SVGA_CAP_3D))
+	    vmw_stdu_use_cpu_blit(dev_priv))
 		vps->cpp = new_fb->pitches[0] / new_fb->width;
 
 	return 0;
@@ -1368,7 +1373,7 @@ static int vmw_stdu_plane_update_bo(struct vmw_private *dev_priv,
 	bo_update.base.vfb = vfb;
 	bo_update.base.out_fence = out_fence;
 	bo_update.base.mutex = NULL;
-	bo_update.base.cpu_blit = !(dev_priv->capabilities & SVGA_CAP_3D);
+	bo_update.base.cpu_blit = vmw_stdu_use_cpu_blit(dev_priv);
 	bo_update.base.intr = false;
 
 	/*