drm/vmwgfx: Don't cache framebuffer maps

Buffer objects need to be either pinned or reserved while a map is active,
that's not the case here, so avoid caching the framebuffer map.
This will cause increasing mapping activity mainly when we don't do
page flipping.

This fixes occasional garbage filled screens when the framebuffer has been
evicted after the map.

Since in-kernel mapping of whole buffer objects is error-prone on 32-bit
architectures and also quite inefficient, we will revisit this later.
Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: Sinclair Yeh <syeh@vmware.com>
Cc: <stable@vger.kernel.org>

drivers/gpu/drm/vmwgfx/vmwgfx_kms.c

@@ -697,7 +697,6 @@ vmw_du_plane_duplicate_state(struct drm_plane *plane)
 	vps->pinned = 0;
 
 	/* Mapping is managed by prepare_fb/cleanup_fb */
-	memset(&vps->guest_map, 0, sizeof(vps->guest_map));
 	memset(&vps->host_map, 0, sizeof(vps->host_map));
 	vps->cpp = 0;
 
@@ -760,11 +759,6 @@ vmw_du_plane_destroy_state(struct drm_plane *plane,
 
 
 	/* Should have been freed by cleanup_fb */
-	if (vps->guest_map.virtual) {
-		DRM_ERROR("Guest mapping not freed\n");
-		ttm_bo_kunmap(&vps->guest_map);
-	}
-
 	if (vps->host_map.virtual) {
 		DRM_ERROR("Host mapping not freed\n");
 		ttm_bo_kunmap(&vps->host_map);

drivers/gpu/drm/vmwgfx/vmwgfx_kms.h

@@ -175,7 +175,7 @@ struct vmw_plane_state {
 	int pinned;
 
 	/* For CPU Blit */
-	struct ttm_bo_kmap_obj host_map, guest_map;
+	struct ttm_bo_kmap_obj host_map;
 	unsigned int cpp;
 };
 

drivers/gpu/drm/vmwgfx/vmwgfx_stdu.c

@@ -114,7 +114,7 @@ struct vmw_screen_target_display_unit {
 	bool defined;
 
 	/* For CPU Blit */
-	struct ttm_bo_kmap_obj host_map, guest_map;
+	struct ttm_bo_kmap_obj host_map;
 	unsigned int cpp;
 };
 
@@ -695,7 +695,8 @@ static void vmw_stdu_dmabuf_cpu_commit(struct vmw_kms_dirty *dirty)
 	s32 src_pitch, dst_pitch;
 	u8 *src, *dst;
 	bool not_used;
-
+	struct ttm_bo_kmap_obj guest_map;
+	int ret;
 
 	if (!dirty->num_hits)
 		return;
@@ -706,6 +707,13 @@ static void vmw_stdu_dmabuf_cpu_commit(struct vmw_kms_dirty *dirty)
 	if (width == 0 || height == 0)
 		return;
 
+	ret = ttm_bo_kmap(&ddirty->buf->base, 0, ddirty->buf->base.num_pages,
+			  &guest_map);
+	if (ret) {
+		DRM_ERROR("Failed mapping framebuffer for blit: %d\n",
+			  ret);
+		goto out_cleanup;
+	}
 
 	/* Assume we are blitting from Host (display_srf) to Guest (dmabuf) */
 	src_pitch = stdu->display_srf->base_size.width * stdu->cpp;
@@ -713,7 +721,7 @@ static void vmw_stdu_dmabuf_cpu_commit(struct vmw_kms_dirty *dirty)
 	src += ddirty->top * src_pitch + ddirty->left * stdu->cpp;
 
 	dst_pitch = ddirty->pitch;
-	dst = ttm_kmap_obj_virtual(&stdu->guest_map, &not_used);
+	dst = ttm_kmap_obj_virtual(&guest_map, &not_used);
 	dst += ddirty->fb_top * dst_pitch + ddirty->fb_left * stdu->cpp;
 
 
@@ -772,6 +780,7 @@ static void vmw_stdu_dmabuf_cpu_commit(struct vmw_kms_dirty *dirty)
 		vmw_fifo_commit(dev_priv, sizeof(*cmd));
 	}
 
+	ttm_bo_kunmap(&guest_map);
 out_cleanup:
 	ddirty->left = ddirty->top = ddirty->fb_left = ddirty->fb_top = S32_MAX;
 	ddirty->right = ddirty->bottom = S32_MIN;
@@ -1109,9 +1118,6 @@ vmw_stdu_primary_plane_cleanup_fb(struct drm_plane *plane,
 {
 	struct vmw_plane_state *vps = vmw_plane_state_to_vps(old_state);
 
-	if (vps->guest_map.virtual)
-		ttm_bo_kunmap(&vps->guest_map);
-
 	if (vps->host_map.virtual)
 		ttm_bo_kunmap(&vps->host_map);
 
@@ -1277,33 +1283,11 @@ vmw_stdu_primary_plane_prepare_fb(struct drm_plane *plane,
 	 */
 	if (vps->content_fb_type == SEPARATE_DMA &&
 	    !(dev_priv->capabilities & SVGA_CAP_3D)) {
-
-		struct vmw_framebuffer_dmabuf *new_vfbd;
-
-		new_vfbd = vmw_framebuffer_to_vfbd(new_fb);
-
-		ret = ttm_bo_reserve(&new_vfbd->buffer->base, false, false,
-				     NULL);
-		if (ret)
-			goto out_srf_unpin;
-
-		ret = ttm_bo_kmap(&new_vfbd->buffer->base, 0,
-				  new_vfbd->buffer->base.num_pages,
-				  &vps->guest_map);
-
-		ttm_bo_unreserve(&new_vfbd->buffer->base);
-
-		if (ret) {
-			DRM_ERROR("Failed to map content buffer to CPU\n");
-			goto out_srf_unpin;
-		}
-
 		ret = ttm_bo_kmap(&vps->surf->res.backup->base, 0,
 				  vps->surf->res.backup->base.num_pages,
 				  &vps->host_map);
 		if (ret) {
 			DRM_ERROR("Failed to map display buffer to CPU\n");
-			ttm_bo_kunmap(&vps->guest_map);
 			goto out_srf_unpin;
 		}
 
@@ -1350,7 +1334,6 @@ vmw_stdu_primary_plane_atomic_update(struct drm_plane *plane,
 	stdu->display_srf = vps->surf;
 	stdu->content_fb_type = vps->content_fb_type;
 	stdu->cpp = vps->cpp;
-	memcpy(&stdu->guest_map, &vps->guest_map, sizeof(vps->guest_map));
 	memcpy(&stdu->host_map, &vps->host_map, sizeof(vps->host_map));
 
 	if (!stdu->defined)