Patch "drm/vmwgfx: Filter modes which exceed graphics memory" has been added to the 6.6-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    drm/vmwgfx: Filter modes which exceed graphics memory

to the 6.6-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     drm-vmwgfx-filter-modes-which-exceed-graphics-memory.patch
and it can be found in the queue-6.6 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit db11500ff2d4a5d581032f22a3146877e45a1076
Author: Ian Forbes <ian.forbes@xxxxxxxxxxxx>
Date:   Tue May 21 13:47:17 2024 -0500

    drm/vmwgfx: Filter modes which exceed graphics memory
    
    [ Upstream commit 426826933109093503e7ef15d49348fc5ab505fe ]
    
    SVGA requires individual surfaces to fit within graphics memory
    (max_mob_pages) which means that modes with a final buffer size that would
    exceed graphics memory must be pruned otherwise creation will fail.
    
    Additionally llvmpipe requires its buffer height and width to be a multiple
    of its tile size which is 64. As a result we have to anticipate that
    llvmpipe will round up the mode size passed to it by the compositor when
    it creates buffers and filter modes where this rounding exceeds graphics
    memory.
    
    This fixes an issue where VMs with low graphics memory (< 64MiB) configured
    with high resolution mode boot to a black screen because surface creation
    fails.
    
    Fixes: d947d1b71deb ("drm/vmwgfx: Add and connect connector helper function")
    Signed-off-by: Ian Forbes <ian.forbes@xxxxxxxxxxxx>
    Signed-off-by: Zack Rusin <zack.rusin@xxxxxxxxxxxx>
    Link: https://patchwork.freedesktop.org/patch/msgid/20240521184720.767-2-ian.forbes@xxxxxxxxxxxx
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_stdu.c b/drivers/gpu/drm/vmwgfx/vmwgfx_stdu.c
index 12d623ee59c25..4ccab07faff08 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_stdu.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_stdu.c
@@ -41,7 +41,14 @@
 #define vmw_connector_to_stdu(x) \
 	container_of(x, struct vmw_screen_target_display_unit, base.connector)
 
-
+/*
+ * Some renderers such as llvmpipe will align the width and height of their
+ * buffers to match their tile size. We need to keep this in mind when exposing
+ * modes to userspace so that this possible over-allocation will not exceed
+ * graphics memory. 64x64 pixels seems to be a reasonable upper bound for the
+ * tile size of current renderers.
+ */
+#define GPU_TILE_SIZE 64
 
 enum stdu_content_type {
 	SAME_AS_DISPLAY = 0,
@@ -825,7 +832,41 @@ static void vmw_stdu_connector_destroy(struct drm_connector *connector)
 	vmw_stdu_destroy(vmw_connector_to_stdu(connector));
 }
 
+static enum drm_mode_status
+vmw_stdu_connector_mode_valid(struct drm_connector *connector,
+			      struct drm_display_mode *mode)
+{
+	enum drm_mode_status ret;
+	struct drm_device *dev = connector->dev;
+	struct vmw_private *dev_priv = vmw_priv(dev);
+	u64 assumed_cpp = dev_priv->assume_16bpp ? 2 : 4;
+	/* Align width and height to account for GPU tile over-alignment */
+	u64 required_mem = ALIGN(mode->hdisplay, GPU_TILE_SIZE) *
+			   ALIGN(mode->vdisplay, GPU_TILE_SIZE) *
+			   assumed_cpp;
+	required_mem = ALIGN(required_mem, PAGE_SIZE);
+
+	ret = drm_mode_validate_size(mode, dev_priv->stdu_max_width,
+				     dev_priv->stdu_max_height);
+	if (ret != MODE_OK)
+		return ret;
 
+	ret = drm_mode_validate_size(mode, dev_priv->texture_max_width,
+				     dev_priv->texture_max_height);
+	if (ret != MODE_OK)
+		return ret;
+
+	if (required_mem > dev_priv->max_primary_mem)
+		return MODE_MEM;
+
+	if (required_mem > dev_priv->max_mob_pages * PAGE_SIZE)
+		return MODE_MEM;
+
+	if (required_mem > dev_priv->max_mob_size)
+		return MODE_MEM;
+
+	return MODE_OK;
+}
 
 static const struct drm_connector_funcs vmw_stdu_connector_funcs = {
 	.dpms = vmw_du_connector_dpms,
@@ -841,7 +882,7 @@ static const struct drm_connector_funcs vmw_stdu_connector_funcs = {
 static const struct
 drm_connector_helper_funcs vmw_stdu_connector_helper_funcs = {
 	.get_modes = vmw_connector_get_modes,
-	.mode_valid = vmw_connector_mode_valid
+	.mode_valid = vmw_stdu_connector_mode_valid
 };