[PATCH v3 20/23] drm/qxl: add mode/framebuffer check functions

Gerd Hoffmann
2019-01-18T12:20:51Z

Add a helper functions to check video modes. Also add a helper to check
framebuffer buffer objects, using the former for consistency. That way
we should not fail in qxl_primary_atomic_check() because video modes
which are too big will not be added to the mode list in the first place.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
drivers/gpu/drm/qxl/qxl_display.c | 44 +++++++++++++++++++++++----------------
1 file changed, 26 insertions(+), 18 deletions(-)

diff --git a/drivers/gpu/drm/qxl/qxl_display.c b/drivers/gpu/drm/qxl/qxl_display.c
index 9c751f01e3..fed2ea018d 100644
--- a/drivers/gpu/drm/qxl/qxl_display.c
+++ b/drivers/gpu/drm/qxl/qxl_display.c
@@ -190,6 +190,28 @@ void qxl_display_read_client_monitors_config(struct qxl_device *qdev)
}
}

+static int qxl_check_mode(struct qxl_device *qdev,
+ unsigned int width,
+ unsigned int height)
+{
+ unsigned int stride;
+ unsigned int size;
+
+ if (check_mul_overflow(width, 4u, &stride))
+ return -EINVAL;
+ if (check_mul_overflow(stride, height, &size))
+ return -EINVAL;
+ if (size > qdev->vram_size)
+ return -ENOMEM;
+ return 0;
+}
+
+static int qxl_check_framebuffer(struct qxl_device *qdev,
+ struct qxl_bo *bo)
+{
+ return qxl_check_mode(qdev, bo->surf.width, bo->surf.height);
+}
+
static int qxl_add_monitors_config_modes(struct drm_connector *connector,
unsigned *pwidth,
unsigned *pheight)
@@ -469,12 +491,7 @@ static int qxl_primary_atomic_check(struct drm_plane *plane,

bo = gem_to_qxl_bo(state->fb->obj[0]);

- if (bo->surf.stride * bo->surf.height > qdev->vram_size) {
- DRM_ERROR("Mode doesn't fit in vram size (vgamem)");
- return -EINVAL;
- }
-
- return 0;
+ return qxl_check_framebuffer(qdev, bo);
}

static int qxl_primary_apply_cursor(struct drm_plane *plane)
@@ -990,20 +1007,11 @@ static enum drm_mode_status qxl_conn_mode_valid(struct drm_connector *connector,
{
struct drm_device *ddev = connector->dev;
struct qxl_device *qdev = ddev->dev_private;
- int i;

- /* TODO: is this called for user defined modes? (xrandr --add-mode)
- * TODO: check that the mode fits in the framebuffer */
+ if (qxl_check_mode(qdev, mode->hdisplay, mode->vdisplay) != 0)
+ return MODE_BAD;

- if (qdev->monitors_config_width == mode->hdisplay &&
- qdev->monitors_config_height == mode->vdisplay)
- return MODE_OK;
-
- for (i = 0; i < ARRAY_SIZE(common_modes); i++) {
- if (common_modes[i].w == mode->hdisplay && common_modes[i].h == mode->vdisplay)
- return MODE_OK;
- }
- return MODE_BAD;
+ return MODE_OK;
}

static struct drm_encoder *qxl_best_encoder(struct drm_connector *connector)
--
2.9.3