ui: Add dpy_gfx_check_format() to check backend shared surface support

This allows VGA to decide whether to use a shared surface based on
whether the UI backend supports the format or not. Backends that
don't provide the new callback fallback to native 32 bpp which
is equivalent to what was supported before.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

[ kraxel: fix console check, allow only 32 bpp as fallback ]

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

1 files changed, 25 insertions, 0 deletions

diff --git a/ui/console.c b/ui/console.c
index 258af5dfff..87574a73a8 100644
--- a/ui/console.c
+++ b/ui/console.c
@@ -1439,6 +1439,31 @@ void dpy_gfx_replace_surface(QemuConsole *con,
     qemu_free_displaysurface(old_surface);
 }
 
+bool dpy_gfx_check_format(QemuConsole *con,
+                          pixman_format_code_t format)
+{
+    DisplayChangeListener *dcl;
+    DisplayState *s = con->ds;
+
+    QLIST_FOREACH(dcl, &s->listeners, next) {
+        if (dcl->con && dcl->con != con) {
+            /* dcl bound to another console -> skip */
+            continue;
+        }
+        if (dcl->ops->dpy_gfx_check_format) {
+            if (!dcl->ops->dpy_gfx_check_format(dcl, format)) {
+                return false;
+            }
+        } else {
+            /* default is to whitelist native 32 bpp only */
+            if (format != qemu_default_pixman_format(32, true)) {
+                return false;
+            }
+        }
+    }
+    return true;
+}
+
 static void dpy_refresh(DisplayState *s)
 {
     DisplayChangeListener *dcl;