[Qemu-devel] [PATCH] vga: print friendly error message in case multiple vga devices are added

[Gerd Hoffmann <kraxel@redhat.com>]

... to a virtual machine.  Without that we fail a ramblock register
sanity check, leading to a abort(), which isn't exactly user friendly.

https://bugzilla.redhat.com/show_bug.cgi?id=1206037
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
 hw/display/vga.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/hw/display/vga.c b/hw/display/vga.c
index 72181330b8..328b6413ad 100644
--- a/hw/display/vga.c
+++ b/hw/display/vga.c
@@ -2184,6 +2184,14 @@ void vga_common_init(VGACommonState *s, Object *obj, bool global_vmstate)
     }
     s->vbe_size_mask = s->vbe_size - 1;
 
+    if (global_vmstate) {
+        static int have_vga;
+        if (have_vga) {
+            error_report("only one vga device is supported");
+            exit(1);
+        }
+        have_vga = true;
+    }
     s->is_vbe_vmstate = 1;
     memory_region_init_ram_nomigrate(&s->vram, obj, "vga.vram", s->vram_size,
                            &error_fatal);
-- 
2.9.3