cirrus_vga: adding sanity check for vram size

when configure a invalid vram size for cirrus card, such as less
2 MB, which will crash qemu. Follow the real hardware, the cirrus
card has 4 MB video memory. Also for backward compatibility, accept
8 MB and 16 MB vram size.

Signed-off-by: Gonglei <arei.gonglei@huawei.com>
Reviewed-by: Andreas Färber <afaerber@suse.de>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

diff --git a/hw/display/cirrus_vga.c b/hw/display/cirrus_vga.c
index 6fbe39d5d40f90f4b17085f9107e7136fd755383..52d039e9bc0f1cae294b65adf0670522ed699cb8 100644 (file)
--- a/hw/display/cirrus_vga.c
+++ b/hw/display/cirrus_vga.c
@@ -2911,6 +2911,14 @@ static void isa_cirrus_vga_realizefn(DeviceState *dev, Error **errp)
     ISACirrusVGAState *d = ISA_CIRRUS_VGA(dev);
     VGACommonState *s = &d->cirrus_vga.vga;
 
+    /* follow real hardware, cirrus card emulated has 4 MB video memory.
+       Also accept 8 MB/16 MB for backward compatibility. */
+    if (s->vram_size_mb != 4 && s->vram_size_mb != 8 &&
+        s->vram_size_mb != 16) {
+        error_setg(errp, "Invalid cirrus_vga ram size '%u'",
+                   s->vram_size_mb);
+        return;
+    }
     vga_common_init(s, OBJECT(dev), true);
     cirrus_init_common(&d->cirrus_vga, OBJECT(dev), CIRRUS_ID_CLGD5430, 0,
                        isa_address_space(isadev),
@@ -2957,6 +2965,14 @@ static int pci_cirrus_vga_initfn(PCIDevice *dev)
      PCIDeviceClass *pc = PCI_DEVICE_GET_CLASS(dev);
      int16_t device_id = pc->device_id;
 
+     /* follow real hardware, cirrus card emulated has 4 MB video memory.
+       Also accept 8 MB/16 MB for backward compatibility. */
+     if (s->vga.vram_size_mb != 4 && s->vga.vram_size_mb != 8 &&
+         s->vga.vram_size_mb != 16) {
+         error_report("Invalid cirrus_vga ram size '%u'",
+                      s->vga.vram_size_mb);
+         return -1;
+     }
      /* setup VGA */
      vga_common_init(&s->vga, OBJECT(dev), true);
      cirrus_init_common(s, OBJECT(dev), device_id, 1, pci_address_space(dev),