Re: [Qemu-devel] [PATCH v2] cirrus_vga: adding sanity check for vram size

["Andreas Färber" <afaerber@suse.de>]

Am 09.05.2014 13:04, schrieb arei.gonglei@huawei.com:
> From: Gonglei <arei.gonglei@huawei.com>
> 
> 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>
> ---
> v2: fix checkpatch fails.
>   "WARNING: suspect code indent for conditional statements (5, 9)"
>   maybe not a real warning.
> 
>  hw/display/cirrus_vga.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/hw/display/cirrus_vga.c b/hw/display/cirrus_vga.c
> index d1afc76..399a2ef 100644
> --- a/hw/display/cirrus_vga.c
> +++ b/hw/display/cirrus_vga.c
> @@ -2959,6 +2959,14 @@ 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) {

Apart from the logic bug mjt already pointed out, I note that this check
is in the PCI initfn. Should the same restriction also apply for the ISA
version of the device?

> +         error_report("Invalid cirrus_vga ram size '%u'\n",
> +                      s->vga.vram_size_mb);

Thanks for using our new error_report(). It does not require a trailing
\n though.

Regards,
Andreas

> +         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),

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