From mboxrd@z Thu Jan  1 00:00:00 1970
From: Daniel Vetter <daniel@ffwll.ch>
Subject: Re: [Spice-devel] [PATCH 1/3] drm/qxl: add mode/framebuffer check
	functions
Date: Wed, 16 Jan 2019 14:21:41 +0100
Message-ID: <20190116132141.GX10517__15061.6257837557$1547692516$gmane$org@phenom.ffwll.local>
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To: Gerd Hoffmann <kraxel@redhat.com>
Cc: David Airlie <airlied@linux.ie>, open list <linux-kernel@vger.kernel.org>, dri-devel@lists.freedesktop.org, "open list:DRM DRIVER FOR QXL VIRTUAL GPU" <virtualization@lists.linux-foundation.org>, Daniel Vetter <daniel@ffwll.ch>, Dave Airlie <airlied@redhat.com>, "open list:DRM DRIVER FOR QXL VIRTUAL GPU" <spice-devel@lists.freedesktop.org>, Frediano Ziglio <fziglio@redhat.com>
List-Id: virtualization@lists.linuxfoundation.org

On Wed, Jan 16, 2019 at 12:28:00PM +0100, Gerd Hoffmann wrote:
> > > +static int qxl_check_mode(struct qxl_device *qdev,
> > > +			  unsigned int width,
> > > +			  unsigned int height)
> > > +{
> > > +	if (width * height * 4 > qdev->vram_size)
> > 
> > Is someone checking for integer overflows already?
> 
> Need to have a look.  This is just ...

The addfb ioctl checks for integer overflows for you.
-Daniel

> 
> > > -	if (bo->surf.stride * bo->surf.height > qdev->vram_size) {
> > > -		DRM_ERROR("Mode doesn't fit in vram size (vgamem)");
> > > -		return -EINVAL;
> > > -	}
> 
> ... that check moved into the new function.
> 
> cheers,
>   Gerd
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch