Re: [Qemu-devel] [PATCH] vmware_vga: Redraw only visible area

[Michael Tokarev <mjt@tls.msk.ru>]

On 17.08.2012 06:55, Marek Vasut wrote:
> Disallow negative value boundaries of the redraw rectangle.
> This fixes a segfault when using -vga vmware.
> 
> Signed-off-by: Marek Vasut <marex@denx.de>
> ---
>  hw/vmware_vga.c |    4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> NOTE: I tested this by emulating some recent version of ubuntu. The rect->x
>       value was set to -65 for some reason at one point, which caused the
>       kvm to crash. Trimming the rectangle fixed the issue.
> 
> diff --git a/hw/vmware_vga.c b/hw/vmware_vga.c
> index f5e4f44..62e5887 100644
> --- a/hw/vmware_vga.c
> +++ b/hw/vmware_vga.c
> @@ -337,8 +337,8 @@ static inline void vmsvga_update_rect_delayed(struct vmsvga_state_s *s,
>  {
>      struct vmsvga_rect_s *rect = &s->redraw_fifo[s->redraw_fifo_last ++];
>      s->redraw_fifo_last &= REDRAW_FIFO_LEN - 1;
> -    rect->x = x;
> -    rect->y = y;
> +    rect->x = (x < 0) ? 0 : x;
> +    rect->y = (y < 0) ? 0 : y;
>      rect->w = w;
>      rect->h = h;
>  }


Is it the same as https://bugs.launchpad.net/bugs/918791 ?
At least it appears to be the same theme...  But there,
the patch (https://launchpadlibrarian.net/94916786/qemu-vmware.debdiff)
also updates width/height.  My comment:
https://bugs.launchpad.net/ubuntu/+source/qemu-kvm/+bug/918791/comments/21

"So indeed, some (upstream) verification is needed here -- where these
negative values are coming from, whenever it is EVER okay to have them,
what to do with these, and where to check (I guess the check should be
done somewhere in the upper layer)."

Especially the last part about the layer.

Thanks,

/mjt