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

[Marek Vasut]

> Dear Michael Tokarev,

Bump? Did this lead anywhere? Do you need updated patch?

> > 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 <address@hidden>
> > > ---
> > > 
> > >  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/2
> > 1
> 
> Looks to be the same ... though my patch tries to squash the issue as early
> as possible.
> 
> You're right that x and y might overflow to the other side too. Also,
> you're right about w and h.
> 
> Shall I send updated patch?
> 
> > "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.
> 
> Where's the upper layer though, isn't that what's pouring out of the
> virtual machine itself?
> 
> > Thanks,
> 
> Thank you for guidance !
> 
> > /mjt
> 
> Best regards,
> Marek Vasut

Best regards,
Marek Vasut