Re: [PATCH RESEND] KVM: when entering real mode align segment base to 16 bytes

[Avi Kivity <avi@redhat.com>]

On 12/27/2010 04:58 PM, Gleb Natapov wrote:
> On Mon, Dec 27, 2010 at 04:55:08PM +0200, Avi Kivity wrote:
> >  On 12/27/2010 04:37 PM, Gleb Natapov wrote:
> >  >>   What's the scenario here?  And what segment is involved?  if it's fs
> >  >>   or gs, or maybe ss, I can see it working out, but hardly otherwise.
> >  >>
> >  >The scenario is older Seabios that lefts DS segment unaligned during
> >  >switch to real mode in int1587 function (copy extended memory).
> >  >
> >
> >  Did it not use %ds then?
> >
> It restores %ds before first use. There can be other guests of course
> that try to use %ds in protected mode. We can distinguish one from the
> other.

Okay.  Please add a printk_once() if we lose some bits here, so we know 
something bad happened.

In theory we should do this for the other cases too, but they have been 
there long enough.

-- 
error compiling committee.c: too many arguments to function