Re: [Qemu-devel] [PATCH] compile x86_64 on i386

[Anthony Liguori]

Glauber Costa wrote:
> On Wed, Nov 5, 2008 at 5:13 PM, Anthony Liguori <address@hidden> wrote:
>   
> > Glauber Costa wrote:
> >     
> > > This patch allows qemu-system-x86_64 to be compiled on a i386 host.
> > >
> > >       
> > For this to properly work, you need to fix the FIXMEs in target-i386/kvm.c
> > that are around lm_capable_check.  Basically, if you're on a 32-bit kernel,
> > but a 64-bit capable processor, you need to mask long mode from the guest or
> > it may try to use it.
> >     
>
> Yes, but 32-bit kernels work fine (since they not even try)
> So they are orthogonal.
>   

Well, I don't buy your argument, but we have the same problem with 
qemu-system-i386 anyway so I guess your patch makes things no worse.

I've committed something slightly different that I hope will extend more 
easily.  Thanks.

Regards,

Anthony Liguori

> > Regards,
> >
> > Anthony Liguori
> >
> >     
> > > ---
> > >  configure |   17 ++++++++++-------
> > >  1 files changed, 10 insertions(+), 7 deletions(-)
> > >
> > > diff --git a/configure b/configure
> > > index 067c3c5..65f0c74 100755
> > > --- a/configure
> > > +++ b/configure
> > > @@ -1447,13 +1447,16 @@ interp_prefix1=`echo "$interp_prefix" | sed
> > > "s/%M/$target_cpu/g"`
> > >  echo "#define CONFIG_QEMU_PREFIX \"$interp_prefix1\"" >> $config_h
> > >  gdb_xml_files=""
> > >  -# FIXME allow i386 to build on x86_64 and vice versa
> > > -if test "$kvm" = "yes" -a "$target_cpu" != "$cpu" ; then
> > > -  kvm="no"
> > > -fi
> > > -# Disable KVM for linux-user
> > > -if test "$kvm" = "yes" -a "$target_softmmu" = "no" ; then
> > > -  kvm="no"
> > > +if test "$kvm" = "yes";
> > > +then
> > > +  # Disable KVM for linux-user
> > > +  if test "$target_softmmu" = "no";
> > > +  then
> > > +     kvm="no"
> > > +  elif test "$target_cpu" != "$cpu" && test ! "$cpu" = "i386" -a
> > >  "$target_cpu" = "x86_64" ;
> > > +  then
> > > +        kvm="no"
> > > +  fi
> > >  fi
> > >   case "$target_cpu" in
> > >
> > >       
> >
> >
> >     
>
>
>
>