Re: [Qemu-devel] Insta-segfault! i386-linux-user

[Thayne Harbaugh]

On Tue, 2007-09-18 at 15:53 +0200, Ronald wrote:
> Thayne Harbaugh schreef:
> > Has anyone seen an insta-segfault with i386-linux-user qemu?  I've
> > compiled qemu-0.9.0 as well as qemu-cvs (2007-09-18) with gcc-3.4 and
> > -fno-strict-aliasing on an amd64 and I get this:
> >
> > ./i386-linux-user/qemu-i386 --help
> > Segmentation fault
> >
> > >From GDB:
> >
> > Program received signal SIGSEGV, Segmentation fault.
> > 0x0000000000000000 in ?? ()
> > (gdb) bt
> > #0  0x0000000000000000 in ?? ()
> > #1  0x00000000600575ed in __libc_csu_init ()
> > #2  0x00002b826c660ade in __libc_start_main () from /lib/libc.so.6
> > #3  0x00000000600050e9 in _start ()

<SNIP>

> >   
> Yes, I had this problem too. U only compiled the program using the 
> 'user' parameters.

I only compiled the 'user' portion because that's all I want.

>  But to get the virtualisation going, you need to 
> compile at least one 'softmmu' (whatever that is). Doing that will 
> create the executable: qemu    (this is the executable you want :)   )

Err, no.  I don't want full virtualization.

> So I run Linux and I compile it with (and I really need it):
> 
> i386-linux-user AND i386-softmmu     (i386 can be replaced with your 
> arch such as: ppc, sparc, x86_64, mips, mipsel and arm)
> 
> That should create an executable called qemu (as stated before) which 
> should not segfault immediatly lol :)

Thank you for your comments.  User virtualization doesn't require
softmmu.  User virtualization translates the ops in the user space
program and then jumps into the real kernel of the host operating system
when a syscall is made - it therefore doesn't need to virtualize all of
the hardware for I/O and the like.  Obviously this only works for
running linux executables of one architecture on linux of possibly
another architecture.

I might mention that none of the other user-space architectures segfault
- just i386 - e.g. arm-linux-user/qemu-arm works just fine.