Re: Fresh install of Windows XP hangs early in boot?

[Marcelo Tosatti <mtosatti@redhat.com>]

On Tue, Jul 29, 2008 at 12:39:53PM -0700, Roland Dreier wrote:
> I built with debugging symbols, and this seems to be an issue with SCSI
> disk emulation.  The traceback is:
> 
> #0  0x00007fc086d7dd10 in memcpy () from /lib/libc.so.6
> #1  0x00000000004a319b in cpu_physical_memory_rw (addr=108661608,
>     buf=0x7fff904ca190 "\224['\206\210\030z\006I�A", len=4, is_write=0)
>     at /users/rdreier/kvm-deb.git/qemu/exec.c:2847
> #2  0x000000000041f0c2 in lsi_execute_script (s=0x2ef7a30) at ../cpu-all.h:924
> #3  0x000000000049bd91 in qcow_aio_read_cb (opaque=0x3018d70, ret=0) at block-qcow2.c:840
> #4  0x000000000041cba0 in qemu_aio_poll () at /users/rdreier/kvm-deb.git/qemu/block-raw-posix.c:513
> #5  0x000000000040b38a in main_loop_wait (timeout=<value optimized out>)
>     at /users/rdreier/kvm-deb.git/qemu/vl.c:7777
> #6  0x00000000004f607a in kvm_main_loop () at /users/rdreier/kvm-deb.git/qemu/qemu-kvm.c:587
> #7  0x0000000000412b46 in main (argc=<value optimized out>, argv=0x7fff904cb0c8)
>     at /users/rdreier/kvm-deb.git/qemu/vl.c:7811
> 
> and no progress ever seems to be made (the same address is read over and
> over)
> 
> I'm trying again with IDE instead of SCSI disks.  But I would like to
> help debug the SCSI emulation... will look at it further later, and I'm
> happy to provide any info someone else could use.

Hi Roland,

Known problem:
http://www.nabble.com/LSI:-avoid-infinite-loops-p17116605.html

Windows driver has scripts code which busy loops on main memory. Since
that executes in vcpu context, the cpu won't ever get a chance to change
the variable which the SCSI emulation is looping at.

The proposed hack, however, is half-assed (see Paul Brook's comments on
that thread).