From mboxrd@z Thu Jan  1 00:00:00 1970
From: Marcelo Tosatti <mtosatti@redhat.com>
Subject: Re: Fresh install of Windows XP hangs early in boot?
Date: Tue, 29 Jul 2008 18:23:32 -0300
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References: <aday73k34zw.fsf@cisco.com> <adaod4g33vo.fsf@cisco.com> <adaiquo32eu.fsf@cisco.com>
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To: Roland Dreier <rdreier@cisco.com>
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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 SC=
SI
> disk emulation.  The traceback is:
>=20
> #0  0x00007fc086d7dd10 in memcpy () from /lib/libc.so.6
> #1  0x00000000004a319b in cpu_physical_memory_rw (addr=3D108661608,
>     buf=3D0x7fff904ca190 "\224['\206\210\030z\006I=EF=BF=BDA", len=3D=
4, is_write=3D0)
>     at /users/rdreier/kvm-deb.git/qemu/exec.c:2847
> #2  0x000000000041f0c2 in lsi_execute_script (s=3D0x2ef7a30) at ../cp=
u-all.h:924
> #3  0x000000000049bd91 in qcow_aio_read_cb (opaque=3D0x3018d70, ret=3D=
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=3D<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=3D<value optimized out>, argv=3D=
0x7fff904cb0c8)
>     at /users/rdreier/kvm-deb.git/qemu/vl.c:7811
>=20
> and no progress ever seems to be made (the same address is read over =
and
> over)
>=20
> 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 chang=
e
the variable which the SCSI emulation is looping at.

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