Re: [Qemu-devel] FreeBSD/amd64 guests with -kernel-kqemu, pagefault at mov %r10d, %gs

[Mulyadi Santosa]

Hi...

On Wed, May 7, 2008 at 1:59 AM, Juergen Lock <address@hidden> wrote:
> ..before that it does a mov %r10d,%fs which seems to work (%r10d is
>  _udatasel in both cases) so it can't be the segment itself that it
>  doesn't like, or can it?  Anyone have an idea what this might be?
>  (it works without -kernel-kqemu.)

<..snip..>

>  0xffffffff806dc752 <exec_setregs+98>:   mov    4183943(%rip),%r10d        # 
> 0xffffffff80ad9ee0 <_udatasel>
>  0xffffffff806dc759 <exec_setregs+105>:  mov    %r10d,%ds
>  0xffffffff806dc75c <exec_setregs+108>:  mov    %r10d,%es
>  0xffffffff806dc75f <exec_setregs+111>:  mov    %ebx,%ecx
>  0xffffffff806dc761 <exec_setregs+113>:  rdmsr
>  0xffffffff806dc763 <exec_setregs+115>:  mov    %r10d,%fs
>  0xffffffff806dc766 <exec_setregs+118>:  wrmsr
>  0xffffffff806dc768 <exec_setregs+120>:  mov    $0xc0000101,%ecx
>  0xffffffff806dc76d <exec_setregs+125>:  pushfq
>  0xffffffff806dc76e <exec_setregs+126>:  cli
>  0xffffffff806dc76f <exec_setregs+127>:  rdmsr
>  0xffffffff806dc771 <exec_setregs+129>:  mov    %r10d,%gs
>                            failed insn  ^^^^^^^^^^^^^^^^^^

I think I agree somehow accessing %gs is the quirk. let's just hope gs
points to valid entry in GDT or LDT...

But may I ask, what does the effect of "cli" in -kernel-kqemu on
FreeBSD's kqemu?

regards,

Mulyadi.