Re: [Qemu-devel] [Xen-devel] qemu(-dm): aborting on wrong mmio size?

[Laszlo Ersek]

On 01/31/12 11:36, Jan Beulich wrote:
> > > > On 31.01.12 at 10:34, Laszlo Ersek<address@hidden>  wrote:
> > in the qemu-xen-unstable tree
> > (git://xenbits.xen.org/qemu-xen-unstable.git), the do_inp() function
> > [i386-dm/helper2.c] makes the process exit if the operand size is wrong.
> > Blame: 6040eea5 ("More files imported from xen-unstable
> > 17192:59b8768d0d0d").
> >
> > In the qemu tree (git://git.qemu.org/qemu.git), the do_inp() function
> > [xen-all.c] does the same (via hw_error() / abort()). Blame: 9ce94e7c
> > ("xen: Initialize event channels and io rings").
> >
> > Is it justified to kill the emulator when this happens (eg. memory
> > mapped IO with 64-bit operand)?
>
> Afaict, this is not about MMIO, but PIO.

One possible way seems to be (see 
http://xenbits.xensource.com/hg/linux-2.6.18-xen.hg/rev/1141):

vmx_hpw_miss() [xen/arch/ia64/vmx/vmx_fault.c]
-> emulate_io_inst() [xen/arch/ia64/vmx/mmio.c]
  -> mmio_access()
    -> legacy_io_access()
      -> vmx_send_assist_req() [xen/arch/ia64/vmx/vmx_support.c]
        -> notify_via_xen_event_channel() [xen/common/event_channel.c]

and in qemu-xen-unstable,

cpu_handle_ioreq() [i386-dm/helper2.c], set up in main_loop()
-> __handle_ioreq()
  -> cpu_ioreq_pio()
    -> do_inp()

Thanks,
Laszlo