From mboxrd@z Thu Jan  1 00:00:00 1970
From: Laszlo Ersek <lersek@redhat.com>
Subject: Re: [Xen-devel] qemu(-dm): aborting on wrong mmio size?
Date: Tue, 31 Jan 2012 11:54:45 +0100
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To: Jan Beulich <JBeulich@suse.com>
Cc: Miroslav Rezanina <mrezanin@redhat.com>, "xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>, Petr Matousek <pmatouse@redhat.com>, qemu-devel@nongnu.org
List-Id: xen-devel@lists.xenproject.org

On 01/31/12 11:36, Jan Beulich wrote:
>>>> On 31.01.12 at 10:34, Laszlo Ersek<lersek@redhat.com>  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