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Date: Tue, 31 Jan 2012 10:34:37 +0100
From: Laszlo Ersek <lersek@redhat.com>
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Subject: [Qemu-devel] qemu(-dm): aborting on wrong mmio size?
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To: "xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>, qemu-devel@nongnu.org
Cc: Miroslav Rezanina <mrezanin@redhat.com>, Petr Matousek <pmatouse@redhat.com>

Hi,

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)? What would happen on real hardware? If 
it's "undefined", wouldn't it be "better" (for some definition of 
"better") to return a constant?

Thank you,
Laszlo