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

[Laszlo Ersek <lersek@xxxxxxxxxx>]

On 01/31/12 11:36, Jan Beulich wrote:
> > > > On 31.01.12 at 10:34, Laszlo Ersek<lersek@xxxxxxxxxx>  wrote:
> > Is it justified to kill the emulator when this happens (eg. memory
> > mapped IO with 64-bit operand)?
> The AMD manual specifies that REX.W is ignored; the Intel manual
> doesn't mention REX at all here. However, if a decoder incorrectly
> decodes the guest instruction, that's a bug there. So imo qemu
> validly treats this condition as fatal.
From the Itanium(R) SDM rev 2.3,

10.7.2.1 I/O Port Addressing Restrictions

    For the 64MB physical I/O port block the following operations are
    undefined and may result in unpredictable processor operation;
    references larger than 4-bytes, [...]

It seems that not only a decoding failure can trigger this.

Laszlo

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel