From mboxrd@z Thu Jan 1 00:00:00 1970 From: Laszlo Ersek Subject: Re: [Xen-devel] qemu(-dm): aborting on wrong mmio size? Date: Tue, 31 Jan 2012 12:04:14 +0100 Message-ID: <4F27CAAE.8070602@redhat.com> References: <4F27B5AD.9050709@redhat.com> <4F27D232020000780007012B@nat28.tlf.novell.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4F27D232020000780007012B@nat28.tlf.novell.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+gceq-qemu-devel=gmane.org@nongnu.org Sender: qemu-devel-bounces+gceq-qemu-devel=gmane.org@nongnu.org To: Jan Beulich Cc: Miroslav Rezanina , "xen-devel@lists.xensource.com" , Petr Matousek , 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 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