From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:34288) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Ry39p-0004V5-2B for qemu-devel@nongnu.org; Thu, 16 Feb 2012 10:22:10 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Ry39k-00011R-FT for qemu-devel@nongnu.org; Thu, 16 Feb 2012 10:22:04 -0500 Received: from mx1.redhat.com ([209.132.183.28]:24890) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Ry39k-00011L-7U for qemu-devel@nongnu.org; Thu, 16 Feb 2012 10:22:00 -0500 Message-ID: <4F3D1F11.5070804@redhat.com> Date: Thu, 16 Feb 2012 17:21:53 +0200 From: Avi Kivity MIME-Version: 1.0 References: <3ac2ae28b19aabebd3937b87ff365b481f990779.1329232393.git.jan.kiszka@siemens.com> In-Reply-To: <3ac2ae28b19aabebd3937b87ff365b481f990779.1329232393.git.jan.kiszka@siemens.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v3 4/9] target-i386: Add infrastructure for reporting TPR MMIO accesses List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Jan Kiszka Cc: Anthony Liguori , Gleb Natapov , kvm@vger.kernel.org, Marcelo Tosatti , qemu-devel , Blue Swirl On 02/14/2012 05:13 PM, Jan Kiszka wrote: > Note that KVM without in-kernel irqchip will report the address after > the instruction that triggered a write access. In contrast, read > accesses will return the precise information. > Well this is wierd. We could retro-doc one or the other behaviour, but this-on-read-but-that-on-write is just too strange. The documented way of dealing with this is to queue a signal and reenter the guest. kvm will perform anything it needs to complete the instruction (perhaps issuing more mmio, say if someone used movsd to read the APIC) and then exit on the signal. By then rip will point exactly after the instruction. -- error compiling committee.c: too many arguments to function