From mboxrd@z Thu Jan 1 00:00:00 1970 From: Martin Roth Subject: Sharing MMIO page with DomU on a system with no IOMMU Date: Mon, 15 Oct 2012 10:50:49 -0600 Message-ID: <507C3EE9.9040806@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: xen-devel@lists.xen.org List-Id: xen-devel@lists.xenproject.org Hi - I'm trying to share an MMIO page from Dom0 running linux with a DomU running an RTOS so that I can access the GPIO registers directly. The system I need to get this working on does not have an IOMMU. I'm aware of the security issues of sharing this area, but don't believe it's an issue in this case. I've got a Linux module set up and can share memory between the two domains using the grant table, but I haven't been able to get this to work for the MMIO page. Can anyone give me a pointer on how I should go about doing this? I need the area to actually be shared between both domains, not simply owned by the RTOS. Thanks. Martin Roth