From mboxrd@z Thu Jan 1 00:00:00 1970 From: Keir Fraser Subject: Re: [help]: handling IO instructions for hybrid Date: Wed, 08 Feb 2012 19:18:45 -0800 Message-ID: References: <20120208181720.377bb098@mantra.us.oracle.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20120208181720.377bb098@mantra.us.oracle.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Mukesh Rathor Cc: "Xen-devel@lists.xensource.com" , Ian Campbell , "stefano.stabellini@eu.citrix.com" List-Id: xen-devel@lists.xenproject.org On 08/02/2012 18:17, "Mukesh Rathor" wrote: > On Mon, 06 Feb 2012 19:41:23 +0000 > Keir Fraser wrote: > >> On 07/02/2012 02:26, "Mukesh Rathor" wrote: >>> >>> I am figuring io access for hybrid guests, dom0 and domU. I see >>> that there are two ways: PV -> emulate_privileged_op(), or hvm >>> handles via handle_mmio()/handle_pio(). I am not familiar with >>> either one, and would help me lot if anybody expert in that can >>> suggest which way hybrid should go, both dom0 and domU. Any >>> suggestions would help. If there are any docs on this, that would >>> be great too. >> >> Probably the PV route, for dom0 and domU. Really most things you want >> to do, the PV route is going to be the right way (unless you are >> PVHVM'ing certain things, e.g., like using EPT assistance for >> pagetable handling). >> >> -- Keir > > Thanks Keir. Just to confirm, the hybrid should continue to request > iopl of 1, right? I'm not sure it matters since the hybrid guest runs in ring 0 of non-root context I believe? Since ring 1 is in that case unused, it doesn't matter whether iopl is 0 or 1. -- Keir