From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:51921) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XWtEL-0002rJ-MV for qemu-devel@nongnu.org; Wed, 24 Sep 2014 16:32:14 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XWtEC-0002Uo-Lc for qemu-devel@nongnu.org; Wed, 24 Sep 2014 16:32:05 -0400 Received: from mail-qg0-x234.google.com ([2607:f8b0:400d:c04::234]:48396) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XWtEC-0002Ss-FX for qemu-devel@nongnu.org; Wed, 24 Sep 2014 16:31:56 -0400 Received: by mail-qg0-f52.google.com with SMTP id j5so5805041qga.39 for ; Wed, 24 Sep 2014 13:31:50 -0700 (PDT) Sender: Paolo Bonzini Message-ID: <54232A2F.9020107@redhat.com> Date: Wed, 24 Sep 2014 22:31:43 +0200 From: Paolo Bonzini MIME-Version: 1.0 References: <1411588026.24563.153.camel@ul30vt.home> In-Reply-To: <1411588026.24563.153.camel@ul30vt.home> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [IGDVFIO] [PATCH 3/8] RFC and help completing: Intel IGD Direct Assignment with VFIO List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Alex Williamson , Andrew Barnes Cc: intel-gfx@lists.freedesktop.org, qemu-devel@nongnu.org Il 24/09/2014 21:47, Alex Williamson ha scritto: > So the opregion is mapped by a config write on the IGD device itself and > the other 3 regions, that we know about so far, are mapped via writes to > the host bridge. AFAIU the opregion is mapped by the (host) BIOS, that writes the address to a well-known scratch dword in the configuration space. The host reads from the dword and finds the opregion that way. Paolo