From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:41921) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1THAPE-0001RR-Jd for qemu-devel@nongnu.org; Thu, 27 Sep 2012 05:29:20 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1THAP8-0004A6-RB for qemu-devel@nongnu.org; Thu, 27 Sep 2012 05:29:16 -0400 Received: from mx1.redhat.com ([209.132.183.28]:44899) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1THAP8-0004A2-JA for qemu-devel@nongnu.org; Thu, 27 Sep 2012 05:29:10 -0400 Message-ID: <50641C5F.2030202@redhat.com> Date: Thu, 27 Sep 2012 11:29:03 +0200 From: Paolo Bonzini MIME-Version: 1.0 References: <50597D1F.3070607@redhat.com> <505991A2.6090709@siemens.com> <5059954A.50408@redhat.com> <50600F7B.5080106@redhat.com> <50602B0A.1020403@redhat.com> <50641976.3020405@redhat.com> In-Reply-To: <50641976.3020405@redhat.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [big lock] Discussion about the convention of device's DMA each other after breaking down biglock List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Avi Kivity Cc: Jan Kiszka , Marcelo Tosatti , liu ping fan , Anthony Liguori , "qemu-devel@nongnu.org" Il 27/09/2012 11:16, Avi Kivity ha scritto: > needs to be a little more complicated. After translation, we need to > look up the address again in a different phys_map. So a MemoryRegion > that is an iommu needs to hold its own phys_map pointer for the lookup. > > But let's ignore the problem for now, we have too much on our plate. > With a recursive big lock, there is no problem with iommus, yes? So as > long as there is no intersection between converted devices and platforms > with iommus, we're safe. pSeries has both PCI and iommu, but I think no one should be using e1000 on a pSeries. virtio-net is per-spec not going through the iommu. Paolo