From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:49353) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Sd81Y-0000fE-6f for qemu-devel@nongnu.org; Fri, 08 Jun 2012 18:51:21 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Sd81W-0007Ej-KA for qemu-devel@nongnu.org; Fri, 08 Jun 2012 18:51:19 -0400 Received: from gate.crashing.org ([63.228.1.57]:55055) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Sd81W-0007EX-Ax for qemu-devel@nongnu.org; Fri, 08 Jun 2012 18:51:18 -0400 Message-ID: <1339195870.24838.55.camel@pasglop> From: Benjamin Herrenschmidt Date: Sat, 09 Jun 2012 08:51:10 +1000 In-Reply-To: <4FD24DAE.6040709@freescale.com> References: <6A3DF150A5B70D4F9B66A25E3F7C888D03D71BC1@039-SN2MPN1-022.039d.mgd.msft.net> <1339153301.24838.49.camel@pasglop> <4FD24DAE.6040709@freescale.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Mime-Version: 1.0 Subject: Re: [Qemu-devel] [RFC] Proposal: PCI/PCIe: inbound BAR0 emulation for PCI controller (Root Complex) List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Scott Wood Cc: Wood Scott-B07421 , Yoder Stuart-B08248 , "qemu-devel@nongnu.org" , Bhushan Bharat-R65777 On Fri, 2012-06-08 at 14:08 -0500, Scott Wood wrote: > > Yes, that's basically it. The patches allow you to add a set of > routines > > that will be used for translating DMA accesses to system memory > along > > with map/unmap operations etc... > > How easy is it to have multi-level translation -- PCI controller > translates PCI transactions to host DMA addresses, and the system > IOMMU > translates that into a physical address? Multi level would mean a translation layer at every bridge level, which sucks big time in term of performances. At the moment the patches provide a way to hook a translate function at the bus level. Cheers, Ben.