From mboxrd@z Thu Jan 1 00:00:00 1970 From: Anthony Liguori Subject: Re: [Qemu-devel] [PATCH 2/6] PCI DMA API Date: Sun, 30 Mar 2008 09:44:57 -0500 Message-ID: <47EFA769.7090201@us.ibm.com> References: <1206827760-4566-1-git-send-email-aliguori@us.ibm.com> <1206827760-4566-2-git-send-email-aliguori@us.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: kvm-devel@lists.sourceforge.net, Marcelo Tosatti , qemu-devel@nongnu.org, Aurelien Jarno To: Blue Swirl Return-path: In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kvm-devel-bounces@lists.sourceforge.net Errors-To: kvm-devel-bounces@lists.sourceforge.net List-Id: kvm.vger.kernel.org Blue Swirl wrote: > On 3/30/08, Anthony Liguori wrote: > >> This patch introduces a PCI DMA API and some generic code to support other DMA >> APIs. Two types are introduced: PhysIOVector and IOVector. A DMA API >> maps a PhysIOVector, which is composed of target_phys_addr_t, into an IOVector, >> which is composed of void *. >> > > This looks like it wouldn't scale to handle the Sparc systems. There > we want to make more translation steps from DVMA addresses to physical > in DMA controller and IOMMU and only in the final stage to void *. To > handle this, probably there should be an opaque parameter and some way > to register the translation function. Otherwise the API looks OK. > I think having the PCI DMA API translate PhysIOVector => PhysIOVector would help. Then it becomes pretty easy to just call the DMA controller for additional translation from the IOMMU. Does that sound right? I don't quite understand what role the opaque parameter would serve. Regards, Anthony Liguori ------------------------------------------------------------------------- Check out the new SourceForge.net Marketplace. It's the best place to buy or sell services for just about anything Open Source. http://ad.doubleclick.net/clk;164216239;13503038;w?http://sf.net/marketplace