From mboxrd@z Thu Jan 1 00:00:00 1970 From: Benjamin Herrenschmidt Subject: Re: [PATCH v5 2/3] virtio_pci: Use the DMA API for virtqueues when possible Date: Tue, 30 Sep 2014 07:06:22 +1000 Message-ID: <1412024782.4285.101.camel@pasglop> References: <6c31406005160303a7ee291a933c267f8e55fa85.1410931077.git.luto@amacapital.net> <1410955351.30672.27.camel@pasglop> <20140917141639.GA13684@redhat.com> <1412023777.4285.93.camel@pasglop> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org List-Archive: List-Post: To: Andy Lutomirski Cc: "linux-s390@vger.kernel.org" , Konrad Rzeszutek Wilk , "Michael S. Tsirkin" , Linux Virtualization , Christian Borntraeger , Paolo Bonzini , "linux390@de.ibm.com" List-ID: On Mon, 2014-09-29 at 13:55 -0700, Andy Lutomirski wrote: > If the eventual solution is to say that virtio 1.0 PCI devices always > respect an IOMMU unless they set a magic flag saying "I'm not real > hardware and I bypass the IOMMU", then I don't really object to that, > except that it'll be a mess if the guest is running Xen. But even Xen > would (I think) be okay if it actually worked by having a new DMA API > operation that says "this device is magically identity mapped" and > then just teaching Xen to implement that. > > But I'm not an OASIS member, so I can't really do this. I agree that > this issue needs to be addressed somehow, but I don't think it needs > to block these patches. I'll let Rusty be the final judge of that (well, when he's back from his vacation that is). Cheers, Ben.