From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jike Song Subject: Re: VFIO no-iommu Date: Thu, 14 Jan 2016 14:03:34 +0800 Message-ID: References: <60420822.AbcfvjLZCk@xps13> <566B4A50.9090607@6wind.com> <1449874953.20509.6.camel@redhat.com> <26FA93C7ED1EAA44AB77D62FBE1D27BA6747CE55@IRSMSX108.ger.corp.intel.com> <1450198398.6042.32.camel@redhat.com> <20151216040408.GA18363@sivlogin002.ir.intel.com> <1450240711.2674.11.camel@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Cc: "dev@dpdk.org" To: Alex Williamson Return-path: Received: from mail-io0-f170.google.com (mail-io0-f170.google.com [209.85.223.170]) by dpdk.org (Postfix) with ESMTP id 0B29F8DB3 for ; Thu, 14 Jan 2016 07:03:35 +0100 (CET) Received: by mail-io0-f170.google.com with SMTP id 1so395811491ion.1 for ; Wed, 13 Jan 2016 22:03:34 -0800 (PST) In-Reply-To: <1450240711.2674.11.camel@redhat.com> List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" On Wed, Dec 16, 2015 at 12:38 PM, Alex Williamson wrote: > > So it works. Is it acceptable? Useful? Sufficiently complete? Does > it imply deprecating the uio interface? I believe the feature that > started this discussion was support for MSI/X interrupts so that VFs > can support some kind of interrupt (uio only supports INTx since it > doesn't allow DMA). Implementing that would be the ultimate test of > whether this provides dpdk with not only a more consistent interface, > but the feature dpdk wants that's missing in uio. Thanks, > Hi Alex, Sorry for jumping in. Just being curious, how does VFIO No-IOMMU mode support DMA from userspace drivers? If I understand correctly, due to the absence of IOMMU, pcidev has to use physaddr to start a DMA transaction, but how it is supposed to get physaddr from userspace drivers, /proc//pagemap or something else? -- Thanks, Jike