From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bob Liu Subject: Re: [RFC] VirtFS support on Xen Date: Sat, 23 Jan 2016 13:33:40 +0800 Message-ID: <56A310B4.3080808@oracle.com> References: <20160121102844.GP1691@citrix.com> <56A0B7E0.20606@citrix.com> <20160121105958.GR1691@citrix.com> <56A2084A.8010803@oracle.com> <20160122105035.GZ1691@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail6.bemta3.messagelabs.com ([195.245.230.39]) by lists.xen.org with esmtp (Exim 4.72) (envelope-from ) id 1aMqpe-0002df-AU for xen-devel@lists.xenproject.org; Sat, 23 Jan 2016 05:33:54 +0000 In-Reply-To: <20160122105035.GZ1691@citrix.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Wei Liu Cc: Xen-devel , David Vrabel List-Id: xen-devel@lists.xenproject.org On 01/22/2016 06:50 PM, Wei Liu wrote: > On Fri, Jan 22, 2016 at 06:45:30PM +0800, Bob Liu wrote: >> Hi Wei, >> >> On 01/21/2016 06:59 PM, Wei Liu wrote: >>> On Thu, Jan 21, 2016 at 10:50:08AM +0000, David Vrabel wrote: >>>> On 21/01/16 10:28, Wei Liu wrote: >>>>> [RFC] VirtFS support on Xen >>>>> >>>>> # Introduction >>>>> >>>>> QEMU/KVM supports file system passthrough via an interface called >>>>> VirtFS [0]. VirtFS is in turn implemented with 9pfs protocol [1] and >>>>> VirtIO transport. >>>>> >>>>> Xen used to have its own implementation of file system passthrough >>>>> called XenFS, but that has been inactive for a few years. The latest >>>>> update was in 2009 [2]. >>>>> >>>>> This project aims to add VirtFS support on Xen. This is more >>>>> sustainable than inventing our own wheel.# >>>> >>>> What's the use case for this? Who wants this feature? >>>> >>> >>> Anyone who wants file system passthrough. More specifically, VM-based >>> container solutions can share files from host file system. >>> >> >> I'm a bit confused, can't we just use the VirtFS of Qemu? >> E.g >> ./configure --with-extra-qemuu-configure-args="--enable-virtfs" >> > > Yes, in theory you can -- with VirtIO transport. But I'm not sure if > Virtio has been fixed to work with Xen. That also means you need QEMU > emulation, which we don't really need (or want) when running in PV or > PVH mode. > Just make sure if I get it right, in the KVM case: Linux guest(v9fs-client) -> VirtIO transport -> Qemu(v9fs-server) -> Local file system in Host And your plan is: DomU(v9fs-client) -> XEN transport:grant map based -> Qemu(v9fs-server) -> Local file system in Dom0 Which means we need to implement a XEN-transport in linux/net/9p/, and also make Qemu can recognize this transport because we need Qemu to run as the v9fs-server anyway? Bob