From mboxrd@z Thu Jan 1 00:00:00 1970 From: Konrad Rzeszutek Wilk Subject: Re: Shared memory and event channel Date: Tue, 23 Feb 2010 09:47:38 -0500 Message-ID: <20100223144738.GC25741@phenom.dumpdata.com> References: <29b32d341002211058l7e283336pa4fdfd0dc0b7124b@mail.gmail.com> <1266787199.24577.18.camel@agari.van.xensource.com> <29b32d341002211533k4956a129ifff18281cfa92e41@mail.gmail.com> <1266825344.4996.183.camel@ramone.somacoma.net> <29b32d341002220936q2f6f3cdaif3cbb766d1e644d1@mail.gmail.com> <1266874463.27288.57.camel@agari.van.xensource.com> <29b32d341002221416t4e00b899q18e07a69ad24b07f@mail.gmail.com> <1266917906.11737.5928.camel@zakaz.uk.xensource.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <1266917906.11737.5928.camel@zakaz.uk.xensource.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Ian Campbell Cc: Ritu kaur , "xen-devel@lists.xensource.com" , Daniel Stodden List-Id: xen-devel@lists.xenproject.org On Tue, Feb 23, 2010 at 09:38:26AM +0000, Ian Campbell wrote: > On Mon, 2010-02-22 at 22:16 +0000, Ritu kaur wrote: > > > > All I need to is access NIC registers via domU's(network controller > > will still be working normally). Using PCI passthrough solves the > > problem for a domU, however, it doesn't solve when multiple domU's > > wanting to read NIC registers(ex. statistics). > > Direct access to hardware registers and availability of the device to > multiple guest domains are mutually exclusive configurations under Xen > (in the absence of additional technologies such as SR-IOV). > > The paravirtual front and back devices contain no hardware specific > functionality, in this configuration all hardware specific knowledge is > contained in the driver in domain 0. Guests use regular L2 or L3 > mechanisms such as bridging, NAT or routing to obtain a path to the > physical hardware but they are never aware of that physical hardware. > > PCI passthrough allows a guest direct access to a PCI device but this is > obviously incompatible with access from multiple guests (again, unless > you have SR-IOV or something similar) What if the netback was set be able to work in guest mode? This way you could export it out to the guests?