From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: Re: virtio scsi host draft specification, v3 Date: Wed, 29 Jun 2011 06:27:50 -0400 Message-ID: <20110629102750.GA11648@infradead.org> References: <1504884387.187692.1307716550265.JavaMail.root@zmail07.collab.prod.int.phx2.redhat.com> <4DF71E28.6070009@suse.de> <4E0AE36B.9010500@redhat.com> <20110629100752.GA27744@infradead.org> <4E0AFD2A.80102@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Christoph Hellwig , Stefan Hajnoczi , Paolo Bonzini , Christoph Hellwig , Stefan Hajnoczi , kvm@vger.kernel.org, "Michael S. Tsirkin" , qemu-devel , Linux Kernel Mailing List , Linux Virtualization , "Nicholas A. Bellinger" To: Hannes Reinecke Return-path: Content-Disposition: inline In-Reply-To: <4E0AFD2A.80102@suse.de> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On Wed, Jun 29, 2011 at 12:23:38PM +0200, Hannes Reinecke wrote: > The general idea here is that we can support NPIV. > With NPIV we'll have several scsi_hosts, each of which is assigned a > different set of LUNs by the array. > With virtio we need to able to react on LUN remapping on the array > side, ie we need to be able to issue a 'REPORT LUNS' command and > add/remove LUNs on the fly. This means we have to expose the > scsi_host in some way via virtio. > > This is impossible with a one-to-one mapping between targets and > LUNs. The actual bus-level pass-through will be just on the SCSI > layer, ie 'REPORT LUNS' should be possible. If and how we do a LUN > remapping internally on the host is a totally different matter. > Same goes for the transport details; I doubt we will expose all the > dingy details of the various transports, but rather restrict > ourselves to an abstract transport. If we want to support traditional NPIV that's what we have to do. I still hope we'll see broad SR-IOV support for FC adapters soon, which would ease all this greatly.