From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751312AbdAPUSH (ORCPT ); Mon, 16 Jan 2017 15:18:07 -0500 Received: from mx3-phx2.redhat.com ([209.132.183.24]:33505 "EHLO mx3-phx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750834AbdAPUSF (ORCPT ); Mon, 16 Jan 2017 15:18:05 -0500 Date: Mon, 16 Jan 2017 15:17:59 -0500 (EST) From: Paolo Bonzini To: Hannes Reinecke Cc: Fam Zheng , linux-kernel@vger.kernel.org, "Martin K. Petersen" , linux-scsi@vger.kernel.org, "Michael S. Tsirkin" , "James E.J. Bottomley" , virtualization@lists.linux-foundation.org, stefanha@redhat.com Message-ID: <886576564.9475841.1484597879593.JavaMail.zimbra@redhat.com> In-Reply-To: <0009b36c-29a9-9486-3fad-197733d905bc@suse.de> References: <20170116160430.11815-1-famz@redhat.com> <0009b36c-29a9-9486-3fad-197733d905bc@suse.de> Subject: Re: [PATCH 0/2] virtio-scsi: Implement FC_HOST feature MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-Originating-IP: [10.4.164.1, 10.5.101.130] X-Mailer: Zimbra 8.0.6_GA_5922 (ZimbraWebClient - FF50 (Linux)/8.0.6_GA_5922) Thread-Topic: virtio-scsi: Implement FC_HOST feature Thread-Index: D6yAYGXotN3TGjYcMjDDKJBMUPQxjg== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > How it this supposed to work? > You do export the WWPN/WWNN of the associated host to the guest (nb: > will get interesting for non NPIV setups ...), but virtio scsi will > still do a LUN remapping. > IE the LUNs you see on the host will be different from the LUNs > presented to the guest. This is taken care of in the host by presenting to the host all LUNs from a host's NPIV vHBA. (Libvirt probably would be the one taking care of this, because QEMU may not have enough permissions). > Plus you don't _actually_ expose the FC host, but rather the WWPN of the > host presenting the LUN. > So how do you handle LUNs from different FC hosts on the guest? I'm not sure I understand. Neither I nor Fam know this stuff very well, but we are trying to do the same as Hyper-V (and other proprietary hypervisors too). > Overall, I'm not overly happy with this approach. > You already added WWPN ids to the virtio transport, so why didn't you > update the LUN field, too, to avoid this ominous LUN remapping? Is this your old idea of adding a separate target field to commands, in order to support 64-bit LUNs? That is separate, and most FC drivers only default to 16-bit LUNs anyway. > And we really should make sure to have a single FC host in the guest > presenting all LUNs. Yes, of course. Paolo