From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paolo Bonzini Subject: Re: [PATCH 0/2] virtio-scsi: Implement FC_HOST feature Date: Mon, 16 Jan 2017 15:17:59 -0500 (EST) Message-ID: <886576564.9475841.1484597879593.JavaMail.zimbra@redhat.com> References: <20170116160430.11815-1-famz@redhat.com> <0009b36c-29a9-9486-3fad-197733d905bc@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <0009b36c-29a9-9486-3fad-197733d905bc@suse.de> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org To: Hannes Reinecke Cc: "James E.J. Bottomley" , linux-scsi@vger.kernel.org, "Martin K. Petersen" , "Michael S. Tsirkin" , linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, stefanha@redhat.com List-Id: linux-scsi@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