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Date:   Mon, 12 Dec 2022 08:55:41 +0100
From:   Christoph Hellwig <hch@lst.de>
To:     Max Gurtovoy <mgurtovoy@nvidia.com>
Cc:     Jason Gunthorpe <jgg@ziepe.ca>, Christoph Hellwig <hch@lst.de>,
        Lei Rao <lei.rao@intel.com>, kbusch@kernel.org, axboe@fb.com,
        kch@nvidia.com, sagi@grimberg.me, alex.williamson@redhat.com,
        cohuck@redhat.com, yishaih@nvidia.com,
        shameerali.kolothum.thodi@huawei.com, kevin.tian@intel.com,
        mjrosato@linux.ibm.com, linux-kernel@vger.kernel.org,
        linux-nvme@lists.infradead.org, kvm@vger.kernel.org,
        eddie.dong@intel.com, yadong.li@intel.com, yi.l.liu@intel.com,
        Konrad.wilk@oracle.com, stephen@eideticom.com, hang.yuan@intel.com,
        Oren Duer <oren@nvidia.com>
Subject: Re: [RFC PATCH 1/5] nvme-pci: add function nvme_submit_vf_cmd to
 issue admin commands for VF driver.
Message-ID: <20221212075541.GC11162@lst.de>
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On Sun, Dec 11, 2022 at 01:39:37PM +0200, Max Gurtovoy wrote:
> 1. Need to define a concept of a "virtual subsystem". A primary controller 
> will be able to create a virtual subsystem. Inside this subsystem the 
> primary controller will be the master ("the controlling") of the migration 
> process. It will also be able to add secondary controllers to this virtual 
> subsystem and assign "virtual controller ID" to it.
> something like:
> - nvme virtual_subsys_create --dev=/dev/nvme1 --virtual_nqn="my_v_nqn_1" 
> --dev_vcid = 1
> - nvme virtual_subsys_add --dev=/dev/nvme1 --virtual_nqn="my_v_nqn_1" 
> --secondary_dev=/dev/nvme2 --secondary_dev_vcid=20

Yes. Note that there is a bit more state than just the NQN.  You also
need at least a serial number, and also probably a different vendor
ID (the PCI vendor ID that is also mirror in Identify Controller and
the IEEE OUI), and new unique namespace identifier.