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From: Christoph Hellwig <hch@lst.de>
To: Jason Gunthorpe <jgg@ziepe.ca>
Cc: 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
Subject: Re: [RFC PATCH 5/5] nvme-vfio: Add a document for the NVMe device
Date: Tue, 6 Dec 2022 16:35:46 +0100	[thread overview]
Message-ID: <20221206153546.GA2266@lst.de> (raw)
In-Reply-To: <Y49fjFD6foGorhmp@ziepe.ca>

On Tue, Dec 06, 2022 at 11:28:12AM -0400, Jason Gunthorpe wrote:
> I'm interested as well, my mental model goes as far as mlx5 and
> hisillicon, so if nvme prevents the VFs from being contained units, it
> is a really big deviation from VFIO's migration design..

In NVMe the controller (which maps to a PCIe physical or virtual
function) is unfortunately not very self contained.  A lot of
state is subsystem-wide, where the subsystem is, roughly speaking,
the container for all controllers that shared storage.  That is
the right thing to do for say dual ported SSDs that are used for
clustering or multi-pathing, for tentant isolation is it about
as wrong as it gets.

There is nothing in the NVMe spec that prohibits your from
implementing multiple subsystems for multiple functions of a PCIe
device, but if you do that there is absolutely no support in the
spec to manage shared resources or any other interaction between
them.

  reply	other threads:[~2022-12-06 15:35 UTC|newest]

Thread overview: 65+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-12-06  5:58 [RFC PATCH 0/5] Add new VFIO PCI driver for NVMe devices Lei Rao
2022-12-06  5:58 ` [RFC PATCH 1/5] nvme-pci: add function nvme_submit_vf_cmd to issue admin commands for VF driver Lei Rao
2022-12-06  6:19   ` Christoph Hellwig
2022-12-06 13:44     ` Jason Gunthorpe
2022-12-06 13:51       ` Keith Busch
2022-12-06 14:27         ` Jason Gunthorpe
2022-12-06 13:58       ` Christoph Hellwig
2022-12-06 15:22         ` Jason Gunthorpe
2022-12-06 15:38           ` Christoph Hellwig
2022-12-06 15:51             ` Jason Gunthorpe
2022-12-06 16:55               ` Christoph Hellwig
2022-12-06 19:15                 ` Jason Gunthorpe
2022-12-07  2:30                   ` Max Gurtovoy
2022-12-07  7:58                     ` Christoph Hellwig
2022-12-09  2:11                       ` Tian, Kevin
2022-12-12  7:41                         ` Christoph Hellwig
2022-12-07  7:54                   ` Christoph Hellwig
2022-12-07 10:59                     ` Max Gurtovoy
2022-12-07 13:46                       ` Christoph Hellwig
2022-12-07 14:50                         ` Max Gurtovoy
2022-12-07 16:35                           ` Christoph Hellwig
2022-12-07 13:34                     ` Jason Gunthorpe
2022-12-07 13:52                       ` Christoph Hellwig
2022-12-07 15:07                         ` Jason Gunthorpe
2022-12-07 16:38                           ` Christoph Hellwig
2022-12-07 17:31                             ` Jason Gunthorpe
2022-12-07 18:33                               ` Christoph Hellwig
2022-12-07 20:08                                 ` Jason Gunthorpe
2022-12-09  2:50                                   ` Tian, Kevin
2022-12-09 18:56                                     ` Dong, Eddie
2022-12-11 11:39                                   ` Max Gurtovoy
2022-12-12  7:55                                     ` Christoph Hellwig
2022-12-12 14:49                                       ` Max Gurtovoy
2022-12-12  7:50                                   ` Christoph Hellwig
2022-12-13 14:01                                     ` Jason Gunthorpe
2022-12-13 16:08                                       ` Christoph Hellwig
2022-12-13 17:49                                         ` Jason Gunthorpe
2022-12-06  5:58 ` [RFC PATCH 2/5] nvme-vfio: add new vfio-pci driver for NVMe device Lei Rao
2022-12-06  5:58 ` [RFC PATCH 3/5] nvme-vfio: enable the function of VFIO live migration Lei Rao
2023-01-19 10:21   ` Max Gurtovoy
2023-02-09  9:09     ` Rao, Lei
2022-12-06  5:58 ` [RFC PATCH 4/5] nvme-vfio: check if the hardware supports " Lei Rao
2022-12-06 13:47   ` Keith Busch
2022-12-06  5:58 ` [RFC PATCH 5/5] nvme-vfio: Add a document for the NVMe device Lei Rao
2022-12-06  6:26   ` Christoph Hellwig
2022-12-06 13:05     ` Jason Gunthorpe
2022-12-06 13:09       ` Christoph Hellwig
2022-12-06 13:52         ` Jason Gunthorpe
2022-12-06 14:00           ` Christoph Hellwig
2022-12-06 14:20             ` Jason Gunthorpe
2022-12-06 14:31               ` Christoph Hellwig
2022-12-06 14:48                 ` Jason Gunthorpe
2022-12-06 15:01                   ` Christoph Hellwig
2022-12-06 15:28                     ` Jason Gunthorpe
2022-12-06 15:35                       ` Christoph Hellwig [this message]
2022-12-06 18:00                         ` Dong, Eddie
2022-12-12  7:57                           ` Christoph Hellwig
2022-12-11 12:05                     ` Max Gurtovoy
2022-12-11 13:21                       ` Rao, Lei
2022-12-11 14:51                         ` Max Gurtovoy
2022-12-12  1:20                           ` Rao, Lei
2022-12-12  8:09                           ` Christoph Hellwig
2022-12-09  2:05         ` Tian, Kevin
2022-12-09 16:53           ` Li, Yadong
2022-12-12  8:11             ` Christoph Hellwig

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