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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 16:01:31 +0100	[thread overview]
Message-ID: <20221206150131.GA32365@lst.de> (raw)
In-Reply-To: <Y49WNo7XWZ2aFfds@ziepe.ca>

On Tue, Dec 06, 2022 at 10:48:22AM -0400, Jason Gunthorpe wrote:
> Sadly in Linux we don't have a SRIOV VF lifecycle model that is any
> use.

Beward:  The secondary function might as well be a physical function
as well.  In fact one of the major customers for "smart" multifunction
nvme devices prefers multi-PF devices over SR-IOV VFs. (and all the
symmetric dual ported devices are multi-PF as well).

So this isn't really about a VF live cycle, but how to manage life
migration, especially on the receive / restore side.  And restoring
the entire controller state is extremely invasive and can't be done
on a controller that is in any classic form live.  In fact a lot
of the state is subsystem-wide, so without some kind of virtualization
of the subsystem it is impossible to actually restore the state.

To cycle back to the hardware that is posted here, I'm really confused
how it actually has any chance to work and no one has even tried
to explain how it is supposed to work.

  reply	other threads:[~2022-12-06 15:06 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 [this message]
2022-12-06 15:28                     ` Jason Gunthorpe
2022-12-06 15:35                       ` Christoph Hellwig
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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