From: Max Gurtovoy <mgurtovoy@nvidia.com>
To: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Alex Williamson <alex.williamson@redhat.com>,
Leon Romanovsky <leon@kernel.org>,
Doug Ledford <dledford@redhat.com>,
Yishai Hadas <yishaih@nvidia.com>,
Bjorn Helgaas <bhelgaas@google.com>,
"David S. Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>,
Kirti Wankhede <kwankhede@nvidia.com>, <kvm@vger.kernel.org>,
<linux-kernel@vger.kernel.org>, <linux-pci@vger.kernel.org>,
<linux-rdma@vger.kernel.org>, <netdev@vger.kernel.org>,
Saeed Mahameed <saeedm@nvidia.com>,
Cornelia Huck <cohuck@redhat.com>
Subject: Re: [PATCH mlx5-next 2/7] vfio: Add an API to check migration state transition validity
Date: Thu, 30 Sep 2021 00:48:55 +0300 [thread overview]
Message-ID: <29835bf4-d094-ae6d-1a32-08e65847b52c@nvidia.com> (raw)
In-Reply-To: <20210929161433.GA1808627@ziepe.ca>
On 9/29/2021 7:14 PM, Jason Gunthorpe wrote:
> On Wed, Sep 29, 2021 at 06:28:44PM +0300, Max Gurtovoy wrote:
>
>>> So you have a device that's actively modifying its internal state,
>>> performing I/O, including DMA (thereby dirtying VM memory), all while
>>> in the _STOP state? And you don't see this as a problem?
>> I don't see how is it different from vfio-pci situation.
> vfio-pci provides no way to observe the migration state. It isn't
> "000b"
Alex said that there is a problem of compatibility.
I migration SW is not involved, nobody will read this migration state.
>> Maybe we need to rename STOP state. We can call it READY or LIVE or
>> NON_MIGRATION_STATE.
> It was a poor choice to use 000b as stop, but it doesn't really
> matter. The mlx5 driver should just pre-init this readable to running.
I guess we can do it for this reason. There is no functional problem nor
compatibility issue here as was mentioned.
But still we need the kernel to track transitions. We don't want to
allow moving from RESUMING to SAVING state for example. How this
transition can be allowed ?
In this case we need to fail the request from the migration SW...
>
> Jason
next prev parent reply other threads:[~2021-09-29 21:49 UTC|newest]
Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <cover.1632305919.git.leonro@nvidia.com>
2021-09-22 10:38 ` [PATCH mlx5-next 1/7] PCI/IOV: Provide internal VF index Leon Romanovsky
2021-09-22 21:59 ` Bjorn Helgaas
2021-09-23 6:35 ` Leon Romanovsky
2021-09-24 13:08 ` Bjorn Helgaas
2021-09-25 10:10 ` Leon Romanovsky
2021-09-25 17:41 ` Bjorn Helgaas
2021-09-26 6:36 ` Leon Romanovsky
2021-09-26 20:23 ` Bjorn Helgaas
2021-09-27 11:55 ` Leon Romanovsky
2021-09-27 14:47 ` Bjorn Helgaas
2021-09-22 10:38 ` [PATCH mlx5-next 2/7] vfio: Add an API to check migration state transition validity Leon Romanovsky
2021-09-23 10:33 ` Shameerali Kolothum Thodi
2021-09-23 11:17 ` Leon Romanovsky
2021-09-23 13:55 ` Max Gurtovoy
2021-09-24 7:44 ` Shameerali Kolothum Thodi
2021-09-24 9:37 ` Kirti Wankhede
2021-09-26 9:09 ` Max Gurtovoy
2021-09-26 16:17 ` Shameerali Kolothum Thodi
2021-09-27 18:24 ` Max Gurtovoy
2021-09-27 18:29 ` Shameerali Kolothum Thodi
2021-09-27 22:46 ` Alex Williamson
2021-09-27 23:12 ` Jason Gunthorpe
2021-09-28 19:19 ` Alex Williamson
2021-09-28 19:35 ` Jason Gunthorpe
2021-09-28 20:18 ` Alex Williamson
2021-09-29 16:16 ` Jason Gunthorpe
2021-09-29 18:06 ` Alex Williamson
2021-09-29 18:26 ` Jason Gunthorpe
2021-09-29 10:57 ` Max Gurtovoy
2021-09-29 10:44 ` Max Gurtovoy
2021-09-29 12:35 ` Alex Williamson
2021-09-29 13:26 ` Max Gurtovoy
2021-09-29 13:50 ` Alex Williamson
2021-09-29 14:36 ` Max Gurtovoy
2021-09-29 15:17 ` Alex Williamson
2021-09-29 15:28 ` Max Gurtovoy
2021-09-29 16:14 ` Jason Gunthorpe
2021-09-29 21:48 ` Max Gurtovoy [this message]
2021-09-29 22:44 ` Alex Williamson
2021-09-30 9:25 ` Max Gurtovoy
2021-09-30 12:41 ` Alex Williamson
2021-09-29 23:21 ` Jason Gunthorpe
2021-09-30 9:34 ` Max Gurtovoy
2021-09-30 14:47 ` Jason Gunthorpe
2021-09-30 15:32 ` Max Gurtovoy
2021-09-30 16:24 ` Jason Gunthorpe
2021-09-30 16:51 ` Max Gurtovoy
2021-09-30 17:01 ` Jason Gunthorpe
2021-09-22 10:38 ` [PATCH mlx5-next 3/7] vfio/pci_core: Make the region->release() function optional Leon Romanovsky
2021-09-23 13:57 ` Max Gurtovoy
2021-09-22 10:38 ` [PATCH mlx5-next 4/7] net/mlx5: Introduce migration bits and structures Leon Romanovsky
2021-09-24 5:48 ` Mark Zhang
2021-09-22 10:38 ` [PATCH mlx5-next 5/7] net/mlx5: Expose APIs to get/put the mlx5 core device Leon Romanovsky
2021-09-22 10:38 ` [PATCH mlx5-next 6/7] mlx5_vfio_pci: Expose migration commands over mlx5 device Leon Romanovsky
2021-09-28 20:22 ` Alex Williamson
2021-09-29 5:36 ` Leon Romanovsky
2021-09-22 10:38 ` [PATCH mlx5-next 7/7] mlx5_vfio_pci: Implement vfio_pci driver for mlx5 devices Leon Romanovsky
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