From: Jason Gunthorpe <jgg@ziepe.ca>
To: Max Gurtovoy <mgurtovoy@nvidia.com>
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 11:47:52 -0300 [thread overview]
Message-ID: <20210930144752.GA67618@ziepe.ca> (raw)
In-Reply-To: <d8324d96-c897-b914-16c6-ad0bbb9b13a5@nvidia.com>
On Thu, Sep 30, 2021 at 12:34:19PM +0300, Max Gurtovoy wrote:
> > When we add the migration extension this cannot change, so after
> > open_device() the device should be operational.
>
> if it's waiting for incoming migration blob, it is not running.
It cannot be waiting for a migration blob after open_device, that is
not backwards compatible.
Just prior to open device the vfio pci layer will generate a FLR to
the function so we expect that post open_device has a fresh from reset
fully running device state.
> > The reported state in the migration region should accurately reflect
> > what the device is currently doing. If the device is operational then
> > it must report running, not stopped.
>
> STOP in migration meaning.
As Alex and I have said several times STOP means the internal state is
not allowed to change.
> > driver will see RESUMING toggle off so it will trigger a
> > de-serialization
>
> You mean stop serialization ?
No, I mean it will take all the migration data that has been uploaded
through the migration region and de-serialize it into active device
state.
> > driver will see SAVING toggled on so it will serialize the new state
> > (either the pre-copy state or the post-copy state dpending on the
> > running bit)
>
> lets leave the bits and how you implement the state numbering aside.
You've missed the point. This isn't a FSM. It is a series of three
control bits that we have assigned logical meaning their combinatoins.
The algorithm I gave is a control centric algorithm not a state
centric algorithm and matches the direction Alex thought this was
being designed for.
> If you finish resuming you can move to a new state (that we should add) =>
> RESUMED.
It is not a state machine. Once you stop prentending this is
implementing a FSM Alex's position makes perfect sense.
Jason
next prev parent reply other threads:[~2021-09-30 14:47 UTC|newest]
Thread overview: 58+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-22 10:38 [PATCH mlx5-next 0/7] Add mlx5 live migration driver Leon Romanovsky
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
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 [this message]
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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