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From: Jason Gunthorpe <jgg@ziepe.ca>
To: Alex Williamson <alex.williamson@redhat.com>
Cc: 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: Mon, 27 Sep 2021 20:12:39 -0300	[thread overview]
Message-ID: <20210927231239.GE3544071@ziepe.ca> (raw)
In-Reply-To: <20210927164648.1e2d49ac.alex.williamson@redhat.com>

On Mon, Sep 27, 2021 at 04:46:48PM -0600, Alex Williamson wrote:
> > +	enum { MAX_STATE = VFIO_DEVICE_STATE_RESUMING };
> > +	static const u8 vfio_from_state_table[MAX_STATE + 1][MAX_STATE + 1] = {
> > +		[VFIO_DEVICE_STATE_STOP] = {
> > +			[VFIO_DEVICE_STATE_RUNNING] = 1,
> > +			[VFIO_DEVICE_STATE_RESUMING] = 1,
> > +		},
> 
> Our state transition diagram is pretty weak on reachable transitions
> out of the _STOP state, why do we select only these two as valid?

I have no particular opinion on specific states here, however adding
more states means more stuff for drivers to implement and more risk
driver writers will mess up this uAPI.

So only on those grounds I'd suggest to keep this to the minimum
needed instead of the maximum logically possible..

Also, probably the FSM comment from the uapi header file should be
moved into a function comment above this function?

Jason

  reply	other threads:[~2021-09-27 23:12 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 [this message]
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
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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