From: Cornelia Huck <cohuck@redhat.com>
To: Jason Gunthorpe <jgg@nvidia.com>
Cc: Yishai Hadas <yishaih@nvidia.com>,
alex.williamson@redhat.com, bhelgaas@google.com,
saeedm@nvidia.com, linux-pci@vger.kernel.org,
kvm@vger.kernel.org, netdev@vger.kernel.org, kuba@kernel.org,
leonro@nvidia.com, kwankhede@nvidia.com, mgurtovoy@nvidia.com,
maorg@nvidia.com, ashok.raj@intel.com, kevin.tian@intel.com,
shameerali.kolothum.thodi@huawei.com
Subject: Re: [PATCH V8 mlx5-next 09/15] vfio: Define device migration protocol v2
Date: Thu, 24 Feb 2022 11:41:44 +0100 [thread overview]
Message-ID: <87ilt47dhz.fsf@redhat.com> (raw)
In-Reply-To: <20220224004622.GD409228@nvidia.com>
On Wed, Feb 23 2022, Jason Gunthorpe <jgg@nvidia.com> wrote:
> On Wed, Feb 23, 2022 at 06:06:13PM +0100, Cornelia Huck wrote:
>> On Sun, Feb 20 2022, Yishai Hadas <yishaih@nvidia.com> wrote:
>> > +/*
>> > + * Indicates the device can support the migration API through
>> > + * VFIO_DEVICE_FEATURE_MIG_DEVICE_STATE. If present flags must be non-zero and
>> > + * VFIO_DEVICE_FEATURE_MIG_DEVICE_STATE is supported. The RUNNING and
>>
>> I'm having trouble parsing this. I think what it tries to say is that at
>> least one of the flags defined below must be set?
>>
>> > + * ERROR states are always supported if this GET succeeds.
>>
>> What about the following instead:
>>
>> "Indicates device support for the migration API through
>> VFIO_DEVICE_FEATURE_MIG_DEVICE_STATE. If present, the RUNNING and ERROR
>> states are always supported. Support for additional states is indicated
>> via the flags field; at least one of the flags defined below must be
>> set."
>
> Almost, 'at least VFIO_MIGRATION_STOP_COPY must be set'
It feels a bit odd to split the mandatory states between a base layer
(RUNNING/ERROR) and the ones governed by VFIO_MIGRATION_STOP_COPY. Do we
want to keep the possibility of a future implementation that does not
use the semantics indicated by VFIO_MIGRATION_STOP_COPY? If yes, it
should be "one of the flags" and the flags that require
VFIO_MIGRATION_STOP_COPY to be set as well need to note that
dependency. If not, we should explicitly tag VFIO_MIGRATION_STOP_COPY as
mandatory (so that the flag's special status is obvious.)
next prev parent reply other threads:[~2022-02-24 10:42 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-20 9:57 [PATCH V8 mlx5-next 00/15] Add mlx5 live migration driver and v2 migration protocol Yishai Hadas
2022-02-20 9:57 ` [PATCH V8 mlx5-next 01/15] PCI/IOV: Add pci_iov_vf_id() to get VF index Yishai Hadas
2022-02-20 9:57 ` [PATCH V8 mlx5-next 02/15] net/mlx5: Reuse exported virtfn index function call Yishai Hadas
2022-02-20 9:57 ` [PATCH V8 mlx5-next 03/15] net/mlx5: Disable SRIOV before PF removal Yishai Hadas
2022-02-20 9:57 ` [PATCH V8 mlx5-next 04/15] PCI/IOV: Add pci_iov_get_pf_drvdata() to allow VF reaching the drvdata of a PF Yishai Hadas
2022-02-20 9:57 ` [PATCH V8 mlx5-next 05/15] net/mlx5: Expose APIs to get/put the mlx5 core device Yishai Hadas
2022-02-20 9:57 ` [PATCH V8 mlx5-next 06/15] net/mlx5: Introduce migration bits and structures Yishai Hadas
2022-02-23 19:09 ` Alex Williamson
2022-02-23 19:17 ` Jason Gunthorpe
2022-02-20 9:57 ` [PATCH V8 mlx5-next 07/15] net/mlx5: Add migration commands definitions Yishai Hadas
2022-02-20 9:57 ` [PATCH V8 mlx5-next 08/15] vfio: Have the core code decode the VFIO_DEVICE_FEATURE ioctl Yishai Hadas
2022-02-22 16:48 ` Cornelia Huck
2022-02-22 18:13 ` Jason Gunthorpe
2022-02-20 9:57 ` [PATCH V8 mlx5-next 09/15] vfio: Define device migration protocol v2 Yishai Hadas
2022-02-22 1:55 ` Tian, Kevin
2022-02-22 23:53 ` Alex Williamson
2022-02-23 0:21 ` Jason Gunthorpe
2022-02-23 1:09 ` Alex Williamson
2022-02-23 2:02 ` Tian, Kevin
2022-02-23 2:47 ` Jason Gunthorpe
2022-02-23 17:06 ` Cornelia Huck
2022-02-24 0:46 ` Jason Gunthorpe
2022-02-24 10:41 ` Cornelia Huck [this message]
2022-02-24 12:39 ` Jason Gunthorpe
2022-02-20 9:57 ` [PATCH V8 mlx5-next 10/15] vfio: Extend the device migration protocol with RUNNING_P2P Yishai Hadas
2022-02-22 2:00 ` Tian, Kevin
2022-02-23 17:42 ` Alex Williamson
2022-02-24 0:47 ` Jason Gunthorpe
2022-02-20 9:57 ` [PATCH V8 mlx5-next 11/15] vfio: Remove migration protocol v1 documentation Yishai Hadas
2022-02-20 9:57 ` [PATCH V8 mlx5-next 12/15] vfio/mlx5: Expose migration commands over mlx5 device Yishai Hadas
2022-02-20 9:57 ` [PATCH V8 mlx5-next 13/15] vfio/mlx5: Implement vfio_pci driver for mlx5 devices Yishai Hadas
2022-02-20 9:57 ` [PATCH V8 mlx5-next 14/15] vfio/pci: Expose vfio_pci_core_aer_err_detected() Yishai Hadas
2022-02-20 9:57 ` [PATCH V8 mlx5-next 15/15] vfio/mlx5: Use its own PCI reset_done error handler Yishai Hadas
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