From: Jason Gunthorpe <jgg@nvidia.com>
To: Alex Williamson <alex.williamson@redhat.com>
Cc: Yishai Hadas <yishaih@nvidia.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
Subject: Re: [PATCH V2 mlx5-next 12/14] vfio/mlx5: Implement vfio_pci driver for mlx5 devices
Date: Tue, 19 Oct 2021 16:23:28 -0300 [thread overview]
Message-ID: <20211019192328.GZ2744544@nvidia.com> (raw)
In-Reply-To: <20211019124352.74c3b6ba.alex.williamson@redhat.com>
On Tue, Oct 19, 2021 at 12:43:52PM -0600, Alex Williamson wrote:
> > + /* Running switches on */
> > + if (((old_state ^ state) & VFIO_DEVICE_STATE_RUNNING) &&
> > + (state & VFIO_DEVICE_STATE_RUNNING)) {
> > + ret = mlx5vf_pci_unfreeze_device(mvdev);
> > + if (ret)
> > + return ret;
> > + ret = mlx5vf_pci_unquiesce_device(mvdev);
> > + if (ret) {
> > + vmig->vfio_dev_state = VFIO_DEVICE_STATE_ERROR;
> > + return ret;
> > + }
> > + }
>
> Per previous discussion, I understand that freeze and quiesce are
> loosely stop-responding-to-dma and stop-sending-dma, respectively.
> Once we're quiesced and frozen, device state doesn't change. What are
> the implications to userspace that we don't expose a quiesce state
> (yet)? I'm wondering if this needs to be resolved before we introduce
> our first in-tree user of the uAPI (and before QEMU support becomes
> non-experimental). Thanks,
The prototype patch I saw added a 4th bit to the state which was
1 == 'not dma initiating'
As you suggested I think a cap bit someplace should be defined if the
driver supports the 4th bit.
Otherwise, I think it is backwards compatible, the new logic would be
two ifs
if ((flipped & STATE_NDMA) &&
(flipped & (STATE_NDMA | STATE_RUNNING)) == STATE_NDMA | STATE_RUNNING)
mlx5vf_pci _quiesce_device()
[..]
if ((flipped == (STATE_NDMA)) &&
(flipped & (STATE_NDMA | STATE_RUNNING)) == STATE_RUNNING)
mlx5vf_pci_unquiesce_device()
Sequenced before/after the other calls to quiesce_device
So if userspace doesn't use it then the same driver behavior is kept,
as it never sees STATE_NDMA flip
Asking for STATE_NDMA !STATE_RUNNING is just ignored because !RUNNING
already implies NDMA
.. and some optimization of the logic to avoid duplicated work
Jason
next prev parent reply other threads:[~2021-10-19 19:23 UTC|newest]
Thread overview: 100+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-19 10:58 [PATCH V2 mlx5-next 00/14] Add mlx5 live migration driver Yishai Hadas
2021-10-19 10:58 ` [PATCH V2 mlx5-next 01/14] PCI/IOV: Add pci_iov_vf_id() to get VF index Yishai Hadas
2021-10-19 10:58 ` [PATCH V2 mlx5-next 02/14] net/mlx5: Reuse exported virtfn index function call Yishai Hadas
2021-10-19 10:58 ` [PATCH V2 mlx5-next 03/14] net/mlx5: Disable SRIOV before PF removal Yishai Hadas
2021-10-19 10:58 ` [PATCH V2 mlx5-next 04/14] PCI/IOV: Add pci_iov_get_pf_drvdata() to allow VF reaching the drvdata of a PF Yishai Hadas
2021-10-19 10:58 ` [PATCH V2 mlx5-next 05/14] net/mlx5: Expose APIs to get/put the mlx5 core device Yishai Hadas
2021-10-19 10:58 ` [PATCH V2 mlx5-next 06/14] vdpa/mlx5: Use mlx5_vf_get_core_dev() to get PF device Yishai Hadas
2021-10-19 11:16 ` Max Gurtovoy
2021-10-20 8:58 ` Yishai Hadas
2021-10-19 10:58 ` [PATCH V2 mlx5-next 07/14] vfio: Fix VFIO_DEVICE_STATE_SET_ERROR macro Yishai Hadas
2021-10-19 10:58 ` [PATCH V2 mlx5-next 08/14] vfio: Add a macro for VFIO_DEVICE_STATE_ERROR Yishai Hadas
2021-10-19 15:48 ` Alex Williamson
2021-10-19 15:50 ` Alex Williamson
2021-10-20 7:35 ` Yishai Hadas
2021-10-19 10:58 ` [PATCH V2 mlx5-next 09/14] vfio/pci_core: Make the region->release() function optional Yishai Hadas
2021-10-19 10:58 ` [PATCH V2 mlx5-next 10/14] net/mlx5: Introduce migration bits and structures Yishai Hadas
2021-10-19 10:58 ` [PATCH V2 mlx5-next 11/14] vfio/mlx5: Expose migration commands over mlx5 device Yishai Hadas
2021-10-19 10:58 ` [PATCH V2 mlx5-next 12/14] vfio/mlx5: Implement vfio_pci driver for mlx5 devices Yishai Hadas
2021-10-19 18:43 ` Alex Williamson
2021-10-19 19:23 ` Jason Gunthorpe [this message]
2021-10-19 20:58 ` Alex Williamson
2021-10-19 23:04 ` Jason Gunthorpe
2021-10-20 8:28 ` Yishai Hadas
2021-10-20 16:52 ` Alex Williamson
2021-10-20 18:59 ` Jason Gunthorpe
2021-10-20 21:07 ` Alex Williamson
2021-10-21 9:34 ` Cornelia Huck
2021-10-21 21:47 ` Alex Williamson
2021-10-25 12:29 ` Jason Gunthorpe
2021-10-25 14:28 ` Alex Williamson
2021-10-25 14:56 ` Jason Gunthorpe
2021-10-26 14:42 ` Alex Williamson
2021-10-26 15:18 ` Jason Gunthorpe
2021-10-26 19:50 ` Alex Williamson
2021-10-26 23:43 ` Jason Gunthorpe
2021-10-27 19:05 ` Alex Williamson
2021-10-27 19:23 ` Jason Gunthorpe
2021-10-28 15:08 ` Cornelia Huck
2021-10-29 0:26 ` Jason Gunthorpe
2021-10-29 7:35 ` Yishai Hadas
2021-10-28 15:30 ` Alex Williamson
2021-10-28 23:47 ` Jason Gunthorpe
2021-10-29 6:57 ` Cornelia Huck
2021-10-29 7:48 ` Yishai Hadas
2021-10-29 10:32 ` Shameerali Kolothum Thodi
2021-10-29 12:15 ` Jason Gunthorpe
2021-10-29 22:06 ` Alex Williamson
2021-11-01 17:25 ` Jason Gunthorpe
2021-11-02 11:19 ` Shameerali Kolothum Thodi
2021-11-02 14:56 ` Alex Williamson
2021-11-02 15:54 ` Jason Gunthorpe
2021-11-02 16:22 ` Alex Williamson
2021-11-02 16:36 ` Jason Gunthorpe
2021-11-02 20:15 ` Alex Williamson
2021-11-03 12:09 ` Jason Gunthorpe
2021-11-03 15:44 ` Alex Williamson
2021-11-03 16:10 ` Jason Gunthorpe
2021-11-03 18:04 ` Alex Williamson
2021-11-04 11:19 ` Cornelia Huck
2021-11-05 16:53 ` Cornelia Huck
2021-11-16 16:59 ` Cornelia Huck
2021-11-05 13:24 ` Jason Gunthorpe
2021-11-05 15:31 ` Alex Williamson
2021-11-15 23:29 ` Jason Gunthorpe
2021-11-16 17:57 ` Alex Williamson
2021-11-16 19:25 ` Jason Gunthorpe
2021-11-16 21:10 ` Alex Williamson
2021-11-17 1:48 ` Jason Gunthorpe
2021-11-18 18:15 ` Alex Williamson
2021-11-22 19:18 ` Jason Gunthorpe
2021-11-08 8:53 ` Tian, Kevin
2021-11-08 12:35 ` Jason Gunthorpe
2021-11-09 0:58 ` Tian, Kevin
2021-11-09 12:45 ` Jason Gunthorpe
2021-10-25 16:34 ` Dr. David Alan Gilbert
2021-10-25 17:55 ` Alex Williamson
2021-10-25 18:47 ` Dr. David Alan Gilbert
2021-10-25 19:15 ` Jason Gunthorpe
2021-10-26 8:40 ` Dr. David Alan Gilbert
2021-10-26 12:13 ` Jason Gunthorpe
2021-10-26 14:52 ` Alex Williamson
2021-10-26 15:56 ` Jason Gunthorpe
2021-10-26 14:29 ` Alex Williamson
2021-10-26 14:51 ` Dr. David Alan Gilbert
2021-10-26 15:25 ` Jason Gunthorpe
2021-10-20 8:01 ` Yishai Hadas
2021-10-20 16:25 ` Jason Gunthorpe
2021-10-21 10:46 ` Yishai Hadas
2021-10-19 10:58 ` [PATCH V2 mlx5-next 13/14] vfio/pci: Expose vfio_pci_aer_err_detected() Yishai Hadas
2021-10-19 10:58 ` [PATCH V2 mlx5-next 14/14] vfio/mlx5: Use its own PCI reset_done error handler Yishai Hadas
2021-10-19 18:55 ` Alex Williamson
2021-10-19 19:10 ` Jason Gunthorpe
2021-10-20 8:46 ` Yishai Hadas
2021-10-20 16:46 ` Jason Gunthorpe
2021-10-20 17:45 ` Alex Williamson
2021-10-20 18:57 ` Jason Gunthorpe
2021-10-20 21:38 ` Alex Williamson
2021-10-21 10:39 ` Yishai Hadas
2021-11-17 16:42 ` vfio migration discussions (was: [PATCH V2 mlx5-next 00/14] Add mlx5 live migration driver) Cornelia Huck
2021-11-17 17:47 ` Jason Gunthorpe
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