From: Christoph Hellwig <hch@lst.de>
To: Jason Gunthorpe <jgg@nvidia.com>
Cc: Alex Williamson <alex.williamson@redhat.com>,
Christoph Hellwig <hch@lst.de>,
Max Gurtovoy <mgurtovoy@nvidia.com>,
Alexey Kardashevskiy <aik@ozlabs.ru>,
cohuck@redhat.com, kvm@vger.kernel.org,
linux-kernel@vger.kernel.org, liranl@nvidia.com, oren@nvidia.com,
tzahio@nvidia.com, leonro@nvidia.com, yarong@nvidia.com,
aviadye@nvidia.com, shahafs@nvidia.com, artemp@nvidia.com,
kwankhede@nvidia.com, ACurrid@nvidia.com, cjia@nvidia.com,
yishaih@nvidia.com, mjrosato@linux.ibm.com
Subject: Re: [PATCH 8/9] vfio/pci: export nvlink2 support into vendor vfio_pci drivers
Date: Mon, 22 Mar 2021 16:11:25 +0100 [thread overview]
Message-ID: <20210322151125.GA1051@lst.de> (raw)
In-Reply-To: <20210319200749.GB2356281@nvidia.com>
On Fri, Mar 19, 2021 at 05:07:49PM -0300, Jason Gunthorpe wrote:
> The way the driver core works is to first match against the already
> loaded driver list, then trigger an event for module loading and when
> new drivers are registered they bind to unbound devices.
>
> So, the trouble is the event through userspace because the kernel
> can't just go on to use vfio_pci until it knows userspace has failed
> to satisfy the load request.
>
> One answer is to have userspace udev have the "hook" here and when a
> vfio flavour mod alias is requested on a PCI device it swaps in
> vfio_pci if it can't find an alternative.
>
> The dream would be a system with no vfio modules loaded could do some
>
> echo "vfio" > /sys/bus/pci/xxx/driver_flavour
>
> And a module would be loaded and a struct vfio_device is created for
> that device. Very easy for the user.
Maybe I did not communicate my suggestion last week very well. My
idea is that there are no different pci_drivers vs vfio or not,
but different personalities of the same driver.
So the interface would still look somewhat like your suggestion above,
although I'd prefer something like:
echo 1 > /sys/bus/pci/xxx/use_vfio
How would the flow look like for the various cases?
a) if a driver is bound, and it supports the enable_vfio method that
is called, and everything is controller by the driver, which uses
symbols exorted from vfio/vfio_pci to implement the functionality
b) if a driver is bound, but does not support the enable_vfio method
it is unbound and vfio_pci is bound instead, continue at c)
c) use the normal current vfio flow
do the reverse on a
echo 0 > /sys/bus/pci/xxx/use_vfio
next prev parent reply other threads:[~2021-03-22 15:12 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-09 8:33 [PATCH v3 0/9] Introduce vfio-pci-core subsystem Max Gurtovoy
2021-03-09 8:33 ` [PATCH 1/9] vfio-pci: rename vfio_pci.c to vfio_pci_core.c Max Gurtovoy
2021-03-09 8:33 ` [PATCH 2/9] vfio-pci: rename vfio_pci_private.h to vfio_pci_core.h Max Gurtovoy
2021-03-09 8:33 ` [PATCH 3/9] vfio-pci: rename vfio_pci_device to vfio_pci_core_device Max Gurtovoy
2021-03-09 8:33 ` [PATCH 4/9] vfio-pci: introduce vfio_pci_core subsystem driver Max Gurtovoy
2021-03-09 8:33 ` [PATCH 5/9] vfio/pci: introduce vfio_pci_device structure Max Gurtovoy
2021-03-09 8:33 ` [PATCH 6/9] vfio-pci-core: export vfio_pci_register_dev_region function Max Gurtovoy
2021-03-09 8:33 ` [PATCH 7/9] vfio/pci_core: split nvlink2 to nvlink2gpu and npu2 Max Gurtovoy
2021-03-10 8:08 ` Christoph Hellwig
2021-03-09 8:33 ` [PATCH 8/9] vfio/pci: export nvlink2 support into vendor vfio_pci drivers Max Gurtovoy
2021-03-10 6:39 ` Alexey Kardashevskiy
2021-03-10 12:57 ` Max Gurtovoy
2021-03-10 13:02 ` Jason Gunthorpe
2021-03-10 14:24 ` Alexey Kardashevskiy
2021-03-10 19:40 ` Jason Gunthorpe
2021-03-11 1:20 ` Alexey Kardashevskiy
2021-03-11 1:34 ` Jason Gunthorpe
2021-03-11 1:42 ` Alexey Kardashevskiy
2021-03-11 2:00 ` Jason Gunthorpe
2021-03-11 7:54 ` Alexey Kardashevskiy
2021-03-11 9:44 ` Max Gurtovoy
2021-03-11 16:51 ` Jason Gunthorpe
2021-03-11 17:01 ` Jason Gunthorpe
2021-03-10 14:19 ` Alexey Kardashevskiy
2021-03-11 1:10 ` Max Gurtovoy
2021-03-19 15:23 ` Alex Williamson
2021-03-19 16:17 ` Jason Gunthorpe
2021-03-19 16:20 ` Christoph Hellwig
2021-03-19 16:28 ` Jason Gunthorpe
2021-03-19 16:34 ` Christoph Hellwig
2021-03-19 17:36 ` Alex Williamson
2021-03-19 20:07 ` Jason Gunthorpe
2021-03-19 21:08 ` Alex Williamson
2021-03-19 22:59 ` Jason Gunthorpe
2021-03-20 4:40 ` Alex Williamson
2021-03-21 12:58 ` Jason Gunthorpe
2021-03-22 16:40 ` Alex Williamson
2021-03-23 19:32 ` Jason Gunthorpe
2021-03-24 2:39 ` Alexey Kardashevskiy
2021-03-29 23:10 ` Alex Williamson
2021-04-01 13:04 ` Cornelia Huck
2021-04-01 13:12 ` Jason Gunthorpe
2021-04-01 21:49 ` Alex Williamson
2021-03-22 15:11 ` Christoph Hellwig [this message]
2021-03-22 16:44 ` Jason Gunthorpe
2021-03-23 13:17 ` Christoph Hellwig
2021-03-23 13:42 ` Jason Gunthorpe
2021-03-09 8:33 ` [PATCH 9/9] vfio/pci: export igd support into vendor vfio_pci driver Max Gurtovoy
2021-03-10 8:15 ` Christoph Hellwig
2021-03-10 12:31 ` Jason Gunthorpe
2021-03-11 11:37 ` Christoph Hellwig
2021-03-11 12:09 ` Max Gurtovoy
2021-03-11 15:43 ` Jason Gunthorpe
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