[systemd-devel] Utility for persistent alternative driver binding

[Andrei Borzenkov]

04.12.2015 12:40, Panu Matilainen пишет:
> Hi all,
> 
> To follow-up on this thread from September-October:
> http://lists.freedesktop.org/archives/systemd-devel/2015-September/034427.html
> 
> http://lists.freedesktop.org/archives/systemd-devel/2015-October/034551.html
> 
> 
> The driverctl utility has matured a bit from the earliest tyre-kicking
> version seen there and now lives at laiskiainen.org/git/?p=driverctl.git
> 
> Since it has everything to do with udev this seems like a reasonable
> forum to advertise it a bit. Quoting from the README a bit:
> 
>> driverctl is a tool for manipulating and inspecting the system
>> device driver choices.
>>
>> Devices are normally assigned to their sole designated kernel driver
>> by default. However in some situations it may be desireable to
>> override that default, for example to try an older driver to
>> work around a regression in a driver or to try an experimental
>> alternative
>> driver. Another common use-case is pass-through drivers and driver
>> stubs to allow userspace to drive the device, such as in case of
>> virtualization.
>>
>> driverctl integrates with udev to support overriding
>> driver selection for both cold- and hotplugged devices from the
>> moment of discovery, but can also change already assigned drivers,
>> assuming they are not in use by the system. The driver overrides
>> created by driverctl are persistent across system reboots
>> by default.
>>
>> Usage
>> -----
>>
>> Find devices currently driven by ixgbe driver:
>>
>> # driverctl -v list-devices | grep ixgbe
>> 0000:01:00.0 ixgbe (Ethernet 10G 4P X520/I350 rNDC)
>> 0000:01:00.1 ixgbe (Ethernet 10G 4P X520/I350 rNDC)
>>
>> Change them to use the vfio-pci driver:
>> # driverctl set-override 0000:01:00.0 vfio-pci
>> # driverctl set-override 0000:01:00.1 vfio-pci
>>
>> Find devices with driver overrides:
>> # driverctl -v list-devices|grep \\*
>> 0000:01:00.0 vfio-pci [*] (Ethernet 10G 4P X520/I350 rNDC)
>> 0000:01:00.1 vfio-pci [*] (Ethernet 10G 4P X520/I350 rNDC)
>>
>> Remove the override from slot 0000:01:00.1:
>> # driverctl unset-override 0000:01:00.1
> 

As was mentioned recently PCI bus numbers may change between reboots, so
you may want to start with something more stable from the very beginning.

> The other reason for posting here is: is there interest in having such a
> utility would find home in udev/systemd?
> 
> Note that I'm not trying to sell you the current shell-spaghetti
> implementation, its mostly just a demonstration of the interface which
> is modeled after the various *ctl utilities in systemd. The idea is to
> rewrite it properly in C anyway, but at this point it'd be useful to
> know from style/infrastructure/etc perspective whether there's interest
> in having such a thing included in systemd afterall.
> 
>     - Panu -
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