[vfio-users] Convenience script for binding to vfio-pci

[Andre Richter]

Hi,

I added Alex' suggestions and also wrote a bash version.

https://github.com/andre-richter/vfio-pci-bind

Cheers,
Andre

Alex Williamson <alex.williamson at redhat.com> schrieb am Mo., 14. Sep. 2015
um 17:36 Uhr:

> On Mon, 2015-09-14 at 17:24 +0200, Andre Richter wrote:
> > Hi Alex,
> >
> > thanks for the quick feedback!
> > I'll incorporate your changes tomorrow.
> >
> > 2015-09-14 16:51 GMT+02:00 Alex Williamson <alex.williamson at redhat.com>:
> > > Hi Andre,
> > >
> > > On Mon, 2015-09-14 at 14:23 +0000, Andre Richter wrote:
> > >> Hi,
> > >>
> > >> just in case anybody is interested, I want to share a little
> convenience
> > >> script of mine:
> > >>
> > >> https://github.com/andre-richter/vfio-pci-bind
> > >>
> > >> This script takes a Bus:Device:Function string of the form "00:00.0"
> > >> as command line argument and:
> > >>
> > >> 1. Unbinds all devices that are in the same iommu group as the
> supplied
> > >> device from their current driver (except PCIe bridges).
> > >>
> > >> 2. Binds to vfio-pci:
> > >>   1. The supplied device.
> > >>   2. All unbound devices that have the same device_id and vendor_id
> as the
> > >> supplied device.
> > >>   3. All devices that are in the same iommu group.
> > >>
> > >> 3. Transfers ownership of the respective iommu groups inside
> /dev/vfio to
> > >> $SUDO_USER
> > >>
> > >> Script must be executed via sudo!
> > >
> > >
> > > This looks fragile:
> > >
> > > unless File.exist?('/sys/bus/pci/devices/0000:00:00.0/iommu/')
> > >   puts 'No signs of an IOMMU. Check your hardware and/or linux cmdline
> parameters.'
> > >   puts 'Use intel_iommu=on or iommu=pt iommu=1'
> > >   exit
> > > end
> > >
> > > Why not check the iommu link for the device to be attached, or look
> > > in /sys/class/iommu rather than assume device 0000:00:00.0?
> > >
> > > TARGET_DEV_SYSFS_PATH = "/sys/bus/pci/devices/0000:#{bdf}/"
> > >
> > > You're assuming domain 0000.
> >
> > I have never seen a machine with a domain greater than 0000, so I got
> > lazy there, but ofc you're right, will fix.
> >
> > >
> > > # Do not care about bridges
> > > dev_sysfs_paths.delete_if { |dsp| File.read(dsp + '/class')[0..5] ==
> '0x0604' }
> > >
> > > Testing for HEADER_TYPE 0 would be more compatible and match the patch
> I
> > > proposed for whitelisting all bridges, not just those w/o a driver or
> > > bound to pcieport.  Ex
> > >
> > >
> > > if [ $(( 0x$(setpci -s 0000:00:1c.0 0e.b) & 0x7f )) -ne 0 ]; then
> > >     echo bridge
> > > fi
> > >
> > >
> > >   # Add id to vfio-pci driver
> > >   File.write('/sys/bus/pci/drivers/vfio-pci/new_id', devid)
> > >
> > > If you used /sys/bus/pci/devices/ssss:bb:dd.f/driver_override you could
> > > avoid the "feature" of binding all devices with the same vendor:device
> > > ID.
> >
> > Actually I was wondering what a reasonable approach is when freeing an
> > IOMMU group with multiple devices.
> > Leave the other devices unbound? Bind them to pci-stub? What do you
> suggest?
>
> I'd just do something like this:
>
> To bind:
>
> echo vfio-pci > .../devices/ssss:bb:dd.f/driver_override
> echo ssss:bb:dd.f > .../drivers/vfio-pci/bind
> echo > .../devices/ssss:bb:dd.f/driver_override
>
> To unbind:
>
> echo ssss:bb:dd.f > .../drivers/vfio-pci/unbind
> echo ssss:bb:dd.f > /sys/bus/pci/drivers_probe
>
> The new_id, remove_id interface is racy, so if you don't touch it,
> drivers_probe should always pickup what the kernel would have had the
> device bound to.
>
> > > # Adjust ownership
> > > ids = ENV['SUDO_UID'] + ':' + ENV['SUDO_GID']
> > > Dir.glob('/dev/vfio/[0-9]*').each { |f| `chown #{ids} #{f}` }
> > >
> > > Is this changing the ownership of *all* the groups to the current user?
> > > Why not just the group affected?  Thanks,
> > >
> > > Alex
> > >
> >
> > Cheers,
> > Andre
>
>
>
>
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