On Thu, 17 May 2018 13:12:07 -0400 Kyle Marek <pspps...@gmail.com> wrote:
> On 05/17/2018 10:27 AM, Alex Williamson wrote: > > On Thu, 17 May 2018 12:56:49 +0800 > > Eddie Yen <missile0...@gmail.com> wrote: > > > >> Hi everyone, > >> > >> IME, you can set VID:PID by adding "options vfio-pci" into conf file and > >> put at modprobe.d > >> So that VFIO can take over the device that had same VID:PID when boot. > >> > >> But how can I set this option by using PCI Address without using override > >> script? > > There's no such module option, what's wrong with a script? Part of the > > reason we don't have such a module option is that PCI addresses are not > > persistent, they can change based on devices added or removed, or even > > motherboard BIOS updates. Userspace has more flexibility for managing > > this and is fully able to do so via initrd scripts and modprobe.d. > > Thanks, > > > > Alex > > That's a good point. > > However, I had an environment where I needed to pass through one of two > devices with the same PCI IDs. I accomplished it with an install command > in my modprobe config. > > I can probably make this look at other factors before overriding the > driver, but the following config might work well enough if the PCI IDs > don't change: > > # For each PCI device listed in the for-loop, override their assigned driver > # to vfio-pci, for usage with PCI-passthrough. > # > # Please make sure to include vfio-pci in the initrd, or some other modules > # will likely claim the devices first. This can be done on systems that use > # initramfs-tools by adding "vfio-pci" to /etc/initramfs-tools/modules > install vfio-pci for dev in 0000:03:00.0 0000:03:00.1; do echo vfio-pci > > "/sys/bus/pci/devices/$dev/driver_override"; done; /sbin/modprobe > --ignore-install vfio-pci $CMDLINE_OPTS > > # Load vfio-pci before some other drivers so they don't claim devices first. > # The pre-drm line should handle all graphics drivers. > softdep snd_hda_intel pre: vfio-pci > softdep drm pre: vfio-pci > > > This worked well for me in dracut and initramfs-tools initrds with the > vfio-pci module included. Yes, this is a good demonstration of how userspace can easily accomplish this through modprobe.d softdeps and custom install options. A more persistence focused version of the above might do the same knowing that we're looking for all devices device downstream of the root port at 0000:00:01.0, and would look something like: install vfio-pci for dev in $(find /sys/devices/pci0000:00/0000:00:01.0/ -maxdepth 1 -mindepth 1 -type d -name "????:??:??.?"); do echo vfio-pci > $dev/driver_override; done; modprobe --ignore-install... or even for override in $(find /sys/devices/pci0000:00/0000:00:01.0/ -mindepth 2 -name driver_override); do echo vfio-pci > $override; done... There are countless ways to do this, including ways that take advantage of PCI slots information provided through ACPI if the system supports it. Thanks, Alex _______________________________________________ vfio-users mailing list vfio-users@redhat.com https://www.redhat.com/mailman/listinfo/vfio-users
