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Cornelis Technical Documentation

6.3.2. IOMMU: Passthrough Mode

IOMMU is often enabled by default but needs to be set to passthrough mode in order for the hfi1 driver to function properly.

Steps:

  1. Edit /etc/default/grub to change or add GRUB_CMDLINE_LINUX to include:

    iommu=pt

  2. Update GRUB:

    On RHEL and SLES:

    grub2-mkconfig --update-bls-cmdline -o /etc/grub2.cfg

    On Ubuntu:

    update-grub

  3. Reboot.

  4. Confirm the setting is in place:

    cat /proc/cmdline
... iommu=pt ...