Proxmox PCIe Passthrough

Intel CPU

Edit grub

nano /etc/default/grub


To this: GRUB_CMDLINE_LINUX_DEFAULT=”quiet intel_iommu=on”


Add required kernel modules

nano /etc/modules


IOMMU interrupt remapping

1) Run the “dmesg | grep ecap” command.

2) On the IOMMU lines, the hexadecimal value after “ecap” indicates whether interrupt remapping is supported. If the last character of this value is an 8, 9, a, b, c, d, e, or an f, interrupt remapping is supported. For example, “ecap 1000” indicates there is no interrupt remapping support. “ecap 10207f” indicates interrupt remapping support, as the last character is an “f”.

Interrupt remapping will only be enabled if every IOMMU supports it.

If your system doesn’t support interrupt remapping, you can allow unsafe interrupts with:

echo "options vfio_iommu_type1 allow_unsafe_interrupts=1" > /etc/modprobe.d/iommu_unsafe_interrupts.conf


Verify IOMMU isolation

To have pci passthrough working fine, you need dedicated iommu group for your pci devices. You should have something like this:

find /sys/kernel/iommu_groups/ -type l


Determine your PCI card address, and configure your VM

Locate your card using “lspci”.  The address should be in the form of: 01:00.0

Manually edit the node.conf file.  It can be located at: /etc/pve/qemu-server/vmid.conf.

Add this line to the end of the file:

hostpci0: 01:00.0


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