[[qm_pci_passthrough]]
PCI(e) Passthrough
------------------
+ifdef::wiki[]
+:pve-toplevel:
+endif::wiki[]
PCI(e) passthrough is a mechanism to give a virtual machine control over
a PCI device from the host. This can have some advantages over using
hardware, but even then, many modern system can support this.
Please refer to your hardware vendor to check if they support this feature
-under Linux for your specific setup
+under Linux for your specific setup.
Configuration
Once you ensured that your hardware supports passthrough, you will need to do
some configuration to enable PCI(e) passthrough.
-
.IOMMU
-The IOMMU has to be activated on the kernel commandline. The easiest way is to
-enable trough grub. Edit `'/etc/default/grub'' and add the following to the
-'GRUB_CMDLINE_LINUX_DEFAULT' variable:
+First, you have to enable IOMMU support in your BIOS/UEFI. Usually the
+corresponding setting is called `IOMMU` or `VT-d`,but you should find the exact
+option name in the manual of your motherboard.
+
+For Intel CPUs, you may also need to enable the IOMMU on the
+xref:sysboot_edit_kernel_cmdline[kernel command line] for older (pre-5.15)
+kernels by adding:
-* for Intel CPUs:
-+
----
intel_iommu=on
----
-* for AMD CPUs:
-+
-----
- amd_iommu=on
-----
-[[qm_pci_passthrough_update_grub]]
-To bring this change in effect, make sure you run:
+For AMD CPUs it should be enabled automatically.
+
+.IOMMU Passthrough Mode
+
+If your hardware supports IOMMU passthrough mode, enabling this mode might
+increase performance.
+This is because VMs then bypass the (default) DMA translation normally
+performed by the hyper-visor and instead pass DMA requests directly to the
+hardware IOMMU. To enable these options, add:
----
-# update-grub
+ iommu=pt
----
+to the xref:sysboot_edit_kernel_cmdline[kernel commandline].
+
.Kernel Modules
You have to make sure the following modules are loaded. This can be achieved by
enabled.
----
-# dmesg -e DMAR -e IOMMU -e AMD-Vi
+# dmesg | grep -e DMAR -e IOMMU -e AMD-Vi
----
should display that `IOMMU`, `Directed I/O` or `Interrupt Remapping` is
Host Configuration
^^^^^^^^^^^^^^^^^^
-In this case, the host cannot use the card. There are two methods to achieve
+In this case, the host must not use the card. There are two methods to achieve
this:
* pass the device IDs to the options of the 'vfio-pci' modules by adding
the vendor and device IDs obtained by:
+
----
-# lcpci -nn
+# lspci -nn
----
* blacklist the driver completely on the host, ensuring that it is free to bind
xref:qm_pci_passthrough_update_initramfs[update the `initramfs`] again and
reboot after that.
+.Verify Configuration
+
+To check if your changes were successful, you can use
+
+----
+# lspci -nnk
+----
+
+and check your device entry. If it says
+
+----
+Kernel driver in use: vfio-pci
+----
+
+or the 'in use' line is missing entirely, the device is ready to be used for
+passthrough.
+
[[qm_pci_passthrough_vm_config]]
VM Configuration
^^^^^^^^^^^^^^^^
# qm set VMID -hostpci0 00:02.0
----
-If your device has multiple functions (e.g., ``00:02.0`' and ``00:02.1`'),
-you can pass them through all together with the shortened syntax ``00:02`'
+If your device has multiple functions (e.g., ``00:02.0`' and ``00:02.1`' ),
+you can pass them through all together with the shortened syntax ``00:02`'.
+This is equivalent with checking the ``All Functions`' checkbox in the
+web-interface.
There are some options to which may be necessary, depending on the device
and guest OS:
# qm set VMID -hostpci0 02:00,pcie=on,x-vga=on
----
+.PCI ID overrides
+
+You can override the PCI vendor ID, device ID, and subsystem IDs that will be
+seen by the guest. This is useful if your device is a variant with an ID that
+your guest's drivers don't recognize, but you want to force those drivers to be
+loaded anyway (e.g. if you know your device shares the same chipset as a
+supported variant).
+
+The available options are `vendor-id`, `device-id`, `sub-vendor-id`, and
+`sub-device-id`. You can set any or all of these to override your device's
+default IDs.
+
+For example:
+
+----
+# qm set VMID -hostpci0 02:00,device-id=0x10f6,sub-vendor-id=0x0000
+----
+
Other considerations
^^^^^^^^^^^^^^^^^^^^
Mediated Devices (vGPU, GVT-g)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-Mediated devices are another method to use reuse features and performance from
+Mediated devices are another method to reuse features and performance from
physical hardware for virtualized hardware. These are found most common in
-virtualized GPU setups such as Intels GVT-g and Nvidias vGPUs used in their
+virtualized GPU setups such as Intel's GVT-g and NVIDIA's vGPUs used in their
GRID technology.
With this, a physical Card is able to create virtual cards, similar to SR-IOV.
^^^^^^^^^^^^^^^^^^
In general your card's driver must support that feature, otherwise it will
-not work. So please refer to your vendor for compatbile drivers and how to
+not work. So please refer to your vendor for compatible drivers and how to
configure them.
-Intels drivers for GVT-g are integraded in the Kernel and should work
-with the 5th, 6th and 7th generation Intel Core Processors, further E3 v4, E3
-v5 and E3 v6 Xeon Processors are supported.
+Intel's drivers for GVT-g are integrated in the Kernel and should work
+with 5th, 6th and 7th generation Intel Core Processors, as well as E3 v4, E3
+v5 and E3 v6 Xeon Processors.
-To enable it for Intel Graphcs, you have to make sure to load the module
-'kvmgt' (for example via `/etc/modules`) and to enable it on the Kernel
-commandline. For this you can edit `'/etc/default/grub'' and add the following
-to the 'GRUB_CMDLINE_LINUX_DEFAULT' variable:
+To enable it for Intel Graphics, you have to make sure to load the module
+'kvmgt' (for example via `/etc/modules`) and to enable it on the
+xref:sysboot_edit_kernel_cmdline[Kernel commandline] and add the following parameter:
----
i915.enable_gvt=1
After that remember to
xref:qm_pci_passthrough_update_initramfs[update the `initramfs`],
-xref:qm_pci_passthrough_update_grub[update grub] and
-reboot your host.
+and reboot your host.
VM Configuration
^^^^^^^^^^^^^^^^
With this set, {pve} automatically creates such a device on VM start, and
cleans it up again when the VM stops.
+
+ifdef::wiki[]
+
+See Also
+~~~~~~~~
+
+* link:/wiki/Pci_passthrough[PCI Passthrough Examples]
+
+endif::wiki[]
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