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38 lines
1.2 KiB
Markdown
38 lines
1.2 KiB
Markdown
---
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layout: wiki
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title: AssigningDevices
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permalink: /wiki/AssigningDevices/
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---
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In order to assign a whole PCI/e device to a VM one should use ```qvm-pci``` tool. E.g.
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``` {.wiki}
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lspci
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```
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Find the BDF address of the device you want to assign, and then:
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``` {.wiki}
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qvm-pci -a <vmname> <bdf>
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```
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E.g. assuming 00:1a.0 is a BDF of the device I want to assign to "personal" domain:
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``` {.wiki}
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qvm-pci -a personal 00:1a.0
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```
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Note that one can only assign full PCI or PCI Express devices. This means one cannot assign single USB devices -- only the whole USB controller with whatever USB devices connected to it. This limit is imposed by PC and VT-d architecture.
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### Possible issues
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VM with PCI device in Qubes have allocated small buffer for DMA operations (called swiotlb). By default it is 2MB, but some devices needs a larger space. To change this allocation, edit VM kernel parameters (this is expressed in 512B chunks):
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``` {.wiki}
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# qvm-prefs netvm |grep kernelopts
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kernelopts : iommu=soft swiotlb=2048 (default)
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# qvm-prefs -s netvm kernelopts "iommu=soft swiotlb=4096"
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```
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This is [know to be needed](https://groups.google.com/group/qubes-devel/browse_thread/thread/631c4a3a9d1186e3) for Realtek RTL8111DL Gigabit Ethernet Controller.
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