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I am trying to passthrough a graphics card to a KVM guest but have been unsuccessful.

The graphics cards has been attached and it does appear that the guest is aware of the card, I can see the kernel module has been loaded when I do lsmod.

Also I did notice that both the host and guest are loading the kernel modules for the graphics card. I have attempted to disable the host from loading the driver via the blacklist in /etc/modprobe.d but to no avail.

System specs are as below: - Centos 6.5 - i5-4460 CPU - H97M-D3H Motherboard - 2x Gigabyte 5450 PCI-E Graphics Card

I have enabled VT-x/VT-d and enabled iommu by adding "intel_iommu=on" the grub config file. Additionally, I have enable allow_unsafe_assigned_interrupts=1.

I understand there are later versions of the kernel that does a better job of passing through graphics card using vfio-pci. However, I would prefer using the upstream kernel that comes with CentOS at this stage.

If anyone can point me in the right direction, that'll be greatly appreciated. Thank you.

  • Have you followed the steps at: linux-kvm.org/page/How_to_assign_devices_with_VT-d_in_KVM ? – Brian Sep 11 '14 at 14:57
  • Yes, I pretty much did the same thing. Checked VT-d/VT-x, enabled DMAR and allow unsafe assigned interupts. However, I attached the PCI devices via the virt-manager instead. It still results in the same thing, XML file gets generated and devices get attached to the pci-stub. – supmethods Sep 11 '14 at 15:20
  • Decided to upgrade to kernel 3.10 via the elrepo. Doesn't have vfio_vga enabled by default though. Guess I'll end up having to compile the kernel module after all. – supmethods Sep 11 '14 at 15:58
  • Ok, I've compiled the kernel with vfio-pci. Module has been loaded and graphic cards has been binded successfully. However, when I'm trying to do a test run with /usr/libexec/qemu-kvm, I can't see the option to use vfio-pci. Am I missing something here? – supmethods Sep 26 '14 at 16:07
  • From digging around Google, it's seem I'll need to compile QEMU for support vfio. However, I would prefer to use QEMU-KVM but I'm uncertain whether it supports vfio. I can't seem to find any patch for vfio from the source RPM on CentOS repository (qemu-kvm-0.12.1.2-2.415.el6_5.14.src.rpm). – supmethods Oct 13 '14 at 13:23

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