Linux KVM/Xen support passthrough PCI device. It allows direct assign a PCI device to a virtual machine.
To do this, you need
1. check whether your hardware support VT-d. Here is the list of system that support VT-d.
2. You need to configure and comple the kernel to enable IOMMU support. Here is the procedure to enable VT-d in KVM.
3. Then you should create VM, and assign an PCI device to the VM.
I assigned intel 82571 nic to a VM and find the throughput reaches 930Mb/s easily with very little CPU consumed.
However, I am not quite familiar with the KVM or Xen management. Not quite familiar with bridging mode.
However, you cannot assign PCI device to the VM using libvirt.
Other references:
1. How To Compile A Kernel – The Ubuntu Way.
