Richard W.M. Jones wrote:
On Fri, Jun 27, 2008 at 05:56:37PM -0400, Paul Wouters wrote:
Although I was very happy with xen, it seems xen is losing out and kvm is the way to go. I had two migration questions that I couldn't find answers for.
- Does kvm also run with para_virt (eg without VT capable cpu, but also just to be slightly more effecient). virt-manager only gave me a qemu option on my old amd64 cpu.
KVM requires a hardware virt-capable CPU. These are quite common, (if your CPU was made within the last two years or so) but note there are at least two major 'generations' of virt technology in CPUs. In particular very new CPUs from both Intel and AMD support some form of virtualized page tables, which can be very beneficial. Intel describes them here:
http://www.intel.com/technology/itj/2006/v10i3/1-hardware/8-virtualization-f...
[Question: does EPT / NPT only affect 32 bit?]
No, it's applicable to both 32- and 64- bit guests.
The KVM NPT implementation does not work for 32-bit nonpae hosts (it will fall back to not using NPT), so if you have a recent AMD processor and you are using a 32-bit installation, use the pae kernel for best performance.
The kvm NPT and EPT implementations were introduced in Linux 2.6.26.