[Fedora-xen] xen to kvm migration question
Avi Kivity
avi at qumranet.com
Sun Jun 29 13:54:53 UTC 2008
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.
>>
>> 1) 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-future.htm
>
> [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.
--
error compiling committee.c: too many arguments to function
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