Re: [libvirt] [QEMU PATCH] target-i386: Disable rdtscp on Opteron_G* CPU models
On Mon, Nov 16, 2015 at 10:44:59AM +0100, Paolo Bonzini wrote:
On 13/11/2015 20:07, Eduardo Habkost wrote:
> KVM can't virtualize rdtscp on AMD CPUs yet, so there's no point
> in enabling it by default on AMD CPU models, as all we are
> getting are confused users because of the "host doesn't support
> requested feature" warnings.
>
> Disable rdtscp on Opteron_G* models, but keep compatibility on
> pc-*-2.4 and older (just in case there are people are doing funny
> stuff using AMD CPU models on Intel hosts).
>
> Signed-off-by: Eduardo Habkost <ehabkost(a)redhat.com>
Can we do it only on KVM and not on TCG?
We can, but I would like to avoid it, if possible. It would
require more complex compat code (the "Add optional class name to
kvm_default_props¨ patch I sent some time ago), and people who
need rdtscp will be able to use Opteron_G*-rdtscp soon.
--
Eduardo