[libvirt] [PATCH] cpu_map.xml: Expose svm flag for nested kvm on AMD CPU model

[Jiri Denemark]

On Tue, Jan 19, 2016 at 17:11:36 +0800, Lin Ma wrote:
> QEMU commit 75d373e disables svm by default since PC machine 2.2.
> So with PC machine version > 2.1, When a user wants to expose the
> svm flag to a guest, says:
> 
> ......
>   <feature policy='require' name='svm'/>
> ......
> 
> The svm flag wont be passed to qemu command line, This patch fixes it.
> 
> Signed-off-by: Lin Ma <lma at suse.com>
> ---
>  src/cpu/cpu_map.xml | 6 ------
>  1 file changed, 6 deletions(-)

First of all, I'd like to apologize for forgetting to reply to your
patch when you first sent it. In any case, this is not the right
approach. Since CPU models change with machine types and libvirt has
(and will have) no knowledge what a particular CPU model looks like on a
give machine type, we will probably just need to always pass
policy='require' features to QEMU even though we think they are already
included in the CPU model. I'm starting to work on a bigger change to
our CPU configuration code so that it finally starts doing what it was
supposed to do from the beginning, i.e., to keep guest ABI stable. And
your issue will be also fixed by the changes.

Jirka