Re: [PATCH/RFC] kvm/powerpc: Add new ioctl to retreive support page sizes and encodings

[Avi Kivity <avi@redhat.com>]

On 03/16/2012 09:55 AM, Benjamin Herrenschmidt wrote:
> This is necessary for qemu to be able to pass the right information
> to the guest, as the supported sizes and encodings can vary depending
> on the machine, the type of KVM used (PR vs HV) and the version of KVM
>
> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> ---
>
> Please comment ASAP. I'm tired of the qemu side never working properly
> because of that and our out-of-tree nasty patches we've been carrying
> internally, so I'd like to get something like that in real quick :-)
>
> I have the qemu side patches that use this to generate the appropriate
> device-tree when available, and use heuristics for the fallback. I'll
> post them later, let's agree on the kernel interfaces first.
>
> The heuristics work as long as we have a reasonable guarantee that this
> kernel patch will get in -before- any patch that enables the PVINFO
> ioctl on "HV" KVM, that way I can rely on the later not working as
> a way to differenciate PR and HV KVM if this new ioctl is not supported. 
>
> Note: We probably want an other ioctl for getting other type of
> MMU info, such as whether we support 1T segments etc... but I didn't
> want to try to kill to many birds at once and end up in bike shed
> painting on the mailing list for the next 6 month...
>
> Cheers,
> Ben.
>
>  arch/powerpc/include/asm/kvm_ppc.h |    3 ++-
>  arch/powerpc/kvm/book3s_hv.c       |   35 +++++++++++++++++++++++++++++++++++
>  arch/powerpc/kvm/book3s_pr.c       |   22 ++++++++++++++++++++++
>  arch/powerpc/kvm/powerpc.c         |   18 +++++++++++++++++-
>  include/linux/kvm.h                |   29 +++++++++++++++++++++++++++++
>  5 files changed, 105 insertions(+), 2 deletions(-)
>

-ENODOCS

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