Re: [PATCH/RFC] KVM: Plan obsolescence of kernel allocated slots, paravirt mmu

[Marcelo Tosatti <mtosatti@redhat.com>]

On Tue, Jan 26, 2010 at 04:34:34PM +0200, Avi Kivity wrote:
> These features are unused by modern userspace and can go away.  Paravirt
> mmu needs to stay a little longer for live migration.
> 
> Signed-off-by: Avi Kivity <avi@redhat.com>
> ---
>  Documentation/feature-removal-schedule.txt |   23 +++++++++++++++++++++++
>  1 files changed, 23 insertions(+), 0 deletions(-)
> 
> diff --git a/Documentation/feature-removal-schedule.txt b/Documentation/feature-removal-schedule.txt
> index 870d190..88ca110 100644
> --- a/Documentation/feature-removal-schedule.txt
> +++ b/Documentation/feature-removal-schedule.txt
> @@ -493,3 +493,26 @@ Why:	These two features use non-standard interfaces. There are the
>  Who:	Corentin Chary <corentin.chary@gmail.com>
>  
>  ----------------------------
> +What:	KVM memory aliases support
> +When:	July 2010
> +Why:	Memory aliasing support is used for speeding up guest vga access
> +	through the vga windows.
> +
> +	Modern userspace no longer uses this feature, so it's just bitrotted
> +	code and can be removed with no impact.
> +Who:	Avi Kivity <avi@redhat.com>
> +----------------------------
> +What:	KVM kernel-allocated memory slots
> +When:	July 2010
> +Why:	Since 2.6.25, kvm supports user-allocated memory slots, which are
> +	much more flexible than kernel-allocated slots.  All current userspace
> +	supports the newer interface and this code can be removed with no
> +	impact.

Just a note: can block userspace usage but can't really remove code
since there are in-kernel users (special purpose vmx pages).

Otherwise looks good to me.

> +Who:	Avi Kivity <avi@redhat.com>
> +----------------------------
> +What:	KVM paravirt mmu host support
> +When:	January 2011
> +Why:	The paravirt mmu host support is slower than non-paravirt mmu, both
> +	on newer and older hardware.  It is already not exposed to the guest,
> +	and kept only for live migration purposes.
> +Who:	Avi Kivity <avi@redhat.com>
> -- 
> 1.6.5.3
> 
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