Re: [PATCH RFC v2 6/6] KVM: introduce a new API for getting dirty bitmaps

Alexander Graf
2010-04-20T11:15:06Z

On 20.04.2010, at 13:03, Takuya Yoshikawa wrote:

> We can now export the addree of the bitmap created by do_mmap()
> to user space. For the sake of this, we introduce a new API:
>
> KVM_SWITCH_DIRTY_LOG: application can use this to trigger the
> switch of the bitmaps and get the address of the bitmap which
> has been used until now. This reduces the copy of the dirty
> bitmap from the kernel.
>
> Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
> Cc: Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
> ---
> Documentation/kvm/api.txt | 23 +++++++++++++++++++++++
> arch/ia64/kvm/kvm-ia64.c | 19 ++++++++++++++-----
> arch/powerpc/kvm/book3s.c | 19 ++++++++++++++-----
> arch/x86/kvm/x86.c | 32 ++++++++++++++++++++++++++------
> include/linux/kvm.h | 6 ++++--
> include/linux/kvm_host.h | 7 ++++---
> virt/kvm/kvm_main.c | 41 ++++++++++++++++++++++++++++++++++++-----
> 7 files changed, 121 insertions(+), 26 deletions(-)
>

[...]

> diff --git a/include/linux/kvm.h b/include/linux/kvm.h
> index 23ea022..9fa6f1e 100644
> --- a/include/linux/kvm.h
> +++ b/include/linux/kvm.h
> @@ -12,7 +12,7 @@
> #include <linux/ioctl.h>
> #include <asm/kvm.h>
>
> -#define KVM_API_VERSION 12
> +#define KVM_API_VERSION 13

Is there a way to keep both interfaces around for some time at least? I'd prefer the API version not to change if not _really_ necessary.

To enable the new dirty mapping you could for example use KVM_CAP_ENABLE_CAP :-).

Alex