Re: [PATCH] kvm mmu: optimizations when tdp is in use

[Avi Kivity <avi@redhat.com>]

On 05/27/2010 11:06 AM, Gui Jianfeng wrote:
> In case of using tdp, checking write protected page isn't needed and
> quadrant also no need to be calculated.
>
> Signed-off-by: Gui Jianfeng<guijianfeng@cn.fujitsu.com>
> ---
>   arch/x86/kvm/mmu.c |    7 +++++--
>   1 files changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
> index 0bb9f17..ce4bbd3 100644
> --- a/arch/x86/kvm/mmu.c
> +++ b/arch/x86/kvm/mmu.c
> @@ -495,10 +495,13 @@ static int mapping_level(struct kvm_vcpu *vcpu, gfn_t large_gfn)
>   	max_level = kvm_x86_ops->get_lpage_level()<  host_level ?
>   		kvm_x86_ops->get_lpage_level() : host_level;
>
> +	if (tdp_enabled)
> +		goto done;
> +
>   	for (level = PT_DIRECTORY_LEVEL; level<= max_level; ++level)
>   		if (has_wrprotected_page(vcpu->kvm, large_gfn, level))
>   			break;
> -
> +done:
>   	return level - 1;
>   }
>
>    

We also use ->write_count to prevent mapping the end of a 
non-large-page-aligned memslot with a large spte.

Undocumented in mmu.txt, I'll post a patch.

-- 
error compiling committee.c: too many arguments to function