Re: [PATCH 2/2] KVM: MMU: Flush TLBs only once in invlpg() before releasing mmu_lock

[Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>]

On 02/10/2012 02:29 PM, Takuya Yoshikawa wrote:

> diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
> index 1561028..69d06f5 100644
> --- a/arch/x86/kvm/paging_tmpl.h
> +++ b/arch/x86/kvm/paging_tmpl.h
> @@ -682,6 +682,7 @@ static void FNAME(invlpg)(struct kvm_vcpu *vcpu, gva_t gva)
>  	mmu_topup_memory_caches(vcpu);
> 
>  	spin_lock(&vcpu->kvm->mmu_lock);
> +
>  	for_each_shadow_entry(vcpu, gva, iterator) {
>  		level = iterator.level;
>  		sptep = iterator.sptep;
> @@ -697,8 +698,7 @@ static void FNAME(invlpg)(struct kvm_vcpu *vcpu, gva_t gva)
>  			pte_gpa = FNAME(get_level1_sp_gpa)(sp);
>  			pte_gpa += (sptep - sp->spt) * sizeof(pt_element_t);
> 
> -			if (mmu_page_zap_pte(vcpu->kvm, sp, sptep))
> -				kvm_flush_remote_tlbs(vcpu->kvm);
> +			mmu_page_zap_pte(vcpu->kvm, sp, sptep);
> 
>  			if (!rmap_can_add(vcpu))
>  				break;
> @@ -713,6 +713,8 @@ static void FNAME(invlpg)(struct kvm_vcpu *vcpu, gva_t gva)
>  		if (!is_shadow_present_pte(*sptep) || !sp->unsync_children)
>  			break;
>  	}
> +
> +	kvm_flush_remote_tlbs(vcpu->kvm);
>  	spin_unlock(&vcpu->kvm->mmu_lock);


It is obvious wrong, i do not think all tlbs always need be flushed...