From mboxrd@z Thu Jan  1 00:00:00 1970
From: Takuya Yoshikawa <takuya.yoshikawa@gmail.com>
Subject: Re: [patch 3/3] KVM: move postcommit flush to x86, as mmio sptes
 are x86 specific
Date: Mon, 27 Aug 2012 23:41:08 +0900
Message-ID: <20120827234108.6f4417e2922e42ef461135c6@gmail.com>
References: <20120824185456.658814016@amt.cnet>
	<20120824185634.625676530@amt.cnet>
Mime-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Cc: Paul Mackerras <paulus@samba.org>, Avi Kivity <avi@redhat.com>,
	Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>,
	kvm@vger.kernel.org
To: Marcelo Tosatti <mtosatti@redhat.com>
Return-path: <kvm-owner@vger.kernel.org>
Received: from mail-pz0-f46.google.com ([209.85.210.46]:40037 "EHLO
	mail-pz0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
	with ESMTP id S1753010Ab2H0OlN (ORCPT <rfc822;kvm@vger.kernel.org>);
	Mon, 27 Aug 2012 10:41:13 -0400
Received: by dady13 with SMTP id y13so2587046dad.19
        for <kvm@vger.kernel.org>; Mon, 27 Aug 2012 07:41:12 -0700 (PDT)
In-Reply-To: <20120824185634.625676530@amt.cnet>
Sender: kvm-owner@vger.kernel.org
List-ID: <kvm.vger.kernel.org>

On Fri, 24 Aug 2012 15:54:59 -0300
Marcelo Tosatti <mtosatti@redhat.com> wrote:

> Other arches do not need this.
> 
> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
> 
> Index: kvm/arch/x86/kvm/x86.c
> ===================================================================
> --- kvm.orig/arch/x86/kvm/x86.c
> +++ kvm/arch/x86/kvm/x86.c
> @@ -6455,6 +6455,14 @@ void kvm_arch_commit_memory_region(struc
>  		kvm_mmu_change_mmu_pages(kvm, nr_mmu_pages);
>  	kvm_mmu_slot_remove_write_access(kvm, mem->slot);
>  	spin_unlock(&kvm->mmu_lock);
> +	/*
> +	 * If the new memory slot is created, we need to clear all
> +	 * mmio sptes.
> +	 */
> +	if (old.npages == 0 && npages) {
> +		kvm_mmu_zap_all(kvm);
> +		kvm_reload_remote_mmus(kvm);
> +	}
>  }

Any explanation why (old.base_gfn != new.base_gfn) case can be
omitted?

Takuya

>  
>  void kvm_arch_flush_shadow_all(struct kvm *kvm)
> Index: kvm/virt/kvm/kvm_main.c
> ===================================================================
> --- kvm.orig/virt/kvm/kvm_main.c
> +++ kvm/virt/kvm/kvm_main.c
> @@ -849,13 +849,6 @@ int __kvm_set_memory_region(struct kvm *
>  
>  	kvm_arch_commit_memory_region(kvm, mem, old, user_alloc);
>  
> -	/*
> -	 * If the new memory slot is created, we need to clear all
> -	 * mmio sptes.
> -	 */
> -	if (npages && old.base_gfn != mem->guest_phys_addr >> PAGE_SHIFT)
> -		kvm_arch_flush_shadow_all(kvm);
> -
>  	kvm_free_physmem_slot(&old, &new);
>  	kfree(old_memslots);