Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935570Ab0GPDbN (ORCPT ); Thu, 15 Jul 2010 23:31:13 -0400 Received: from cn.fujitsu.com ([222.73.24.84]:60643 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S935392Ab0GPDbL (ORCPT ); Thu, 15 Jul 2010 23:31:11 -0400 Message-ID: <4C3FD18E.1010908@cn.fujitsu.com> Date: Fri, 16 Jul 2010 11:27:10 +0800 From: Xiao Guangrong User-Agent: Thunderbird 2.0.0.24 (Windows/20100228) MIME-Version: 1.0 To: Avi Kivity CC: Marcelo Tosatti , LKML , KVM list Subject: [PATCH v2 4/6] KVM: MMU: don't atomicly set spte if it's not present References: <4C3FCFD7.5070005@cn.fujitsu.com> <4C3FD11D.1060104@cn.fujitsu.com> In-Reply-To: <4C3FD11D.1060104@cn.fujitsu.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1094 Lines: 34 If the old mapping is not present, the spte.a is not lost, so no need atomic operation to set it Signed-off-by: Xiao Guangrong --- arch/x86/kvm/mmu.c | 5 +++-- 1 files changed, 3 insertions(+), 2 deletions(-) diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index b3896bf..4123e8e 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -307,9 +307,10 @@ static void update_spte(u64 *sptep, u64 new_spte) { u64 old_spte; - if (!shadow_accessed_mask || (new_spte & shadow_accessed_mask)) { + if (!shadow_accessed_mask || (new_spte & shadow_accessed_mask) || + !is_rmap_spte(*sptep)) __set_spte(sptep, new_spte); - } else { + else { old_spte = __xchg_spte(sptep, new_spte); if (old_spte & shadow_accessed_mask) mark_page_accessed(pfn_to_page(spte_to_pfn(old_spte))); -- 1.6.1.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/