Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753172AbcCGORg (ORCPT ); Mon, 7 Mar 2016 09:17:36 -0500 Received: from mail-wm0-f65.google.com ([74.125.82.65]:33201 "EHLO mail-wm0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752886AbcCGOQL (ORCPT ); Mon, 7 Mar 2016 09:16:11 -0500 From: Paolo Bonzini To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: Takuya Yoshikawa , Xiao Guangrong Subject: [PATCH 9/9] KVM: MMU: micro-optimize gpte_access Date: Mon, 7 Mar 2016 15:15:55 +0100 Message-Id: <1457360155-9610-11-git-send-email-pbonzini@redhat.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1457360155-9610-1-git-send-email-pbonzini@redhat.com> References: <1457360155-9610-1-git-send-email-pbonzini@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 975 Lines: 27 Avoid AND-NOT, most x86 processor lack an instruction for it. Signed-off-by: Paolo Bonzini --- arch/x86/kvm/paging_tmpl.h | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h index a1f5459edcec..6013f3685ef4 100644 --- a/arch/x86/kvm/paging_tmpl.h +++ b/arch/x86/kvm/paging_tmpl.h @@ -189,8 +189,11 @@ static inline unsigned FNAME(gpte_access)(struct kvm_vcpu *vcpu, u64 gpte) ((gpte & VMX_EPT_EXECUTABLE_MASK) ? ACC_EXEC_MASK : 0) | ACC_USER_MASK; #else - access = (gpte & (PT_WRITABLE_MASK | PT_USER_MASK)) | ACC_EXEC_MASK; - access &= ~(gpte >> PT64_NX_SHIFT); + BUILD_BUG_ON(ACC_EXEC_MASK != PT_PRESENT_MASK); + BUILD_BUG_ON(ACC_EXEC_MASK != 1); + access = gpte & (PT_WRITABLE_MASK | PT_USER_MASK | PT_PRESENT_MASK); + /* Combine NX with P (which is set here) to get ACC_EXEC_MASK. */ + access ^= (gpte >> PT64_NX_SHIFT); #endif return access; -- 1.8.3.1