From patchwork Tue Jun 2 20:07:28 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Anthony Yznaga X-Patchwork-Id: 11584277 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 5BA0260D for ; Tue, 2 Jun 2020 20:09:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4233A2072F for ; Tue, 2 Jun 2020 20:09:09 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="XxzlY4sx" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728327AbgFBUJC (ORCPT ); Tue, 2 Jun 2020 16:09:02 -0400 Received: from aserp2120.oracle.com ([141.146.126.78]:37812 "EHLO aserp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726130AbgFBUJB (ORCPT ); Tue, 2 Jun 2020 16:09:01 -0400 Received: from pps.filterd (aserp2120.oracle.com [127.0.0.1]) by aserp2120.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 052JulYa168523; Tue, 2 Jun 2020 20:07:42 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=from : to : cc : subject : date : message-id : in-reply-to : references; s=corp-2020-01-29; bh=u/fCzrRFXKu5OAm9GMeH7Ay3Emb8+njH7NIt5wH2t7s=; b=XxzlY4sx0sWv3jxz/jxMxRKHZbtYjTb4uPOXU6PqmOUn1rrF8AWxyLpzLb5NsBW8Bgdo fA4ldu1DD/ctT2BLahOqOvdaZ39DBwyrCyoEXtRkaWLlQQ6TJKHxp9EjJGpzs9qfDHtV wf4RgX3WbfUHm2SLSEc1oATP34jBAPj1ZmqeRbyU8xNV50qps5/GKfuhKLp3zU3RSkNU AuOpo/SDe7PJisvroC4QOLKJld8rCZmqmP8OaX/9bo2X1hJ9EJitun2meX/mpzHVc7+w bpGVYYeYj6pkUCA4OY1SjjJgOi3BpXer8h9HSn9+H/KxUw88Prj9l597+o/5xnHLXzyW wA== Received: from userp3030.oracle.com (userp3030.oracle.com [156.151.31.80]) by aserp2120.oracle.com with ESMTP id 31bfem5uch-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Tue, 02 Jun 2020 20:07:42 +0000 Received: from pps.filterd (userp3030.oracle.com [127.0.0.1]) by userp3030.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 052JxHrQ135232; Tue, 2 Jun 2020 20:07:41 GMT Received: from aserv0121.oracle.com (aserv0121.oracle.com [141.146.126.235]) by userp3030.oracle.com with ESMTP id 31c1dxtrmk-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 02 Jun 2020 20:07:41 +0000 Received: from abhmp0008.oracle.com (abhmp0008.oracle.com [141.146.116.14]) by aserv0121.oracle.com (8.14.4/8.13.8) with ESMTP id 052K7cb2022814; Tue, 2 Jun 2020 20:07:38 GMT Received: from ayz-linux.us.oracle.com (/10.154.185.88) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Tue, 02 Jun 2020 13:07:38 -0700 From: Anthony Yznaga To: kvm@vger.kernel.org, linux-kernel@vger.kernel.org Cc: pbonzini@redhat.com, sean.j.christopherson@intel.com, vkuznets@redhat.com, wanpengli@tencent.com, jmattson@google.com, joro@8bytes.org, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, x86@kernel.org, hpa@zytor.com, steven.sistare@oracle.com, anthony.yznaga@oracle.com Subject: [PATCH 1/3] KVM: x86: remove unnecessary rmap walk of read-only memslots Date: Tue, 2 Jun 2020 13:07:28 -0700 Message-Id: <1591128450-11977-2-git-send-email-anthony.yznaga@oracle.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1591128450-11977-1-git-send-email-anthony.yznaga@oracle.com> References: <1591128450-11977-1-git-send-email-anthony.yznaga@oracle.com> X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9640 signatures=668686 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 phishscore=0 mlxlogscore=999 spamscore=0 bulkscore=0 adultscore=0 suspectscore=0 mlxscore=0 malwarescore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2004280000 definitions=main-2006020146 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9640 signatures=668686 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 malwarescore=0 suspectscore=0 mlxlogscore=999 priorityscore=1501 bulkscore=0 phishscore=0 clxscore=1015 impostorscore=0 adultscore=0 spamscore=0 mlxscore=0 lowpriorityscore=0 cotscore=-2147483648 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2004280000 definitions=main-2006020146 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org There's no write access to remove. An existing memslot cannot be updated to set or clear KVM_MEM_READONLY, and any mappings established in a newly created or moved read-only memslot will already be read-only. Signed-off-by: Anthony Yznaga --- arch/x86/kvm/x86.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index c17e6eb9ad43..23fd888e52ee 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -10038,11 +10038,9 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm, static void kvm_mmu_slot_apply_flags(struct kvm *kvm, struct kvm_memory_slot *new) { - /* Still write protect RO slot */ - if (new->flags & KVM_MEM_READONLY) { - kvm_mmu_slot_remove_write_access(kvm, new, PT_PAGE_TABLE_LEVEL); + /* Nothing to do for RO slots */ + if (new->flags & KVM_MEM_READONLY) return; - } /* * Call kvm_x86_ops dirty logging hooks when they are valid.