From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, UNPARSEABLE_RELAY,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3FE49C43463 for ; Thu, 17 Sep 2020 21:25:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0B68F208E4 for ; Thu, 17 Sep 2020 21:25:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="dWc+A2Ue" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726221AbgIQVZR (ORCPT ); Thu, 17 Sep 2020 17:25:17 -0400 Received: from aserp2120.oracle.com ([141.146.126.78]:33404 "EHLO aserp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725858AbgIQVZP (ORCPT ); Thu, 17 Sep 2020 17:25:15 -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 08HLEuaa012382; Thu, 17 Sep 2020 21:22:33 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=3eJ0X/nkHtps0s17VeY8/THZYuT416x78/To7uTXJRs=; b=dWc+A2UeJjT8CBTBhcUyYOpcm9ctECAJCMHTGbdWW0SecjEghfjSELijW/7fDQy79Lj5 jFfVxGD/DTb9GjZcVCcxh03lQ+avFocdH8VitgIHYiItwFCjT/VUZCUhHnQL6+cQ24A+ 4KLnRfC+F8zvwgYoFIop+wlndwQG6YIjeS95dU63W9qp9LZkd05tBGGh05uILRgmszT4 KR8erff3zt4OEyxAR/TAK0DgY4h+airDe2lN35PyUDCdryrGeh8sY+EcQCgD5I9cmncT InYKCfgfHgCmyhhYc3XtEcyYXySnAsNYxJWIZzm5ImZHh5+hqk3SchWHpy6BhQ9WqLTI Pg== Received: from userp3020.oracle.com (userp3020.oracle.com [156.151.31.79]) by aserp2120.oracle.com with ESMTP id 33gp9mku7g-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Thu, 17 Sep 2020 21:22:32 +0000 Received: from pps.filterd (userp3020.oracle.com [127.0.0.1]) by userp3020.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 08HL9uEE148201; Thu, 17 Sep 2020 21:22:32 GMT Received: from userv0121.oracle.com (userv0121.oracle.com [156.151.31.72]) by userp3020.oracle.com with ESMTP id 33hm35k152-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 17 Sep 2020 21:22:32 +0000 Received: from abhmp0013.oracle.com (abhmp0013.oracle.com [141.146.116.19]) by userv0121.oracle.com (8.14.4/8.13.8) with ESMTP id 08HLMSwF026929; Thu, 17 Sep 2020 21:22:28 GMT Received: from nsvm-sadhukhan-1.osdevelopmeniad.oraclevcn.com (/100.100.230.216) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Thu, 17 Sep 2020 21:22:28 +0000 From: Krish Sadhukhan To: kvm@vger.kernel.org Cc: pbonzini@redhat.com, jmattson@google.com, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, x86@kernel.org, sean.j.christopherson@intel.com, vkuznets@redhat.com, wanpengli@tencent.com, joro@8bytes.org, dave.hansen@linux.intel.com, luto@kernel.org, peterz@infradead.org, linux-kernel@vger.kernel.org, hpa@zytor.com Subject: [PATCH 3/3 v4] KVM: SVM: Don't flush cache if hardware enforces cache coherency across encryption domains Date: Thu, 17 Sep 2020 21:20:38 +0000 Message-Id: <20200917212038.5090-4-krish.sadhukhan@oracle.com> X-Mailer: git-send-email 2.18.4 In-Reply-To: <20200917212038.5090-1-krish.sadhukhan@oracle.com> References: <20200917212038.5090-1-krish.sadhukhan@oracle.com> X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9747 signatures=668679 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 spamscore=0 bulkscore=0 mlxlogscore=808 malwarescore=0 mlxscore=0 phishscore=0 adultscore=0 suspectscore=1 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2009170158 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9747 signatures=668679 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 bulkscore=0 mlxlogscore=823 adultscore=0 malwarescore=0 clxscore=1015 lowpriorityscore=0 phishscore=0 spamscore=0 priorityscore=1501 suspectscore=1 impostorscore=0 mlxscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2009170158 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In some hardware implementations, coherency between the encrypted and unencrypted mappings of the same physical page in a VM is enforced. In such a system, it is not required for software to flush the VM's page from all CPU caches in the system prior to changing the value of the C-bit for the page. Signed-off-by: Krish Sadhukhan --- arch/x86/kvm/svm/sev.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c index 7bf7bf734979..3c9a45efdd4d 100644 --- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -384,7 +384,8 @@ static void sev_clflush_pages(struct page *pages[], unsigned long npages) uint8_t *page_virtual; unsigned long i; - if (npages == 0 || pages == NULL) + if (this_cpu_has(X86_FEATURE_SME_COHERENT) || npages == 0 || + pages == NULL) return; for (i = 0; i < npages; i++) { -- 2.18.4