From patchwork Fri Sep 30 14:01:48 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Claudio Imbrenda X-Patchwork-Id: 12995467 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C3317C433FE for ; Fri, 30 Sep 2022 14:02:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231691AbiI3OCJ (ORCPT ); Fri, 30 Sep 2022 10:02:09 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44826 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231378AbiI3OCC (ORCPT ); Fri, 30 Sep 2022 10:02:02 -0400 Received: from mx0a-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DED403120C; Fri, 30 Sep 2022 07:01:59 -0700 (PDT) Received: from pps.filterd (m0098420.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.17.1.5/8.17.1.5) with ESMTP id 28UDrkMm032620; Fri, 30 Sep 2022 14:01:59 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding; s=pp1; bh=jv8GoUS9HkZV3L2RVouc/c06w1GJA5rrLFXbgcVPq4s=; b=JZV9wJVpsxrAwyavzFt0dKD+BHkb7l5rOCUdm5hgR46M+5tFbM31u87PofJ3vCTtA8fw 0jT0oP/91+ZZKyoTBnoeANvwJiwJng/Rf7ArPBaBSVExzeQLyAvojgIaYVf2CLYPa7Ga xQdc2uSmLe8uXt+7jEGWK6Nd8Dhp6q/lM6ca6y/yWGsmNCjBpx+aIZ/ya3K5FCMOfMD/ pspwNc4bijqIIrwLrlx6XiGfYoop82l22W+mRpCsJGjYv2wKuk68uM6722YLRO2v4ebS XzmpE1Gi3AlKbnWHNNf42a+hrrRIlg5uiBZm/i2tCM5YbHV2Prdf1sbn5F7TVNg2V+rt tw== Received: from pps.reinject (localhost [127.0.0.1]) by mx0b-001b2d01.pphosted.com (PPS) with ESMTPS id 3jx1qyg7j9-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 30 Sep 2022 14:01:58 +0000 Received: from m0098420.ppops.net (m0098420.ppops.net [127.0.0.1]) by pps.reinject (8.17.1.5/8.17.1.5) with ESMTP id 28UDrmn3032704; Fri, 30 Sep 2022 14:01:58 GMT Received: from ppma02fra.de.ibm.com (47.49.7a9f.ip4.static.sl-reverse.com [159.122.73.71]) by mx0b-001b2d01.pphosted.com (PPS) with ESMTPS id 3jx1qyg7h2-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 30 Sep 2022 14:01:58 +0000 Received: from pps.filterd (ppma02fra.de.ibm.com [127.0.0.1]) by ppma02fra.de.ibm.com (8.16.1.2/8.16.1.2) with SMTP id 28UDpLZd004831; Fri, 30 Sep 2022 14:01:56 GMT Received: from b06cxnps4075.portsmouth.uk.ibm.com (d06relay12.portsmouth.uk.ibm.com [9.149.109.197]) by ppma02fra.de.ibm.com with ESMTP id 3jssh9658g-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 30 Sep 2022 14:01:56 +0000 Received: from d06av23.portsmouth.uk.ibm.com (d06av23.portsmouth.uk.ibm.com [9.149.105.59]) by b06cxnps4075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 28UE1rfs60031486 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 30 Sep 2022 14:01:53 GMT Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 3D5F4A4040; Fri, 30 Sep 2022 14:01:53 +0000 (GMT) Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id D5D01A4055; Fri, 30 Sep 2022 14:01:52 +0000 (GMT) Received: from p-imbrenda.boeblingen.de.ibm.com (unknown [9.152.224.242]) by d06av23.portsmouth.uk.ibm.com (Postfix) with ESMTP; Fri, 30 Sep 2022 14:01:52 +0000 (GMT) From: Claudio Imbrenda To: kvm@vger.kernel.org Cc: borntraeger@de.ibm.com, frankja@linux.ibm.com, thuth@redhat.com, david@redhat.com, linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, scgl@linux.ibm.com, seiden@linux.ibm.com, nrb@linux.ibm.com Subject: [PATCH v14 4/6] KVM: s390: pv: avoid export before import if possible Date: Fri, 30 Sep 2022 16:01:48 +0200 Message-Id: <20220930140150.37463-5-imbrenda@linux.ibm.com> X-Mailer: git-send-email 2.37.3 In-Reply-To: <20220930140150.37463-1-imbrenda@linux.ibm.com> References: <20220930140150.37463-1-imbrenda@linux.ibm.com> MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-GUID: pgaRPk11HjuvvtE19fWps1RXyHpkzatD X-Proofpoint-ORIG-GUID: on5inOJ271Pj1TSqeOMyw8Yur7mANJwX X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.895,Hydra:6.0.528,FMLib:17.11.122.1 definitions=2022-09-30_04,2022-09-29_03,2022-06-22_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 malwarescore=0 mlxscore=0 suspectscore=0 mlxlogscore=999 phishscore=0 clxscore=1015 impostorscore=0 adultscore=0 priorityscore=1501 bulkscore=0 lowpriorityscore=0 spamscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2209130000 definitions=main-2209300086 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org If the appropriate UV feature bit is set, there is no need to perform an export before import. The misc feature indicates, among other things, that importing a shared page from a different protected VM will automatically also transfer its ownership. Signed-off-by: Claudio Imbrenda Reviewed-by: Nico Boehr Reviewed-by: Janosch Frank Reviewed-by: Steffen Eiden --- arch/s390/kernel/uv.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/arch/s390/kernel/uv.c b/arch/s390/kernel/uv.c index f9810d2a267c..9f18a4af9c13 100644 --- a/arch/s390/kernel/uv.c +++ b/arch/s390/kernel/uv.c @@ -255,6 +255,13 @@ static int make_secure_pte(pte_t *ptep, unsigned long addr, */ static bool should_export_before_import(struct uv_cb_header *uvcb, struct mm_struct *mm) { + /* + * The misc feature indicates, among other things, that importing a + * shared page from a different protected VM will automatically also + * transfer its ownership. + */ + if (test_bit_inv(BIT_UV_FEAT_MISC, &uv_info.uv_feature_indications)) + return false; if (uvcb->cmd == UVC_CMD_UNPIN_PAGE_SHARED) return false; return atomic_read(&mm->context.protected_count) > 1;