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=-5.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no 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 BBE0AC433E0 for ; Tue, 21 Jul 2020 21:38:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 93C532068F for ; Tue, 21 Jul 2020 21:38:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731194AbgGUViG (ORCPT ); Tue, 21 Jul 2020 17:38:06 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:55580 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726658AbgGUViG (ORCPT ); Tue, 21 Jul 2020 17:38:06 -0400 Received: from pps.filterd (m0098409.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 06LLXDjQ176851; Tue, 21 Jul 2020 17:37:47 -0400 Received: from ppma03fra.de.ibm.com (6b.4a.5195.ip4.static.sl-reverse.com [149.81.74.107]) by mx0a-001b2d01.pphosted.com with ESMTP id 32e1yabx0s-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 21 Jul 2020 17:37:47 -0400 Received: from pps.filterd (ppma03fra.de.ibm.com [127.0.0.1]) by ppma03fra.de.ibm.com (8.16.0.42/8.16.0.42) with SMTP id 06LLb3AG026274; Tue, 21 Jul 2020 21:37:45 GMT Received: from b06avi18878370.portsmouth.uk.ibm.com (b06avi18878370.portsmouth.uk.ibm.com [9.149.26.194]) by ppma03fra.de.ibm.com with ESMTP id 32brq826r5-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 21 Jul 2020 21:37:45 +0000 Received: from d06av22.portsmouth.uk.ibm.com (d06av22.portsmouth.uk.ibm.com [9.149.105.58]) by b06avi18878370.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 06LLbg3G64094472 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 21 Jul 2020 21:37:42 GMT Received: from d06av22.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 4B93A4C044; Tue, 21 Jul 2020 21:37:42 +0000 (GMT) Received: from d06av22.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 6E2D84C040; Tue, 21 Jul 2020 21:37:39 +0000 (GMT) Received: from oc0525413822.ibm.com (unknown [9.163.39.1]) by d06av22.portsmouth.uk.ibm.com (Postfix) with ESMTPS; Tue, 21 Jul 2020 21:37:39 +0000 (GMT) Date: Tue, 21 Jul 2020 14:37:36 -0700 From: Ram Pai To: Laurent Dufour Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, kvm-ppc@vger.kernel.org, mpe@ellerman.id.au, paulus@samba.org, sukadev@linux.ibm.com, bauerman@linux.ibm.com, bharata@linux.ibm.com, Paul Mackerras Subject: Re: [PATCH v2 2/2] KVM: PPC: Book3S HV: rework secure mem slot dropping Message-ID: <20200721213736.GG7339@oc0525413822.ibm.com> Reply-To: Ram Pai References: <20200721104202.15727-1-ldufour@linux.ibm.com> <20200721104202.15727-3-ldufour@linux.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200721104202.15727-3-ldufour@linux.ibm.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.235,18.0.687 definitions=2020-07-21_15:2020-07-21,2020-07-21 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 lowpriorityscore=0 suspectscore=0 bulkscore=0 adultscore=0 clxscore=1015 priorityscore=1501 mlxscore=0 mlxlogscore=328 phishscore=0 impostorscore=0 malwarescore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2007210138 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jul 21, 2020 at 12:42:02PM +0200, Laurent Dufour wrote: > When a secure memslot is dropped, all the pages backed in the secure device > (aka really backed by secure memory by the Ultravisor) should be paged out > to a normal page. Previously, this was achieved by triggering the page > fault mechanism which is calling kvmppc_svm_page_out() on each pages. > > This can't work when hot unplugging a memory slot because the memory slot > is flagged as invalid and gfn_to_pfn() is then not trying to access the > page, so the page fault mechanism is not triggered. > > Since the final goal is to make a call to kvmppc_svm_page_out() it seems > simpler to directly calling it instead of triggering such a mechanism. This ^^ call directly instead of triggering.. > way kvmppc_uvmem_drop_pages() can be called even when hot unplugging a > memslot. > > Since kvmppc_uvmem_drop_pages() is already holding kvm->arch.uvmem_lock, > the call to __kvmppc_svm_page_out() is made. > As __kvmppc_svm_page_out needs the vma pointer to migrate the pages, the > VMA is fetched in a lazy way, to not trigger find_vma() all the time. In > addition, the mmap_sem is help in read mode during that time, not in write ^^ held > mode since the virual memory layout is not impacted, and > kvm->arch.uvmem_lock prevents concurrent operation on the secure device. > > Cc: Ram Pai Reviewed-by: Ram Pai RP