From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:32030 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728810AbfKDOcl (ORCPT ); Mon, 4 Nov 2019 09:32:41 -0500 Subject: Re: [RFC v2] KVM: s390: protvirt: Secure memory is not mergeable References: <20191024114059.102802-8-frankja@linux.ibm.com> <20191025082446.754-1-frankja@linux.ibm.com> From: David Hildenbrand Message-ID: <7918ea28-8f10-dc1c-e35b-c1b66631877e@redhat.com> Date: Mon, 4 Nov 2019 15:32:25 +0100 MIME-Version: 1.0 In-Reply-To: <20191025082446.754-1-frankja@linux.ibm.com> Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: quoted-printable Sender: linux-s390-owner@vger.kernel.org List-ID: To: Janosch Frank , kvm@vger.kernel.org Cc: linux-s390@vger.kernel.org, thuth@redhat.com, borntraeger@de.ibm.com, imbrenda@linux.ibm.com, mihajlov@linux.ibm.com, mimu@linux.ibm.com, cohuck@redhat.com, gor@linux.ibm.com On 25.10.19 10:24, Janosch Frank wrote: > KSM will not work on secure pages, because when the kernel reads a > secure page, it will be encrypted and hence no two pages will look the > same. >=20 > Let's mark the guest pages as unmergeable when we transition to secure > mode. Patch itself looks good to me, but I do wonder: Is this really needed=20 when pinning all encrypted pages currently? Not sure about races between KSM and the pinning/encrypting thread,=20 similar to paging, though ... --=20 Thanks, David / dhildenb