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[2620:137:e000::1:20]) by mx.google.com with ESMTP id b21-20020a170902d31500b0016a28448c46si25014438plc.561.2022.06.30.08.55.46; Thu, 30 Jun 2022 08:55:46 -0700 (PDT) Received-SPF: pass (google.com: domain of kvm-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@redhat.com header.s=mimecast20190719 header.b=B6UCXX1D; spf=pass (google.com: domain of kvm-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=kvm-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235985AbiF3Pzp (ORCPT + 3 others); Thu, 30 Jun 2022 11:55:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35304 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236232AbiF3Pzo (ORCPT ); Thu, 30 Jun 2022 11:55:44 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 6B0CD39817 for ; Thu, 30 Jun 2022 08:55:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1656604542; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=nRvPip85gUSbUJnsZ8cTFSvmkrYw0M7WomwTPU0jwws=; b=B6UCXX1D+JLJUnyIbQHkPxuW1SZIeB7PA/OkmpdIB8aWQNiHSrSMYGB2JoVeyGTXgNGDtt SYQub5N5xP7Nf5wgcuAiwx680NdQD5eQXGI2/VFagqW2ZA4PtHepzAzjRpzp4rROz5GRWk R29fRoll4WRXrC+zFHoH/orHhI3JJ9s= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-357-zHtl7fHHORa_8sUJbxyC8g-1; Thu, 30 Jun 2022 11:55:40 -0400 X-MC-Unique: zHtl7fHHORa_8sUJbxyC8g-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id F03D42919ECB; Thu, 30 Jun 2022 15:55:39 +0000 (UTC) Received: from localhost (unknown [10.39.195.64]) by smtp.corp.redhat.com (Postfix) with ESMTPS id A2F702166B26; Thu, 30 Jun 2022 15:55:39 +0000 (UTC) From: Cornelia Huck To: Eric Auger , Peter Maydell , Thomas Huth , Laurent Vivier Cc: Andrew Jones , qemu-arm@nongnu.org, qemu-devel@nongnu.org, kvm@vger.kernel.org Subject: Re: [PATCH RFC 1/2] arm/kvm: enable MTE if available In-Reply-To: <9dfbfd42-6a40-80d2-8d9d-f5849de0b726@redhat.com> Organization: Red Hat GmbH References: <20220512131146.78457-1-cohuck@redhat.com> <20220512131146.78457-2-cohuck@redhat.com> <877d5jskmw.fsf@redhat.com> <9dfbfd42-6a40-80d2-8d9d-f5849de0b726@redhat.com> User-Agent: Notmuch/0.36 (https://notmuchmail.org) Date: Thu, 30 Jun 2022 17:55:38 +0200 Message-ID: <87o7ya2lj9.fsf@redhat.com> MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 2.78 on 10.11.54.6 X-Spam-Status: No, score=-3.2 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_LOW, SPF_HELO_NONE,SPF_NONE,T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-TUID: muAcKkbtq856 On Wed, Jun 29 2022, Eric Auger wrote: > Hi Connie, > > On 6/14/22 10:40, Cornelia Huck wrote: >> On Fri, Jun 10 2022, Eric Auger wrote: >> >>> Hi Connie, >>> On 5/12/22 15:11, Cornelia Huck wrote: >>>> We need to disable migration, as we do not yet have a way to migrate >>>> the tags as well. >>> >>> This patch does much more than adding a migration blocker ;-) you may >>> describe the new cpu option and how it works. >> >> I admit this is a bit terse ;) The idea is to control mte at the cpu >> level directly (and not indirectly via tag memory at the machine >> level). I.e. the user gets whatever is available given the constraints >> (host support etc.) if they don't specify anything, and they can >> explicitly turn it off/on. > > Could the OnOffAuto property value be helpful? I completely forgot that this exists; I hacked up something (still untested), and it seems to be able to do what I want. I'll post it after I've verified that it actually works :) >> The big elefant in the room is how migration will end up >> working... after reading the disscussions in >> https://lore.kernel.org/all/CAJc+Z1FZxSYB_zJit4+0uTR-88VqQL+-01XNMSEfua-dXDy6Wg@mail.gmail.com/ >> I don't think it will be as "easy" as I thought, and we probably require >> some further fiddling on the kernel side. > Yes maybe the MTE migration process shall be documented and discussed > separately on the ML? Is Haibu Xu's address bouncing? Yes, that address is bouncing... I've piggybacked onto a recent kvm discussion in https://lore.kernel.org/all/875ykmcd8q.fsf@redhat.com/ -- I guess there had not been any change for migration in the meantime, we need to find a way to tie page data + metadata together.