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=-10.1 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 CFDBAC433E0 for ; Wed, 3 Mar 2021 12:25:56 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 0DF8564EBA for ; Wed, 3 Mar 2021 12:25:55 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0DF8564EBA Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:45796 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lHQZe-0002HF-VO for qemu-devel@archiver.kernel.org; Wed, 03 Mar 2021 07:25:54 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:36850) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lHQYM-0001hL-7Y for qemu-devel@nongnu.org; Wed, 03 Mar 2021 07:24:34 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:27107) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1lHQYK-0008Iu-Kz for qemu-devel@nongnu.org; Wed, 03 Mar 2021 07:24:33 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1614774271; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=chYU7WqnLFJ21vl7f9w7xry2Yuqgeij98GlbitlpDNk=; b=WmTe+pJ7su08G/tcFMVwA9/0r8KFZ8bSEERC6SPAFlXyar2geWLPOk9ZDnoFyTFS/wIczV 9EuGU6hsyyp7aNRH/PH3RznwP0HQYx//lWdAmw8RxLqCpvYjXBsxqmWnASVKs1khyfAOdR bEGAlVNwbBFwgwZHyHJLMfwCmXNy0Xw= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-143-EdxyWr28PqWJADuF6gFd_w-1; Wed, 03 Mar 2021 07:24:28 -0500 X-MC-Unique: EdxyWr28PqWJADuF6gFd_w-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id EFF4C8017FF; Wed, 3 Mar 2021 12:24:25 +0000 (UTC) Received: from [10.36.112.28] (ovpn-112-28.ams2.redhat.com [10.36.112.28]) by smtp.corp.redhat.com (Postfix) with ESMTP id 8FEB06085D; Wed, 3 Mar 2021 12:24:12 +0000 (UTC) Subject: Re: [PATCH v1 7/9] memory: introduce RAM_NORESERVE and wire it up in qemu_ram_mmap() To: Thomas Huth , Cornelia Huck References: <20210209134939.13083-1-david@redhat.com> <20210209134939.13083-8-david@redhat.com> <20210302173243.GM397383@xz-x1> <91613148-9ade-c192-4b73-0cb5a54ada98@redhat.com> <20210303123517.04729c1e.cohuck@redhat.com> <656d4494-ea36-39c2-2d47-bbb044a67f11@redhat.com> <104f9788-dee2-29ba-5b53-d358f2252cf8@redhat.com> From: David Hildenbrand Organization: Red Hat GmbH Message-ID: <72dd331f-2026-6da9-9089-7c4d1c2ffec8@redhat.com> Date: Wed, 3 Mar 2021 13:24:11 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.8.0 MIME-Version: 1.0 In-Reply-To: <104f9788-dee2-29ba-5b53-d358f2252cf8@redhat.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Received-SPF: pass client-ip=216.205.24.124; envelope-from=david@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, NICE_REPLY_A=-0.001, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Igor Kotrasinski , Eduardo Habkost , kvm@vger.kernel.org, "Michael S. Tsirkin" , qemu-s390x@nongnu.org, Stefan Weil , Murilo Opsfelder Araujo , Richard Henderson , "Dr. David Alan Gilbert" , Peter Xu , qemu-devel@nongnu.org, Halil Pasic , Christian Borntraeger , Greg Kurz , Stefan Hajnoczi , Igor Mammedov , Paolo Bonzini , =?UTF-8?Q?Philippe_Mathieu-Daud=c3=a9?= , Juan Quintela Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 03.03.21 13:12, Thomas Huth wrote: > On 03/03/2021 12.37, David Hildenbrand wrote: >> On 03.03.21 12:35, Cornelia Huck wrote: >>> On Tue, 2 Mar 2021 20:02:34 +0100 >>> David Hildenbrand wrote: >>> >>>> On 02.03.21 18:32, Peter Xu wrote: >>>>> On Tue, Feb 09, 2021 at 02:49:37PM +0100, David Hildenbrand wrote: >>>>>> @@ -899,13 +899,17 @@ int kvm_s390_mem_op_pv(S390CPU *cpu, uint64_t >>>>>> offset, void *hostbuf, >>>>>>     * to grow. We also have to use MAP parameters that avoid >>>>>>     * read-only mapping of guest pages. >>>>>>     */ >>>>>> -static void *legacy_s390_alloc(size_t size, uint64_t *align, bool shared) >>>>>> +static void *legacy_s390_alloc(size_t size, uint64_t *align, bool shared, >>>>>> +                               bool noreserve) >>>>>>    { >>>>>>        static void *mem; >>>>>>        if (mem) { >>>>>>            /* we only support one allocation, which is enough for >>>>>> initial ram */ >>>>>>            return NULL; >>>>>> +    } else if (noreserve) { >>>>>> +        error_report("Skipping reservation of swap space is not >>>>>> supported."); >>>>>> +        return NULL >>>>> >>>>> Semicolon missing. >>>> >>>> Thanks for catching that! >>> >>> Regardless of that (and this patch set), can we finally get rid of >>> legacy_s390_alloc? We already fence off running with a kernel prior to >>> 3.15, and KVM_CAP_S390_COW depends on ESOP -- are non-ESOP kvm hosts >>> still relevant? This seems to be a generation 10 feature; do we >>> realistically expect anyone running this on e.g. a z/VM host that >>> doesn't provide ESOP? >> >> Good question - last time I asked that question (~2 years ago) I was told >> that such z/VM environemnts are still relevant. > > Now that you've mentioned it ... I've even wrote a blog post about z/VM and > ESOP some years ago: > > > http://people.redhat.com/~thuth/blog/qemu/2017/04/05/s390x-selinux-problem.html > > So if I've got that right again, the z/VM ESOP problem only exists on > versions older than 6.3. And according to > https://www.ibm.com/support/lifecycle/search?q=z%2FVM those old versions are > now unsupported since June 2017 ... thus I guess it's valid to assume that > nobody is running such an old z/VM version anymore (at least not to use it > as an environment to run nested KVM guests). Thanks for that info, I'll send a patch proposing to rip it out - that will make things nicer. -- Thanks, David / dhildenb