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=-0.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS 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 2D0BEC282DD for ; Wed, 8 Jan 2020 15:36:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F264720673 for ; Wed, 8 Jan 2020 15:36:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="YAiEO1C1" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728949AbgAHPgI (ORCPT ); Wed, 8 Jan 2020 10:36:08 -0500 Received: from us-smtp-1.mimecast.com ([205.139.110.61]:48007 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727782AbgAHPgH (ORCPT ); Wed, 8 Jan 2020 10:36:07 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1578497766; 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=6YNW0p309KoXFtpAU4UbagX3xQXhnEerfAmOwO0Imlk=; b=YAiEO1C1cfXAjw65idbOhvA+fjpjQkVFPcOgxquKwSoimh91/shLLfEILXa9w5yaCok7j/ jyPeuWbFkhBym9m12o7AAYcRmx5jTkHbEvpmpDgzq5jeG/Ch/28OVxnZ5dbg0YAma+Uvnw 0+C7bUlYKA4kN7bDhuqbj8DqfOpLY/0= 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-222-GrEnqTf5Mzyw4bp6w9TOqg-1; Wed, 08 Jan 2020 10:36:04 -0500 X-MC-Unique: GrEnqTf5Mzyw4bp6w9TOqg-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 94CB010054E3; Wed, 8 Jan 2020 15:36:03 +0000 (UTC) Received: from gondolin (dhcp-192-245.str.redhat.com [10.33.192.245]) by smtp.corp.redhat.com (Postfix) with ESMTP id A8CC61001938; Wed, 8 Jan 2020 15:36:02 +0000 (UTC) Date: Wed, 8 Jan 2020 16:36:00 +0100 From: Cornelia Huck To: Thomas Huth Cc: Christian Borntraeger , Janosch Frank , kvm@vger.kernel.org, linux-s390@vger.kernel.org Subject: Re: [PATCH v3] KVM: s390: Add new reset vcpu API Message-ID: <20200108163600.54981741.cohuck@redhat.com> In-Reply-To: References: <20191205120956.50930-1-frankja@linux.ibm.com> <3ddb7aa6-96d4-246f-a8ba-fdf2408a4ff0@de.ibm.com> Organization: Red Hat GmbH MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Wed, 8 Jan 2020 15:44:57 +0100 Thomas Huth wrote: > On 08/01/2020 15.38, Christian Borntraeger wrote: > > > > > > On 08.01.20 15:35, Janosch Frank wrote: > >> On 1/8/20 3:28 PM, Christian Borntraeger wrote: > >>> > >>> > >>> On 05.12.19 13:09, Janosch Frank wrote: > >>> [...] > >>>> +4.123 KVM_S390_CLEAR_RESET > >>>> + > >>>> +Capability: KVM_CAP_S390_VCPU_RESETS > >>>> +Architectures: s390 > >>>> +Type: vcpu ioctl > >>>> +Parameters: none > >>>> +Returns: 0 > >>>> + > >>>> +This ioctl resets VCPU registers and control structures that QEMU > >>>> +can't access via the kvm_run structure. The clear reset is a superset > >>>> +of the initial reset and additionally clears general, access, floating > >>>> +and vector registers. > >>> > >>> As Thomas outlined, make it more obvious that userspace does the remaining > >>> parts. I do not think that we want the kernel to do the things (unless it > >>> helps you in some way for the ultravisor guests) > >> > >> Ok, will do > > > > I changed my mind (see my other mail) but I would like Thomas, Conny or David > > to ack/nack. > > I don't mind too much as long as it is properly documented, but I also > slightly prefer to be consistent here, i.e. let the kernel clear the > rest here, too, just like we do it already with the initial reset. I definitely agree with the 'properly documented' part :) It's probably enough to just state that the kernel resets the stuff, no need to go into details (and we also don't need to update this for later versions.) Q: Are we sure that we will always be able to reset everything from the kernel?