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=-12.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,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 BD432C432C3 for ; Mon, 4 Jan 2021 16:09:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 99C11205CA for ; Mon, 4 Jan 2021 16:09:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726300AbhADQJt (ORCPT ); Mon, 4 Jan 2021 11:09:49 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:57234 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727525AbhADQJt (ORCPT ); Mon, 4 Jan 2021 11:09:49 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1609776503; 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=iCAALDuWRacu50XtT51NThRS2gMEi63ytyilijXxcII=; b=jSNM5EbXOg8GPmoT3sOy6nmW15d19VDct2yZucTXeC3s/v9+HK6kLjU6+8QMGXdp5K23my jERgtJZZo8m0IKdzEgS6faJNWqrqQ2usQAsnHs+ejJJvL4Yc0dZksnbn1+eTJvEa2joLji dmkm5FttVBMv8xYqw4bkaFs8S98ZgrE= 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-581-1_pgLx88Nra8cXTYwW6CHg-1; Mon, 04 Jan 2021 11:08:19 -0500 X-MC-Unique: 1_pgLx88Nra8cXTYwW6CHg-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 23A73BBEEB; Mon, 4 Jan 2021 16:08:18 +0000 (UTC) Received: from [10.36.114.59] (ovpn-114-59.ams2.redhat.com [10.36.114.59]) by smtp.corp.redhat.com (Postfix) with ESMTP id B9AC771C93; Mon, 4 Jan 2021 16:08:16 +0000 (UTC) Subject: Re: [PATCH v1 4/4] s390/kvm: VSIE: correctly handle MVPG when in VSIE To: Claudio Imbrenda Cc: linux-kernel@vger.kernel.org, borntraeger@de.ibm.com, frankja@linux.ibm.com, kvm@vger.kernel.org, linux-s390@vger.kernel.org, stable@vger.kernel.org References: <20201218141811.310267-1-imbrenda@linux.ibm.com> <20201218141811.310267-5-imbrenda@linux.ibm.com> <6836573a-a49d-9d9f-49e0-96b5aa479c52@redhat.com> <20210104162231.4e56ab47@ibm-vm> From: David Hildenbrand Organization: Red Hat GmbH Message-ID: <3376268b-7fd7-9fbe-b483-fe7471038a18@redhat.com> Date: Mon, 4 Jan 2021 17:08:15 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.5.0 MIME-Version: 1.0 In-Reply-To: <20210104162231.4e56ab47@ibm-vm> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org On 04.01.21 16:22, Claudio Imbrenda wrote: > On Sun, 20 Dec 2020 11:13:57 +0100 > David Hildenbrand wrote: > >> On 18.12.20 15:18, Claudio Imbrenda wrote: >>> Correctly handle the MVPG instruction when issued by a VSIE guest. >>> >> >> I remember that MVPG SIE documentation was completely crazy and full >> of corner cases. :) > > you remember correctly > >> Looking at arch/s390/kvm/intercept.c:handle_mvpg_pei(), I can spot >> that >> >> 1. "This interception can only happen for guests with DAT disabled >> ..." 2. KVM does not make use of any mvpg state inside the SCB. >> >> Can this be observed with Linux guests? > > a Linux guest will typically not run with DAT disabled > >> Can I get some information on what information is stored at [0xc0, >> 0xd) inside the SCB? I assume it's: >> >> 0xc0: guest physical address of source PTE >> 0xc8: guest physical address of target PTE > > yes (plus 3 flags in the lower bits of each) Thanks! Do the flags tell us what the deal with the PTE was? If yes, what's the meaning of the separate flags? I assume something like "invalid, proteced, ??" I'm asking because I think we can handle this a little easier. > >> [...] >>> /* >>> * Run the vsie on a shadow scb and a shadow gmap, without any >>> further >>> * sanity checks, handling SIE faults. >>> @@ -1063,6 +1132,10 @@ static int do_vsie_run(struct kvm_vcpu >>> *vcpu, struct vsie_page *vsie_page) if ((scb_s->ipa & 0xf000) != >>> 0xf000) scb_s->ipa += 0x1000; >>> break; >>> + case ICPT_PARTEXEC: >>> + if (scb_s->ipa == 0xb254) >> >> Old code hat "/* MVPG only */" - why is this condition now necessary? > > old code was wrong ;) arch/s390/kvm/intercept.c:handle_partial_execution() we only seem to handle 1. MVPG 2. SIGP PEI The latter is only relevant for external calls. IIRC, this is only active with sigp interpretation - which is never active under vsie (ECA_SIGPI). -- Thanks, David / dhildenb