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 847D2C47254 for ; Tue, 5 May 2020 08:33:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5A19320658 for ; Tue, 5 May 2020 08:33:30 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="NSbRp6K1" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728488AbgEEId3 (ORCPT ); Tue, 5 May 2020 04:33:29 -0400 Received: from us-smtp-1.mimecast.com ([207.211.31.81]:35576 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727784AbgEEId3 (ORCPT ); Tue, 5 May 2020 04:33:29 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1588667608; 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=cxZ3uZ0zoCJmHZiRVgV/TlO2GfBb/WBpAElEsKGOLxs=; b=NSbRp6K1rzkE7dYUxmLC8o2GnjMMJU8TmhQ/GiQAs3e8hOB2ZPSAAimAvKDQjWmGqGgQ29 YiUvxD5wYgw0u0Q4zzL9rsMAfBe2hKplzXN32TNgXLZ7LP+lpxgKE0YS+TbYHiF629Su9f gTPbk+8v2IIMfEDfTVbcoIS8Mdl609U= 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-415-Uh8ED_ZoORuyA8xJ0qPdig-1; Tue, 05 May 2020 04:33:26 -0400 X-MC-Unique: Uh8ED_ZoORuyA8xJ0qPdig-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 40C2E800687; Tue, 5 May 2020 08:33:25 +0000 (UTC) Received: from gondolin (ovpn-112-219.ams2.redhat.com [10.36.112.219]) by smtp.corp.redhat.com (Postfix) with ESMTP id E1B8A600F5; Tue, 5 May 2020 08:33:20 +0000 (UTC) Date: Tue, 5 May 2020 10:33:19 +0200 From: Cornelia Huck To: Christian Borntraeger Cc: David Hildenbrand , Janosch Frank , KVM , linux-s390 , Qian Cai , Pierre Morel , Tony Krowiak Subject: Re: [PATCH] KVM: s390: Remove false WARN_ON_ONCE for the PQAP instruction Message-ID: <20200505103145.1057c2a3.cohuck@redhat.com> In-Reply-To: <480b0bff-8eb5-f75c-a3ce-2555e38917ee@de.ibm.com> References: <20200505073525.2287-1-borntraeger@de.ibm.com> <20200505095332.528254e5.cohuck@redhat.com> <59f1b90c-47d6-2661-0e99-548a53c9bcd6@redhat.com> <480b0bff-8eb5-f75c-a3ce-2555e38917ee@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 2.79 on 10.5.11.11 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Tue, 5 May 2020 10:27:16 +0200 Christian Borntraeger wrote: > On 05.05.20 10:04, David Hildenbrand wrote: > > On 05.05.20 09:55, Christian Borntraeger wrote: > >> > >> > >> On 05.05.20 09:53, Cornelia Huck wrote: > >>> On Tue, 5 May 2020 09:35:25 +0200 > >>> Christian Borntraeger wrote: > >>> > >>>> In LPAR we will only get an intercept for FC==3 for the PQAP > >>>> instruction. Running nested under z/VM can result in other intercepts as > >>>> well, for example PQAP(QCI). So the WARN_ON_ONCE is not right. Let > >>>> us simply remove it. > >>> > >>> While I agree with removing the WARN_ON_ONCE, I'm wondering why z/VM > >>> gives us intercepts for those fcs... is that just a result of nesting > >>> (or the z/VM implementation), or is there anything we might want to do? > >> > >> Yes nesting. > >> The ECA bit for interpretion is an effective one. So if the ECA bit is off > >> in z/VM (no crypto cards) our ECA bit is basically ignored as these bits > >> are ANDed. > >> I asked Tony to ask the z/VM team if that is the case here. > >> > > > > So we can't detect if we have support for ECA_APIE, because there is no > > explicit feature bit, right? Rings a bell. Still an ugly > > hardware/firmware specification. > > Yes, no matter if this is the case here, we cannot rely on ECA_APIE to not > trigger intercepts. So we must remove the WARN_ON. > > cc stable? Agreed. > > > > > Seems to be the right thing to do > > > > Reviewed-by: David Hildenbrand > > >