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=-3.5 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 883B0C2D0F7 for ; Tue, 12 May 2020 16:06:49 +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 5195E20736 for ; Tue, 12 May 2020 16:06:49 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="MD8NIFAO" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5195E20736 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]:41398 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jYXQe-0007iH-F3 for qemu-devel@archiver.kernel.org; Tue, 12 May 2020 12:06:48 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:43850) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jYXM2-0002Bg-Sw for qemu-devel@nongnu.org; Tue, 12 May 2020 12:02:02 -0400 Received: from us-smtp-2.mimecast.com ([207.211.31.81]:37648 helo=us-smtp-delivery-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1jYXM2-00042b-5s for qemu-devel@nongnu.org; Tue, 12 May 2020 12:02:02 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1589299321; 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=B/HfK/1p3woSs1jS9R6Yo/SO4WZfYrwj5AAotzzd/BA=; b=MD8NIFAOqNMCEapUgWLJtRvUU1lEGA/PqCBhdpgYJ060w+2yEtawcXa2ej1tAQm+tMNyJg mZ17GdrtrqENIKINb9U+serphNAxlFynw5SH9OG88ixUyEr9Z3z9D/e4lEAIQ/kEp+l8qH cCmTuSIil6OWMD9VhA6tjsYs+6lRgE0= 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-25-89zTgJG3MZONUzFu75kqAQ-1; Tue, 12 May 2020 12:01:53 -0400 X-MC-Unique: 89zTgJG3MZONUzFu75kqAQ-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 9A8F0107B7C3; Tue, 12 May 2020 16:01:51 +0000 (UTC) Received: from gondolin (ovpn-112-176.ams2.redhat.com [10.36.112.176]) by smtp.corp.redhat.com (Postfix) with ESMTP id 5FEFA63F8F; Tue, 12 May 2020 16:01:43 +0000 (UTC) Date: Tue, 12 May 2020 18:01:40 +0200 From: Cornelia Huck To: David Hildenbrand Subject: Re: [PATCH v1 2/8] s390/sclp: check sccb len before filling in data Message-ID: <20200512180140.4be69d60.cohuck@redhat.com> In-Reply-To: <9a39a948-91a1-7cfe-f2a5-d30e5564f318@redhat.com> References: <20200508230823.22956-1-walling@linux.ibm.com> <20200508230823.22956-3-walling@linux.ibm.com> <58bc496c-28bb-26f8-ab46-aba6ad141717@linux.ibm.com> <737869a8-13b2-1831-00c6-629d5a109d9c@redhat.com> <05ab2e59-10c0-c7df-c014-b54883ddccd3@linux.ibm.com> <9a39a948-91a1-7cfe-f2a5-d30e5564f318@redhat.com> Organization: Red Hat GmbH MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=207.211.31.81; envelope-from=cohuck@redhat.com; helo=us-smtp-delivery-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/05/12 01:41:59 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 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, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, SPF_PASS=-0.001 autolearn=_AUTOLEARN 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: Collin Walling , Janosch Frank , mst@redhat.com, qemu-devel@nongnu.org, pasic@linux.ibm.com, borntraeger@de.ibm.com, qemu-s390x@nongnu.org, svens@linux.ibm.com, pbonzini@redhat.com, mihajlov@linux.ibm.com, rth@twiddle.net Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Mon, 11 May 2020 17:02:06 +0200 David Hildenbrand wrote: > On 11.05.20 16:50, Janosch Frank wrote: > > On 5/11/20 4:44 PM, David Hildenbrand wrote: > >> On 11.05.20 16:36, Janosch Frank wrote: > >>> On 5/9/20 1:08 AM, Collin Walling wrote: > >>>> The SCCB must be checked for a sufficient length before it is filled > >>>> with any data. If the length is insufficient, then the SCLP command > >>>> is suppressed and the proper response code is set in the SCCB header. > >>>> > >>>> Signed-off-by: Collin Walling > >>> > >>> Fixes tag? Probably Fixes: 832be0d8a3bb ("s390x: sclp: Report insufficient SCCB length") ? > >>> Reviewed-by: Janosch Frank > >> > >> This is not a fix AFAIKs. > >> sclp_service_call()/sclp_service_call_protected() always supplies a full > >> SCCB of exactly 4k size. > >> > > > > We don't check for QEMU's 4k buffer here, but for the length that was > > specified by the guest. > > > > It's valid for the guest to request cpu info and state that its buffer > > is only 1k. We can't write everything in 1k if we have ~200 cpus, so > > we'll report the insufficient length rc. > > > > What he fixes here is the time of the length check, it should be done > > before any changes are being done to the work_sccb. > > I don't have access to the spec, especially, if the guest can expect > nothing else in the sccb to change in case we report an error code. So > whatever you tell me, I have to trust you :) Same here. Sounds plausible, but I have to trust the folks with the documentation :)