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=-15.1 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,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 64688C2D0E4 for ; Tue, 17 Nov 2020 18:29:48 +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 74E782462E for ; Tue, 17 Nov 2020 18:29:45 +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="Xv3jjsUf" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 74E782462E 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]:56460 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kf5jc-0006zh-Au for qemu-devel@archiver.kernel.org; Tue, 17 Nov 2020 13:29:44 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:50780) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kf5j1-0006XT-Po for qemu-devel@nongnu.org; Tue, 17 Nov 2020 13:29:07 -0500 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:22319) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1kf5ix-0000Xg-Lt for qemu-devel@nongnu.org; Tue, 17 Nov 2020 13:29:07 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1605637741; 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=PcXANBFnxBTBNedYnZGGYQ1WmhlfzixijmEKnWLfNy0=; b=Xv3jjsUfFsJgWt5ivM4xjaMuWbJvTsLFqlcYVQgfNW3V5QAZL/R4puQf7ycbre+/9K8qVt N7OmJajujgBt8Dla9EPusPB637+QsWHbVHorNQ1XwfANEZ47maUFmSYSfEURARIirZF/8B lG7qJ+gl/yikUGd5Z5Ndr1sY5YQn2W8= 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-568-m1vd8RnMNqOs-btFp-ud1g-1; Tue, 17 Nov 2020 13:28:59 -0500 X-MC-Unique: m1vd8RnMNqOs-btFp-ud1g-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 4B53C80046B; Tue, 17 Nov 2020 18:28:58 +0000 (UTC) Received: from thuth.remote.csb (ovpn-113-138.ams2.redhat.com [10.36.113.138]) by smtp.corp.redhat.com (Postfix) with ESMTP id DF1A95B4A2; Tue, 17 Nov 2020 18:28:49 +0000 (UTC) Subject: Re: [RFC PATCH-for-5.2] hw/s390x/pci: Fix endianness issue To: Matthew Rosato , Cornelia Huck References: <20201117120115.1234994-1-philmd@redhat.com> <20201117143117.4b05db78.cohuck@redhat.com> <20201117151340.539d55b2.cohuck@redhat.com> From: Thomas Huth Message-ID: <7b9967e9-6cfb-d3fa-c62a-ec96f0d97dec@redhat.com> Date: Tue, 17 Nov 2020 19:28:48 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.12.0 MIME-Version: 1.0 In-Reply-To: X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=thuth@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=63.128.21.124; envelope-from=thuth@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/11/17 00:41:22 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, NICE_REPLY_A=-0.001, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham 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: Peter Maydell , Pierre Morel , David Hildenbrand , qemu-s390x , Richard Henderson , QEMU Developers , Halil Pasic , Christian Borntraeger , Alex Williamson , =?UTF-8?Q?Philippe_Mathieu-Daud=c3=a9?= Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 17/11/2020 15.34, Matthew Rosato wrote: > On 11/17/20 9:13 AM, Cornelia Huck wrote: >> On Tue, 17 Nov 2020 09:02:37 -0500 >> Matthew Rosato wrote: >> >>> On 11/17/20 8:31 AM, Cornelia Huck wrote: >>>> On Tue, 17 Nov 2020 14:23:57 +0100 >>>> Pierre Morel wrote: >>>>    >>>>> On 11/17/20 2:00 PM, Peter Maydell wrote: >>>>>> On Tue, 17 Nov 2020 at 12:03, Philippe Mathieu-Daudé >>>>>> wrote: >>>>>>> >>>>>>> Fix an endianness issue reported by Cornelia: >>>>>>>      >>>>>>>> s390x tcg guest on x86, virtio-pci devices are not detected. The >>>>>>>> relevant feature bits are visible to the guest. Same breakage with >>>>>>>> different guest kernels. >>>>>>>> KVM guests and s390x tcg guests on s390x are fine. >>>>>>> >>>>>>> Fixes: 28dc86a0729 ("s390x/pci: use a PCI Group structure") >>>>>>> Reported-by: Cornelia Huck >>>>>>> Signed-off-by: Philippe Mathieu-Daudé >>>>>>> --- >>>>>>> RFC because review-only patch, untested >>>>>>> --- >>>>>>>     hw/s390x/s390-pci-inst.c | 2 +- >>>>>>>     1 file changed, 1 insertion(+), 1 deletion(-) >>>>>>> >>>>>>> diff --git a/hw/s390x/s390-pci-inst.c b/hw/s390x/s390-pci-inst.c >>>>>>> index 58cd041d17f..cfb54b4d8ec 100644 >>>>>>> --- a/hw/s390x/s390-pci-inst.c >>>>>>> +++ b/hw/s390x/s390-pci-inst.c >>>>>>> @@ -305,7 +305,7 @@ int clp_service_call(S390CPU *cpu, uint8_t r2, >>>>>>> uintptr_t ra) >>>>>>>             ClpReqQueryPciGrp *reqgrp = (ClpReqQueryPciGrp *)reqh; >>>>>>>             S390PCIGroup *group; >>>>>>> >>>>>>> -        group = s390_group_find(reqgrp->g); >>>>>>> +        group = s390_group_find(ldl_p(&reqgrp->g)); >>>>>> >>>>>> 'g' in the ClpReqQueryPciGrp struct is a uint32_t, so >>>>>> adding the ldl_p() will have no effect unless (a) the >>>>>> structure is not 4-aligned and (b) the host will fault on >>>>>> unaligned accesses, which isn't the case for x86 hosts. >>>>>> >>>>>> Q: is this struct really in host order, or should we >>>>>> be using ldl_le_p() or ldl_be_p() and friends here and >>>>>> elsewhere? >>>>>> >>>>>> thanks >>>>>> -- PMM >>>>>>       >>>>> >>>>> Hi, I think we better modify the structure here, g should be a byte. >>>>> >>>>> Connie, can you please try this if it resolves the issue? >>>>> >>>>> diff --git a/hw/s390x/s390-pci-inst.h b/hw/s390x/s390-pci-inst.h >>>>> index fa3bf8b5aa..641d19c815 100644 >>>>> --- a/hw/s390x/s390-pci-inst.h >>>>> +++ b/hw/s390x/s390-pci-inst.h >>>>> @@ -146,7 +146,8 @@ typedef struct ClpReqQueryPciGrp { >>>>>         uint32_t fmt; >>>>>         uint64_t reserved1; >>>>>     #define CLP_REQ_QPCIG_MASK_PFGID 0xff >>>>> -    uint32_t g; >>>>> +    uint32_t g0 :24; >>>>> +    uint32_t g  :8; >>>>>         uint32_t reserved2; >>>>>         uint64_t reserved3; >>>>>     } QEMU_PACKED ClpReqQueryPciGrp; >>>>>   >>>> >>>> No, same crash... I fear there are more things broken wrt endianness. >>>>    >>> >>> Sorry, just getting online now, looking at the code....  Are the 2 >>> memcpy calls added in 9670ee75 and 28dc86a0 the issue?  Won't they just >>> present the Q PCI FN / Q PCI FN GRP results in host endianness? >>> >> >> I just re-added some st?_p operations in set_pbdev_info and that fixes >> at least the crash I was seeing with Phil's patch applied. Still, no >> pci functions get detected, so that's not enough. Those memcpy calls >> look like a possible culprit. >> > > OK, so if everything in set_pbdev_info and s390_pci_init_default_group() is > handled with st?_p operations, then the memcpy should be OK... > > Pierre was on to something with his recommendation, as the group id is only > 1B of the 'g' field (see CLP_REQ_QPCIG_MASK_PFGID) - the other bits just > happen to be unused. > > Did you include his change with your st?_p changes to set_pbdev_info As Peter also already wrote: Bitfields are not endianess safe either. You'd need to replace the g0:24 with "uint8_t g0[3]" to get it working that way. Thomas