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=-13.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 F0A5AC43460 for ; Wed, 7 Apr 2021 21:24:42 +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 7A4B76103E for ; Wed, 7 Apr 2021 21:24:42 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7A4B76103E 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]:45382 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lUFfF-0007Lv-Li for qemu-devel@archiver.kernel.org; Wed, 07 Apr 2021 17:24:41 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:45580) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lUFeC-0006OQ-W6 for qemu-devel@nongnu.org; Wed, 07 Apr 2021 17:23:37 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:27537) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lUFe9-0007p7-Pz for qemu-devel@nongnu.org; Wed, 07 Apr 2021 17:23:35 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1617830612; 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=Fh7IuNt/LN6GglsAP3oisMRpXDlFvlMwkfrE9MtCzq0=; b=FZuMEcdyxLe8ycofYBRoW5Npf6I7+KDDBY16+eOMEo3own0sFjCGIhhUHm/K3jox2seOMq mmZKIktjACR5UjnZ5fBq9G6Hc+12CjuegdQQXdv1I9i9mtMQn0oPAg4IgisVBfD7xT+8bq gwEn1BKbXV7F9tIFKpiT6x2m0Ij1Wog= 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-64-OOCVp2SYPbeXE8fsae6shw-1; Wed, 07 Apr 2021 17:23:30 -0400 X-MC-Unique: OOCVp2SYPbeXE8fsae6shw-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 75F2519611A1; Wed, 7 Apr 2021 21:23:29 +0000 (UTC) Received: from localhost (unknown [10.40.208.10]) by smtp.corp.redhat.com (Postfix) with ESMTP id 5282F19C78; Wed, 7 Apr 2021 21:23:20 +0000 (UTC) Date: Wed, 7 Apr 2021 23:23:18 +0200 From: Igor Mammedov To: "Michael S. Tsirkin" Subject: Re: [PULL v2 11/19] pci: acpi: ensure that acpi-index is unique Message-ID: <20210407232318.60d8aaf7@redhat.com> In-Reply-To: <20210407092759-mutt-send-email-mst@kernel.org> References: <20210322225907.541943-1-mst@redhat.com> <20210322225907.541943-12-mst@redhat.com> <20210406201546.2377830e@redhat.com> <20210407092759-mutt-send-email-mst@kernel.org> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=imammedo@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Received-SPF: pass client-ip=170.10.133.124; envelope-from=imammedo@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 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_LOW=-0.7, 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 , "Daniel P. =?UTF-8?B?QmVycmFuZ8Op?=" , qemu-devel@nongnu.org, Julia Suvorova Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Wed, 7 Apr 2021 09:29:22 -0400 "Michael S. Tsirkin" wrote: > On Tue, Apr 06, 2021 at 08:15:46PM +0200, Igor Mammedov wrote: > > On Tue, 6 Apr 2021 16:07:25 +0100 > > Daniel P. Berrang=C3=A9 wrote: > > =20 > > > On Tue, Apr 06, 2021 at 03:54:24PM +0100, Daniel P. Berrang=C3=A9 wro= te: =20 > > > > On Mon, Mar 22, 2021 at 07:00:18PM -0400, Michael S. Tsirkin wrote:= =20 > > > > > From: Igor Mammedov > > > > >=20 > > > > > it helps to avoid device naming conflicts when guest OS is > > > > > configured to use acpi-index for naming. > > > > > Spec ialso says so: > > > > >=20 > > > > > PCI Firmware Specification Revision 3.2 > > > > > 4.6.7. _DSM for Naming a PCI or PCI Express Device Under Operati= ng Systems > > > > > " > > > > > Instance number must be unique under \_SB scope. This instance nu= mber does not have to > > > > > be sequential in a given system configuration. > > > > > " > > > > >=20 > > > > > Signed-off-by: Igor Mammedov > > > > > Message-Id: <20210315180102.3008391-4-imammedo@redhat.com> > > > > > Reviewed-by: Michael S. Tsirkin > > > > > Signed-off-by: Michael S. Tsirkin > > > > > --- > > > > > hw/acpi/pcihp.c | 46 +++++++++++++++++++++++++++++++++++++++++++= +++ > > > > > 1 file changed, 46 insertions(+) > > > > >=20 > > > > > diff --git a/hw/acpi/pcihp.c b/hw/acpi/pcihp.c > > > > > index ceab287bd3..f4cb3c979d 100644 > > > > > --- a/hw/acpi/pcihp.c > > > > > +++ b/hw/acpi/pcihp.c > > > > > @@ -52,6 +52,21 @@ typedef struct AcpiPciHpFind { > > > > > PCIBus *bus; > > > > > } AcpiPciHpFind; > > > > > =20 > > > > > +static gint g_cmp_uint32(gconstpointer a, gconstpointer b, gpoin= ter user_data) > > > > > +{ > > > > > + return a - b; > > > > > +} > > > > > + > > > > > +static GSequence *pci_acpi_index_list(void) > > > > > +{ > > > > > + static GSequence *used_acpi_index_list; > > > > > + > > > > > + if (!used_acpi_index_list) { > > > > > + used_acpi_index_list =3D g_sequence_new(NULL); > > > > > + } > > > > > + return used_acpi_index_list; > > > > > +} > > > > > + > > > > > static int acpi_pcihp_get_bsel(PCIBus *bus) > > > > > { > > > > > Error *local_err =3D NULL; > > > > > @@ -277,6 +292,23 @@ void acpi_pcihp_device_pre_plug_cb(HotplugHa= ndler *hotplug_dev, > > > > > ONBOARD_INDEX_MAX); > > > > > return; > > > > > } > > > > > + > > > > > + /* > > > > > + * make sure that acpi-index is unique across all present PC= I devices > > > > > + */ > > > > > + if (pdev->acpi_index) { > > > > > + GSequence *used_indexes =3D pci_acpi_index_list(); > > > > > + > > > > > + if (g_sequence_lookup(used_indexes, GINT_TO_POINTER(pdev= ->acpi_index), > > > > > + g_cmp_uint32, NULL)) { > > > > > + error_setg(errp, "a PCI device with acpi-index =3D %= " PRIu32 > > > > > + " already exist", pdev->acpi_index); > > > > > + return; > > > > > + } > > > > > + g_sequence_insert_sorted(used_indexes, > > > > > + GINT_TO_POINTER(pdev->acpi_inde= x), > > > > > + g_cmp_uint32, NULL); > > > > > + } =20 > > > >=20 > > > > This doesn't appear to ensure uniqueness when using PCIe topologies= : > > > >=20 > > > > $ ./build/x86_64-softmmu/qemu-system-x86_64 \ > > > > -device virtio-net,acpi-index=3D100 \ > > > > -device virtio-net,acpi-index=3D100 > > > > qemu-system-x86_64: -device virtio-net,acpi-index=3D100: a PCI devi= ce with acpi-index =3D 100 already exist > > > >=20 > > > > $ ./build/x86_64-softmmu/qemu-system-x86_64 \ > > > > -M q35 \ > > > > -device virtio-net,acpi-index=3D100 > > > > -device virtio-net,acpi-index=3D100 > > > > ....happily running.... =20 > > >=20 > > > In fact the entire concept doesn't appear to work with Q35 at all as > > > implemented. > > >=20 > > > The 'acpi_index' file in the guest OS never gets created and the NICs > > > are still called 'eth0', 'eth1' > > >=20 > > > Only with i440fx can I can the "enoNNN" based naming to work with > > > acpi-index set from QEMU =20 > >=20 > > It is not supported on Q35 yet as it depends on ACPI PCI hotplug infras= tructure. > > Once Julia is done with porting it to Q35, acpi-index will be pulled al= ong with it. =20 >=20 >=20 > Right. But for now, should we make it fail instead of being ignored silen= tly? > If we don't how will managament find out it's not really supported? > And if we make it fail how will management then find out when it's finall= y > supported? I had an idea to add capability flag to MachineInfo in QMP schema and then do ugly check from PCIDevice.realize() 1) if (acpi_index!=3D0 && current_machine->has_pci_acpi_index) error out However Daniel said that he didn't think that MachineInfo was the right place for it. Problem is that we can't check acpi-index unsupported configuration at PCIDevice.realize() time since we don't know about availability of the feature before first reset event that overrides native PCI hot-plug (SHPC or PCI-E) with ACPI one if it's enabled. Which is too late, since all devices are already created. Neither seems right to do check at PCIDevice.reset() time, as *) it would depend if device hosting ACPI hotplug were reset first *) make every PCI device query for ACPI hotplug controller which is the same current_machine->has_pci_acpi_index only uglier Hence acpi-index is just ignored on machines that do not support it. I don't see any good option to do this check without refactoring ACPI hotplug the way where it's enabled at device creation time. (I think Julia had similar issues with creation/reset ordering in her last Q35 ACPI PCI hotplug series) Any suggestions are welcome. As a quick ugly temporary solution it could be MachineInfo QAPI schema flag or (PC)Machine property with [1] check. After all, It's a board feature and should originate from there (instead of 'random' acpi hw we decided abuse as hotplug controller), and later we can re-factor it internally to propagate flag along PCI hierarchy properly (but external probing will stay the same). PS: I also didn't consider rising a error in mixed configurations, where only some of bridges support ACPI hotplug while some use native one. So that's something to work on. > > > Regards, > > > Daniel =20 >=20