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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id EE8FCC43334 for ; Mon, 20 Jun 2022 19:08:04 +0000 (UTC) Received: from localhost ([::1]:36106 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1o3Mkl-00069A-Tq for qemu-devel@archiver.kernel.org; Mon, 20 Jun 2022 15:08:03 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:57102) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1o3Mi3-0003mx-PN; Mon, 20 Jun 2022 15:05:16 -0400 Received: from mail-oo1-xc2b.google.com ([2607:f8b0:4864:20::c2b]:44900) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1o3Mi2-0004Uz-45; Mon, 20 Jun 2022 15:05:15 -0400 Received: by mail-oo1-xc2b.google.com with SMTP id v33-20020a4a9764000000b0035f814bb06eso2276852ooi.11; Mon, 20 Jun 2022 12:05:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=message-id:date:mime-version:user-agent:subject:content-language:to :cc:references:from:in-reply-to:content-transfer-encoding; bh=JxRokALGr/J/qfYuKuDDsl3MwKXZIfg3jKdVS4ud76E=; b=Nly7PLpTzP+crJ2r1tkvZMXZEau3w43XZ3bJeyxVL+147fXKHsSaw19DixsrO5OvNc xUxfNQrLNLvBD90ZtxJvryWos04s3t9hVPIT4uPUmGDc1YUJbSc3t8Pswgw0M9cAGZrX cZuiVQ5AETdl/59G/qA2RwWH1MlYjr1/2loaL9JQIR3eD0LgHNQ6A9lncGQrs1yKeQ+6 bpT5CbjvHOFxbxgo1bXZJKVXp18Y0TQezZPJN6khz/kfPlSK1Y8BewpBUrZWPxnWN7EM 3XN5fKD9D4VCUPKZi9Wj6Hhwq5zF34G8ty3n6tvKAeOQ6nkq8UVUwUB+fiuBcEn3knbo N+GA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:message-id:date:mime-version:user-agent:subject :content-language:to:cc:references:from:in-reply-to :content-transfer-encoding; bh=JxRokALGr/J/qfYuKuDDsl3MwKXZIfg3jKdVS4ud76E=; b=bu44YqUK5tmTg/YmwYIvaM8hAiOX4BzKx/5YZcbkMXtgxOSzDZDhDIOjwTkWKLSY6j M9aIGA8CJasCL5YhlZQThD2joxSs8fr1vXlm7He5K25b37KNe8pJcuHcZtJ0Hz8v9RGG e0ivLyyaKXyMXvXVz7WpkdJLlN6Gh/kjEpK8VHpAjZhz1HvRF+ogP5eU/o0qaOR9wcux umDkbtyFfrhA6NDHi7RjB/FFWRQFstcCrq0zeb7RYISgoAeGFsN3JcffC1DXcKE1fYLd dCc+039bJihTxXztetGtX0rRLK+1SGoqcgD2N1eZL4fGHVc99STKkFCY5oEfcwaxAIco +9SQ== X-Gm-Message-State: AJIora/L5e7SGiyXQ+TsUiL0o4mmPeOICj1z7C/blnVBACjy8EzUyfdS DwedBCMl8r6NKe0wf7/ZcahDqWR/hKlF9Q== X-Google-Smtp-Source: AGRyM1u8RL0+bfSKw7NfA4kbzsQHp6wcK8eb/g0RU8UFEZMuKyyDc4dsgSTpNajFQ/iXM/heYph8kA== X-Received: by 2002:a4a:254e:0:b0:35e:679f:5f78 with SMTP id v14-20020a4a254e000000b0035e679f5f78mr9575554ooe.26.1655751912001; Mon, 20 Jun 2022 12:05:12 -0700 (PDT) Received: from [192.168.10.102] ([187.34.29.129]) by smtp.gmail.com with ESMTPSA id u2-20020acaab02000000b0032eafcbd294sm7798266oie.16.2022.06.20.12.05.10 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 20 Jun 2022 12:05:11 -0700 (PDT) Message-ID: <675e09f8-ab0c-d2c7-e0f0-1f3c57bb7dd6@gmail.com> Date: Mon, 20 Jun 2022 16:05:03 -0300 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.10.0 Subject: Re: [PATCH v2 3/9] ppc/pnv: use dev->parent_bus->parent to get the PHB Content-Language: en-US To: Mark Cave-Ayland , qemu-devel@nongnu.org Cc: qemu-ppc@nongnu.org, clg@kaod.org, fbarrat@linux.ibm.com References: <20220618110202.87735-1-danielhb413@gmail.com> <20220618110202.87735-4-danielhb413@gmail.com> From: Daniel Henrique Barboza In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=2607:f8b0:4864:20::c2b; envelope-from=danielhb413@gmail.com; helo=mail-oo1-xc2b.google.com X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, FREEMAIL_ENVFROM_END_DIGIT=0.25, FREEMAIL_FROM=0.001, NICE_REPLY_A=-0.001, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 6/20/22 04:27, Mark Cave-Ayland wrote: > On 18/06/2022 12:01, Daniel Henrique Barboza wrote: > >> It is not advisable to execute an object_dynamic_cast() to poke into >> bus->qbus.parent and follow it up with a C cast into the PnvPHB type we >> think we got. >> >> A better way is to access the PnvPHB object via a QOM macro accessing >> the existing parent links of the DeviceState. For a given >> pnv-phb3/4-root-port 'dev', dev->parent_bus will give us the PHB bus, >> and dev->parent_bus->parent is the PHB. Use the adequate QOM macro to >> assert the type, and keep the NULL check in case we didn't get the >> object we were expecting. >> >> Signed-off-by: Daniel Henrique Barboza >> --- >>   hw/pci-host/pnv_phb3.c | 10 +++++++--- >>   hw/pci-host/pnv_phb4.c | 10 +++++++--- >>   2 files changed, 14 insertions(+), 6 deletions(-) >> >> diff --git a/hw/pci-host/pnv_phb3.c b/hw/pci-host/pnv_phb3.c >> index 4ba660f8b9..5e7f827415 100644 >> --- a/hw/pci-host/pnv_phb3.c >> +++ b/hw/pci-host/pnv_phb3.c >> @@ -1139,12 +1139,16 @@ static void pnv_phb3_root_port_realize(DeviceState *dev, Error **errp) >>   { >>       PCIERootPortClass *rpc = PCIE_ROOT_PORT_GET_CLASS(dev); >>       PCIDevice *pci = PCI_DEVICE(dev); >> -    PCIBus *bus = pci_get_bus(pci); >>       PnvPHB3 *phb = NULL; >>       Error *local_err = NULL; >> -    phb = (PnvPHB3 *) object_dynamic_cast(OBJECT(bus->qbus.parent), >> -                                          TYPE_PNV_PHB3); >> +    /* >> +     * dev->parent_bus gives access to the pnv-phb-root bus. >> +     * The PnvPHB3 is the owner (parent) of the bus. >> +     */ >> +    if (dev->parent_bus) { > > Here dev->parent_bus shouldn't be accessed directly: you should use qdev_get_parent_bus() instead. > >> +        phb = PNV_PHB3(dev->parent_bus->parent); >> +    } > > This one is a bit trickier, since part of the qdev design is that devices should only be aware of their immediate bus, and not the device parenting that bus i.e. dev->parent_bus->parent shouldn't be allowed. > > What is really needed here is to use QOM links (or embed the device as a suitable QOM child) to get the PHB reference which I imagine will be changed as part of the follow-up series. So I think this can be left as-is for now, and fixed later. In the previous patch (2) I've put the root port as a child of the bus, giving us this hierarchy: /pnv-phb3[0] (pnv-phb3) <====== PHB /lsi (ics) /msi (phb3-msi) /msi32[0] (memory-region) /msi64[0] (memory-region) /pbcq (pnv-pbcq) (...) /phb3_iommu[0] (pnv-phb3-iommu-memory-region) /pnv-phb3-root.0 (pnv-phb3-root) <=== bus /pnv-phb3-root-port[0] (pnv-phb3-root-port) <==== root-port /bus master container[0] (memory-region) /bus master[0] (memory-region) /pci_bridge_io[0] (memory-region) /pci_bridge_io[1] (memory-region) /pci_bridge_mem[0] (memory-region) /pci_bridge_pci[0] (memory-region) /pci_bridge_pref_mem[0] (memory-region) /pci_bridge_vga_io_hi[0] (memory-region) /pci_bridge_vga_io_lo[0] (memory-region) /pci_bridge_vga_mem[0] (memory-region) /pcie.0 (PCIE) I did it like this instead of the PHB for no particular reason. If the root port of other PHBs are located as a direct child of the PHB I can change it. All that said, thinking more about it, since I need to access the PHB just to set "chassis" and "slot" of the device, and I'm already setting a QOM parent for it, I guess I'll just set that before root_port_realize() and spare us from having to accessing the parent of the parent bus of the root_port. Thanks, Daniel > >>       if (!phb) { >>           error_setg(errp, >> diff --git a/hw/pci-host/pnv_phb4.c b/hw/pci-host/pnv_phb4.c >> index ffd9d8a947..a0ee52e820 100644 >> --- a/hw/pci-host/pnv_phb4.c >> +++ b/hw/pci-host/pnv_phb4.c >> @@ -1782,12 +1782,16 @@ static void pnv_phb4_root_port_realize(DeviceState *dev, Error **errp) >>   { >>       PCIERootPortClass *rpc = PCIE_ROOT_PORT_GET_CLASS(dev); >>       PCIDevice *pci = PCI_DEVICE(dev); >> -    PCIBus *bus = pci_get_bus(pci); >>       PnvPHB4 *phb = NULL; >>       Error *local_err = NULL; >> -    phb = (PnvPHB4 *) object_dynamic_cast(OBJECT(bus->qbus.parent), >> -                                          TYPE_PNV_PHB4); >> +    /* >> +     * dev->parent_bus gives access to the pnv-phb-root bus. >> +     * The PnvPHB4 is the owner (parent) of the bus. >> +     */ >> +    if (dev->parent_bus) { >> +        phb = PNV_PHB4(dev->parent_bus->parent); >> +    } >>       if (!phb) { >>           error_setg(errp, "%s must be connected to pnv-phb4 buses", dev->id); > > I've had a quick look over the rest of the series and from what I can see this is definitely heading in the right direction :) > > > ATB, > > Mark.