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=-0.8 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 DD7AAC433DF for ; Tue, 23 Jun 2020 15:04:33 +0000 (UTC) Received: from fraxinus.osuosl.org (smtp4.osuosl.org [140.211.166.137]) (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 8296720774 for ; Tue, 23 Jun 2020 15:04:33 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="uyCRgzzn" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8296720774 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=iommu-bounces@lists.linux-foundation.org Received: from localhost (localhost [127.0.0.1]) by fraxinus.osuosl.org (Postfix) with ESMTP id 60B6B87647; Tue, 23 Jun 2020 15:04:33 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from fraxinus.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id dveLRzHWnd4i; Tue, 23 Jun 2020 15:04:32 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by fraxinus.osuosl.org (Postfix) with ESMTP id D4D6387578; Tue, 23 Jun 2020 15:04:32 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id B0401C088E; Tue, 23 Jun 2020 15:04:32 +0000 (UTC) Received: from silver.osuosl.org (smtp3.osuosl.org [140.211.166.136]) by lists.linuxfoundation.org (Postfix) with ESMTP id CD337C016F for ; Tue, 23 Jun 2020 15:04:30 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by silver.osuosl.org (Postfix) with ESMTP id B23A62637A for ; Tue, 23 Jun 2020 15:04:30 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from silver.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id iByShuw0TXZz for ; Tue, 23 Jun 2020 15:04:29 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by silver.osuosl.org (Postfix) with ESMTPS id 51D3D22CB0 for ; Tue, 23 Jun 2020 15:04:29 +0000 (UTC) Received: from localhost (mobile-166-170-222-206.mycingular.net [166.170.222.206]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 94EC420723; Tue, 23 Jun 2020 15:04:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592924669; bh=pYSmEX90OpGgB4bw3JQlLwOPKGPZt8zcCg2Jw+YWJhM=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=uyCRgzznNIaGzwTA5WSAD0mfkUx7PWjjDA0xuNRfK8wdFyqid6COQmfVRcULXo7eB x6r9H+xRROcynvqijhjGKwufYcigaaHtOMvN1NklZTodXP7DkrU83liurSsGCNLFtO sRrkKEDXRbWwc9kz0no38z13LtKl0kt/Ne0JEuNE= Date: Tue, 23 Jun 2020 10:04:27 -0500 From: Bjorn Helgaas To: Zhangfei Gao Subject: Re: [PATCH 0/2] Introduce PCI_FIXUP_IOMMU Message-ID: <20200623150427.GA2403606@bjorn-Precision-5520> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: Cc: linux-pci , Hanjun Guo , jean-philippe , Herbert Xu , ACPI Devel Maling List , Linux ARM , Len Brown , Thanu Rangarajan , Souvik Chakravarty , Arnd Bergmann , Bjorn Helgaas , wanghuiqiang , kenneth-lee-2012@foxmail.com, Greg Kroah-Hartman , "Rafael J. Wysocki" , "linux-kernel@vger.kernel.org" , "open list:IOMMU DRIVERS" , "open list:HARDWARE RANDOM NUMBER GENERATOR CORE" , Sudeep Holla X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Errors-To: iommu-bounces@lists.linux-foundation.org Sender: "iommu" On Fri, Jun 19, 2020 at 10:26:54AM +0800, Zhangfei Gao wrote: > Have studied _DSM method, two issues we met comparing using quirk. > = > 1. Need change definition of either pci_host_bridge or pci_dev, like addi= ng > member can_stall, > while pci system does not know stall now. > = > a, pci devices do not have uuid: uuid need be described in dsdt, while pci > devices are not defined in dsdt. > =A0=A0=A0 so we have to use host bridge. PCI devices *can* be described in the DSDT. IIUC these particular devices are hardwired (not plug-in cards), so platform firmware can know about them and could describe them in the DSDT. > b,=A0 Parsing dsdt is in in pci subsystem. > Like drivers/acpi/pci_root.c: > =A0=A0=A0=A0=A0=A0 obj =3D acpi_evaluate_dsm(ACPI_HANDLE(bus->bridge), &p= ci_acpi_dsm_guid, > 1, > =A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0= =A0=A0=A0=A0=A0=A0=A0 IGNORE_PCI_BOOT_CONFIG_DSM, NULL); > = > After parsing DSM in pci, we need record this info. > Currently, can_stall info is recorded in iommu_fwspec, > which is allocated in iommu_fwspec_init and called by iort_iommu_configure > for uefi. You can look for a _DSM wherever it is convenient for you. It could be in an AMBA shim layer. > 2. Guest kernel also need support sva. > Using quirk, the guest can boot with sva enabled, since quirk is > self-contained by kernel. > If using=A0 _DSM, a specific uefi or dtb has to be provided, > currently we can useQEMU_EFI.fd from apt install qemu-efi I don't quite understand what this means, but as I mentioned before, a quirk for a *limited* number of devices is OK, as long as there is a plan that removes the need for a quirk for future devices. E.g., if the next platform version ships with a DTB or firmware with a _DSM or other mechanism that enables the kernel to discover this information without a kernel change, it's fine to use a quirk to cover the early platform. The principles are: - I don't want to have to update a quirk for every new Device ID that needs this. - I don't really want to have to manage non-PCI information in the struct pci_dev. If this is AMBA- or IOMMU-related, it should be stored in a structure related to AMBA or the IOMMU. _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu