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=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 724CCC433DB for ; Thu, 18 Feb 2021 08:44:02 +0000 (UTC) Received: from hemlock.osuosl.org (smtp2.osuosl.org [140.211.166.133]) (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 7C69A64E68 for ; Thu, 18 Feb 2021 08:44:01 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7C69A64E68 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=iommu-bounces@lists.linux-foundation.org Received: from localhost (localhost [127.0.0.1]) by hemlock.osuosl.org (Postfix) with ESMTP id 3AD64872BE; Thu, 18 Feb 2021 08:44:01 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from hemlock.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id X91OjM4uFRks; Thu, 18 Feb 2021 08:43:57 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by hemlock.osuosl.org (Postfix) with ESMTP id 62FE486E48; Thu, 18 Feb 2021 08:43:57 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 53DECC000E; Thu, 18 Feb 2021 08:43:57 +0000 (UTC) Received: from fraxinus.osuosl.org (smtp4.osuosl.org [140.211.166.137]) by lists.linuxfoundation.org (Postfix) with ESMTP id D672DC000D for ; Thu, 18 Feb 2021 08:43:55 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by fraxinus.osuosl.org (Postfix) with ESMTP id D148E86141 for ; Thu, 18 Feb 2021 08:43:55 +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 WN244oX1LW3Q for ; Thu, 18 Feb 2021 08:43:54 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from szxga06-in.huawei.com (szxga06-in.huawei.com [45.249.212.32]) by fraxinus.osuosl.org (Postfix) with ESMTPS id 0573E86130 for ; Thu, 18 Feb 2021 08:43:53 +0000 (UTC) Received: from DGGEMS402-HUB.china.huawei.com (unknown [172.30.72.60]) by szxga06-in.huawei.com (SkyGuard) with ESMTP id 4Dh7WF1DQPzjMg3; Thu, 18 Feb 2021 16:42:33 +0800 (CST) Received: from [10.174.184.42] (10.174.184.42) by DGGEMS402-HUB.china.huawei.com (10.3.19.202) with Microsoft SMTP Server id 14.3.498.0; Thu, 18 Feb 2021 16:43:44 +0800 Subject: Re: [PATCH v13 02/15] iommu: Introduce bind/unbind_guest_msi To: Auger Eric , , , , , , , , , , References: <20201118112151.25412-1-eric.auger@redhat.com> <20201118112151.25412-3-eric.auger@redhat.com> <6a70d93d-329f-4129-bd90-03f8589c5de4@huawei.com> <1ef4f5ae-9ca6-7c6d-f8a9-31240e5688c2@redhat.com> From: Keqian Zhu Message-ID: Date: Thu, 18 Feb 2021 16:43:43 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.7.1 MIME-Version: 1.0 In-Reply-To: <1ef4f5ae-9ca6-7c6d-f8a9-31240e5688c2@redhat.com> X-Originating-IP: [10.174.184.42] X-CFilter-Loop: Reflected Cc: jean-philippe@linaro.org, vivek.gautam@arm.com, zhangfei.gao@linaro.org 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="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: iommu-bounces@lists.linux-foundation.org Sender: "iommu" Hi Eric, On 2021/2/12 16:55, Auger Eric wrote: > Hi Keqian, > > On 2/1/21 12:52 PM, Keqian Zhu wrote: >> Hi Eric, >> >> On 2020/11/18 19:21, Eric Auger wrote: >>> On ARM, MSI are translated by the SMMU. An IOVA is allocated >>> for each MSI doorbell. If both the host and the guest are exposed >>> with SMMUs, we end up with 2 different IOVAs allocated by each. >>> guest allocates an IOVA (gIOVA) to map onto the guest MSI >>> doorbell (gDB). The Host allocates another IOVA (hIOVA) to map >>> onto the physical doorbell (hDB). >>> >>> So we end up with 2 untied mappings: >>> S1 S2 >>> gIOVA -> gDB >>> hIOVA -> hDB >>> >>> Currently the PCI device is programmed by the host with hIOVA >>> as MSI doorbell. So this does not work. >>> >>> This patch introduces an API to pass gIOVA/gDB to the host so >>> that gIOVA can be reused by the host instead of re-allocating >>> a new IOVA. So the goal is to create the following nested mapping: >> Does the gDB can be reused under non-nested mode? > > Under non nested mode the hIOVA is allocated within the MSI reserved > region exposed by the SMMU driver, [0x8000000, 80fffff]. see > iommu_dma_prepare_msi/iommu_dma_get_msi_page in dma_iommu.c. this hIOVA > is programmed in the physical device so that the physical SMMU > translates it into the physical doorbell (hDB = host physical ITS So, AFAIU, under non-nested mode, at smmu side, we reuse the workflow of non-virtualization scenario. > doorbell). The gDB is not used at pIOMMU programming level. It is only > used when setting up the KVM irq route. > > Hope this answers your question. Thanks for your explanation! > Thanks, Keqian >> >>> >>> S1 S2 >>> gIOVA -> gDB -> hDB >>> >>> and program the PCI device with gIOVA MSI doorbell. >>> >>> In case we have several devices attached to this nested domain >>> (devices belonging to the same group), they cannot be isolated >>> on guest side either. So they should also end up in the same domain >>> on guest side. We will enforce that all the devices attached to >>> the host iommu domain use the same physical doorbell and similarly >>> a single virtual doorbell mapping gets registered (1 single >>> virtual doorbell is used on guest as well). >>> >> [...] >> >>> + * >>> + * The associated IOVA can be reused by the host to create a nested >>> + * stage2 binding mapping translating into the physical doorbell used >>> + * by the devices attached to the domain. >>> + * >>> + * All devices within the domain must share the same physical doorbell. >>> + * A single MSI GIOVA/GPA mapping can be attached to an iommu_domain. >>> + */ >>> + >>> +int iommu_bind_guest_msi(struct iommu_domain *domain, >>> + dma_addr_t giova, phys_addr_t gpa, size_t size) >>> +{ >>> + if (unlikely(!domain->ops->bind_guest_msi)) >>> + return -ENODEV; >>> + >>> + return domain->ops->bind_guest_msi(domain, giova, gpa, size); >>> +} >>> +EXPORT_SYMBOL_GPL(iommu_bind_guest_msi); >>> + >>> +void iommu_unbind_guest_msi(struct iommu_domain *domain, >>> + dma_addr_t iova) >> nit: s/iova/giova > sure >> >>> +{ >>> + if (unlikely(!domain->ops->unbind_guest_msi)) >>> + return; >>> + >>> + domain->ops->unbind_guest_msi(domain, iova); >>> +} >>> +EXPORT_SYMBOL_GPL(iommu_unbind_guest_msi); >>> + >> [...] >> >> Thanks, >> Keqian >> > > Thanks > > Eric > > . > _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu