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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 3C31CC6FD19 for ; Thu, 16 Mar 2023 18:43:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Content-Type: Content-Transfer-Encoding:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:From:References:Cc:To:Subject: MIME-Version:Date:Message-ID:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=6ALZ/Az3foUXIvNqveY6PH3PNuj5kBnKKaJyKQvNRDY=; b=GzB+umGNowl4L/ rgDRjCz11rKuzmy5WSWruJR8G/6/LUNO5vJ2oTkanFdK3ts0eE7F6um2cQ+kHzLfOs4aVQlRUa6rA 1AEwGZWOyGCj9VLqba8qoY0OZ8xLwlF/NQmwnqm24cGYD7k6frVKaLho/3vIXudY6PJ/0p0yUbFKK uZO12bMEjefl6I8r6+yIHf2F8Qx4Vkvt9E+v594fTEfNxF4S6tjtNA1XhNJ7UbR+sPUQ0Q532kLmc GENnPJsIN0UfYZeQ8bdKKP1nG5vaFuMz1uE9nJ0awylPNyU1Nw7MAHeioyyUuc3sDyR1BggNe2nAu 2bUu0fUuQnWXhnqL/sXA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1pcsYW-00HHPw-0h; Thu, 16 Mar 2023 18:42:28 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1pcsYP-00HHNn-0p for linux-arm-kernel@lists.infradead.org; Thu, 16 Mar 2023 18:42:26 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 3B8142F4; Thu, 16 Mar 2023 11:42:57 -0700 (PDT) Received: from [10.1.196.40] (e121345-lin.cambridge.arm.com [10.1.196.40]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 09A373F67D; Thu, 16 Mar 2023 11:42:11 -0700 (PDT) Message-ID: Date: Thu, 16 Mar 2023 18:42:07 +0000 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux aarch64; rv:102.0) Gecko/20100101 Thunderbird/102.7.1 Subject: Re: [PATCH v1 01/14] iommu: Add iommu_get_unmanaged_domain helper Content-Language: en-GB To: Nicolin Chen , Jason Gunthorpe Cc: Eric Auger , will@kernel.org, kevin.tian@intel.com, baolu.lu@linux.intel.com, joro@8bytes.org, shameerali.kolothum.thodi@huawei.com, jean-philippe@linaro.org, linux-arm-kernel@lists.infradead.org, iommu@lists.linux.dev, linux-kernel@vger.kernel.org References: <9b1077601cace998533129327f5e7ad946752d29.1678348754.git.nicolinc@nvidia.com> <2118a147-ac95-d846-ad6f-85d7cebca46a@arm.com> <4938b20b-14d8-86f8-e80b-9d8ed9d8f28d@redhat.com> From: Robin Murphy In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230316_114221_403600_C888247F X-CRM114-Status: GOOD ( 21.46 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 16/03/2023 1:21 am, Nicolin Chen wrote: > Hi Robin, > > How do you think about Jason's proposal below? I'd like to see > us come to an agreement on an acceptable solution... I think it's so thoroughly broken that I suspect Cunningham's law might be at play, but fine, you win :) Hopefully it's sufficiently obvious how the other pieces would fit around the patch below. FWIW I'd still prefer a generic domain->s2_domain pointer rather than any op at all, but I'm happy enough with this compromise. Thanks, Robin. ----->8----- Subject: [PATCH] iommu/dma: Support MSIs through nested domains Currently, iommu-dma is the only place outside of IOMMUFD and drivers which might need to be aware of the stage 2 domain encapsulated within a nested domain. This would be in the legacy-VFIO-style case where we're using host-managed MSIs with an identity mapping at stage 1, where it is the underlying stage 2 domain which owns an MSI cookie and holds the corresponding dynamic mappings. Hook up the new op to resolve what we need from a nested domain. Signed-off-by: Robin Murphy --- drivers/iommu/dma-iommu.c | 18 ++++++++++++++++-- 1 file changed, 16 insertions(+), 2 deletions(-) diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c index 99b2646cb5c7..66b0d5fa49f8 100644 --- a/drivers/iommu/dma-iommu.c +++ b/drivers/iommu/dma-iommu.c @@ -1642,6 +1642,20 @@ static struct iommu_dma_msi_page *iommu_dma_get_msi_page(struct device *dev, return NULL; } +/* + * Nested domains may not have an MSI cookie or accept mappings, but they may + * be related to a domain which does, so we let them tell us what they need. + */ +static struct iommu_domain *iommu_dma_get_msi_mapping_domain(struct device *dev) +{ + struct iommu_domain *domain = iommu_get_domain_for_dev(dev); + + if (domain && domain->type == IOMMU_DOMAIN_NESTED && + domain->ops->get_msi_mapping_domain) + domain = domain->ops->get_msi_mapping_domain(domain); + return domain; +} + /** * iommu_dma_prepare_msi() - Map the MSI page in the IOMMU domain * @desc: MSI descriptor, will store the MSI page @@ -1652,7 +1666,7 @@ static struct iommu_dma_msi_page *iommu_dma_get_msi_page(struct device *dev, int iommu_dma_prepare_msi(struct msi_desc *desc, phys_addr_t msi_addr) { struct device *dev = msi_desc_to_dev(desc); - struct iommu_domain *domain = iommu_get_domain_for_dev(dev); + struct iommu_domain *domain = iommu_dma_get_msi_mapping_domain(dev); struct iommu_dma_msi_page *msi_page; static DEFINE_MUTEX(msi_prepare_lock); /* see below */ @@ -1685,7 +1699,7 @@ int iommu_dma_prepare_msi(struct msi_desc *desc, phys_addr_t msi_addr) void iommu_dma_compose_msi_msg(struct msi_desc *desc, struct msi_msg *msg) { struct device *dev = msi_desc_to_dev(desc); - const struct iommu_domain *domain = iommu_get_domain_for_dev(dev); + const struct iommu_domain *domain = iommu_dma_get_msi_mapping_domain(dev); const struct iommu_dma_msi_page *msi_page; msi_page = msi_desc_get_iommu_cookie(desc); -- 2.39.2.101.g768bb238c484.dirty _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel