Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933112AbcKCVkF (ORCPT ); Thu, 3 Nov 2016 17:40:05 -0400 Received: from mx1.redhat.com ([209.132.183.28]:45720 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760508AbcKCVkD (ORCPT ); Thu, 3 Nov 2016 17:40:03 -0400 From: Eric Auger To: eric.auger@redhat.com, eric.auger.pro@gmail.com, christoffer.dall@linaro.org, marc.zyngier@arm.com, robin.murphy@arm.com, alex.williamson@redhat.com, will.deacon@arm.com, joro@8bytes.org, tglx@linutronix.de, jason@lakedaemon.net, linux-arm-kernel@lists.infradead.org Cc: kvm@vger.kernel.org, drjones@redhat.com, linux-kernel@vger.kernel.org, pranav.sawargaonkar@gmail.com, iommu@lists.linux-foundation.org, punit.agrawal@arm.com, diana.craciun@nxp.com Subject: [RFC 3/8] iommu/dma: Allow MSI-only cookies Date: Thu, 3 Nov 2016 21:39:33 +0000 Message-Id: <1478209178-3009-4-git-send-email-eric.auger@redhat.com> In-Reply-To: <1478209178-3009-1-git-send-email-eric.auger@redhat.com> References: <1478209178-3009-1-git-send-email-eric.auger@redhat.com> X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.31]); Thu, 03 Nov 2016 21:40:02 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3529 Lines: 111 From: Robin Murphy IOMMU domain users such as VFIO face a similar problem to DMA API ops with regard to mapping MSI messages in systems where the MSI write is subject to IOMMU translation. With the relevant infrastructure now in place for managed DMA domains, it's actually really simple for other users to piggyback off that and reap the benefits without giving up their own IOVA management, and without having to reinvent their own wheel in the MSI layer. Allow such users to opt into automatic MSI remapping by dedicating a region of their IOVA space to a managed cookie. Signed-off-by: Robin Murphy Signed-off-by: Eric Auger --- v13 -> v14: - restore reserve_iova for iova >= base + size v1 -> v13 incorpration: - compared to Robin's version - add NULL last param to iommu_dma_init_domain - set the msi_geometry aperture - I removed if (base < U64_MAX - size) reserve_iova(iovad, iova_pfn(iovad, base + size), ULONG_MAX); don't get why we would reserve something out of the scope of the iova domain? what do I miss? --- drivers/iommu/dma-iommu.c | 39 +++++++++++++++++++++++++++++++++++++++ include/linux/dma-iommu.h | 9 +++++++++ 2 files changed, 48 insertions(+) diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c index c5ab866..d45f9a0 100644 --- a/drivers/iommu/dma-iommu.c +++ b/drivers/iommu/dma-iommu.c @@ -716,3 +716,42 @@ void iommu_dma_map_msi_msg(int irq, struct msi_msg *msg) msg->address_lo += lower_32_bits(msi_page->iova); } } + +/** + * iommu_get_dma_msi_region_cookie - Configure a domain for MSI remapping only + * @domain: IOMMU domain to prepare + * @base: Base address of IOVA region to use as the MSI remapping aperture + * @size: Size of the desired MSI aperture + * + * Users who manage their own IOVA allocation and do not want DMA API support, + * but would still like to take advantage of automatic MSI remapping, can use + * this to initialise their own domain appropriately. + */ +int iommu_get_dma_msi_region_cookie(struct iommu_domain *domain, + dma_addr_t base, u64 size) +{ + struct iommu_dma_cookie *cookie; + struct iova_domain *iovad; + int ret; + + if (domain->type == IOMMU_DOMAIN_DMA) + return -EINVAL; + + ret = iommu_get_dma_cookie(domain); + if (ret) + return ret; + + ret = iommu_dma_init_domain(domain, base, size, NULL); + if (ret) { + iommu_put_dma_cookie(domain); + return ret; + } + + cookie = domain->iova_cookie; + iovad = &cookie->iovad; + if (base < U64_MAX - size) + reserve_iova(iovad, iova_pfn(iovad, base + size), ULONG_MAX); + + return 0; +} +EXPORT_SYMBOL(iommu_get_dma_msi_region_cookie); diff --git a/include/linux/dma-iommu.h b/include/linux/dma-iommu.h index 32c5890..05ab5b4 100644 --- a/include/linux/dma-iommu.h +++ b/include/linux/dma-iommu.h @@ -67,6 +67,9 @@ void iommu_dma_unmap_sg(struct device *dev, struct scatterlist *sg, int nents, /* The DMA API isn't _quite_ the whole story, though... */ void iommu_dma_map_msi_msg(int irq, struct msi_msg *msg); +int iommu_get_dma_msi_region_cookie(struct iommu_domain *domain, + dma_addr_t base, u64 size); + #else struct iommu_domain; @@ -90,6 +93,12 @@ static inline void iommu_dma_map_msi_msg(int irq, struct msi_msg *msg) { } +static inline int iommu_get_dma_msi_region_cookie(struct iommu_domain *domain, + dma_addr_t base, u64 size) +{ + return -ENODEV; +} + #endif /* CONFIG_IOMMU_DMA */ #endif /* __KERNEL__ */ #endif /* __DMA_IOMMU_H */ -- 1.9.1