From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755894AbcJFUR2 (ORCPT ); Thu, 6 Oct 2016 16:17:28 -0400 Received: from mx1.redhat.com ([209.132.183.28]:57028 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751448AbcJFURT (ORCPT ); Thu, 6 Oct 2016 16:17:19 -0400 Date: Thu, 6 Oct 2016 14:17:17 -0600 From: Alex Williamson To: Eric Auger Cc: eric.auger.pro@gmail.com, christoffer.dall@linaro.org, marc.zyngier@arm.com, robin.murphy@arm.com, will.deacon@arm.com, joro@8bytes.org, tglx@linutronix.de, jason@lakedaemon.net, linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org, drjones@redhat.com, linux-kernel@vger.kernel.org, Bharat.Bhushan@freescale.com, pranav.sawargaonkar@gmail.com, p.fedin@samsung.com, iommu@lists.linux-foundation.org, Jean-Philippe.Brucker@arm.com, yehuday@marvell.com, Manish.Jaggi@caviumnetworks.com Subject: Re: [PATCH v13 03/15] iommu/dma: Allow MSI-only cookies Message-ID: <20161006141717.13c9c111@t450s.home> In-Reply-To: <1475743531-4780-4-git-send-email-eric.auger@redhat.com> References: <1475743531-4780-1-git-send-email-eric.auger@redhat.com> <1475743531-4780-4-git-send-email-eric.auger@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.32]); Thu, 06 Oct 2016 20:17:19 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 6 Oct 2016 08:45:19 +0000 Eric Auger wrote: > 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 > > --- > > v1 -> v2: > - 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 | 40 ++++++++++++++++++++++++++++++++++++++++ > include/linux/dma-iommu.h | 9 +++++++++ > 2 files changed, 49 insertions(+) > > diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c > index c5ab866..11da1a0 100644 > --- a/drivers/iommu/dma-iommu.c > +++ b/drivers/iommu/dma-iommu.c > @@ -716,3 +716,43 @@ 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 Should this perhaps be iommu_setup_dma_msi_region_cookie, or something along those lines. I'm not sure what we're get'ing. Thanks, Alex > + * @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; > + } > + > + domain->msi_geometry.aperture_start = base; > + domain->msi_geometry.aperture_end = base + size - 1; > + > + cookie = domain->iova_cookie; > + iovad = &cookie->iovad; > + > + 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..1c55413 100644 > --- a/include/linux/dma-iommu.h > +++ b/include/linux/dma-iommu.h > @@ -67,6 +67,9 @@ int iommu_dma_mapping_error(struct device *dev, dma_addr_t dma_addr); > /* 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 */