From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alex Williamson Subject: Re: [PATCH v13 03/15] iommu/dma: Allow MSI-only cookies Date: Thu, 6 Oct 2016 14:17:17 -0600 Message-ID: <20161006141717.13c9c111@t450s.home> 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 Return-path: In-Reply-To: <1475743531-4780-4-git-send-email-eric.auger-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Eric Auger Cc: yehuday-eYqpPyKDWXRBDgjK7y7TUQ@public.gmane.org, drjones-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, jason-NLaQJdtUoK4Be96aLqz0jA@public.gmane.org, kvm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, marc.zyngier-5wv7dgnIgG8@public.gmane.org, p.fedin-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org, will.deacon-5wv7dgnIgG8@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, pranav.sawargaonkar-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org, Manish.Jaggi-M3mlKVOIwJVv6pq1l3V1OdBPR1lH4CV8@public.gmane.org, christoffer.dall-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org, eric.auger.pro-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org List-Id: iommu@lists.linux-foundation.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 */