From 44bb7e243bd4b4e5c79de2452cd9762582f58925 Mon Sep 17 00:00:00 2001 From: Robin Murphy Date: Mon, 12 Sep 2016 17:13:59 +0100 Subject: iommu/dma: Add support for mapping MSIs When an MSI doorbell is located downstream of an IOMMU, attaching devices to a DMA ops domain and switching on translation leads to a rude shock when their attempt to write to the physical address returned by the irqchip driver faults (or worse, writes into some already-mapped buffer) and no interrupt is forthcoming. Address this by adding a hook for relevant irqchip drivers to call from their compose_msi_msg() callback, to swizzle the physical address with an appropriatly-mapped IOVA for any device attached to one of our DMA ops domains. Acked-by: Thomas Gleixner Acked-by: Marc Zyngier Signed-off-by: Robin Murphy Signed-off-by: Will Deacon --- drivers/iommu/dma-iommu.c | 136 ++++++++++++++++++++++++++++++++++----- drivers/irqchip/irq-gic-v2m.c | 3 + drivers/irqchip/irq-gic-v3-its.c | 3 + include/linux/dma-iommu.h | 9 +++ 4 files changed, 136 insertions(+), 15 deletions(-) diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c index 00c8a08d56e7..4329d18080cf 100644 --- a/drivers/iommu/dma-iommu.c +++ b/drivers/iommu/dma-iommu.c @@ -25,10 +25,28 @@ #include #include #include +#include #include #include #include +struct iommu_dma_msi_page { + struct list_head list; + dma_addr_t iova; + phys_addr_t phys; +}; + +struct iommu_dma_cookie { + struct iova_domain iovad; + struct list_head msi_page_list; + spinlock_t msi_lock; +}; + +static inline struct iova_domain *cookie_iovad(struct iommu_domain *domain) +{ + return &((struct iommu_dma_cookie *)domain->iova_cookie)->iovad; +} + int iommu_dma_init(void) { return iova_cache_get(); @@ -43,15 +61,19 @@ int iommu_dma_init(void) */ int iommu_get_dma_cookie(struct iommu_domain *domain) { - struct iova_domain *iovad; + struct iommu_dma_cookie *cookie; if (domain->iova_cookie) return -EEXIST; - iovad = kzalloc(sizeof(*iovad), GFP_KERNEL); - domain->iova_cookie = iovad; + cookie = kzalloc(sizeof(*cookie), GFP_KERNEL); + if (!cookie) + return -ENOMEM; - return iovad ? 0 : -ENOMEM; + spin_lock_init(&cookie->msi_lock); + INIT_LIST_HEAD(&cookie->msi_page_list); + domain->iova_cookie = cookie; + return 0; } EXPORT_SYMBOL(iommu_get_dma_cookie); @@ -63,14 +85,20 @@ EXPORT_SYMBOL(iommu_get_dma_cookie); */ void iommu_put_dma_cookie(struct iommu_domain *domain) { - struct iova_domain *iovad = domain->iova_cookie; + struct iommu_dma_cookie *cookie = domain->iova_cookie; + struct iommu_dma_msi_page *msi, *tmp; - if (!iovad) + if (!cookie) return; - if (iovad->granule) - put_iova_domain(iovad); - kfree(iovad); + if (cookie->iovad.granule) + put_iova_domain(&cookie->iovad); + + list_for_each_entry_safe(msi, tmp, &cookie->msi_page_list, list) { + list_del(&msi->list); + kfree(msi); + } + kfree(cookie); domain->iova_cookie = NULL; } EXPORT_SYMBOL(iommu_put_dma_cookie); @@ -88,7 +116,7 @@ EXPORT_SYMBOL(iommu_put_dma_cookie); */ int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base, u64 size) { - struct iova_domain *iovad = domain->iova_cookie; + struct iova_domain *iovad = cookie_iovad(domain); unsigned long order, base_pfn, end_pfn; if (!iovad) @@ -155,7 +183,7 @@ int dma_direction_to_prot(enum dma_data_direction dir, bool coherent) static struct iova *__alloc_iova(struct iommu_domain *domain, size_t size, dma_addr_t dma_limit) { - struct iova_domain *iovad = domain->iova_cookie; + struct iova_domain *iovad = cookie_iovad(domain); unsigned long shift = iova_shift(iovad); unsigned long length = iova_align(iovad, size) >> shift; @@ -171,7 +199,7 @@ static struct iova *__alloc_iova(struct iommu_domain *domain, size_t size, /* The IOVA allocator knows what we mapped, so just unmap whatever that was */ static void __iommu_dma_unmap(struct iommu_domain *domain, dma_addr_t dma_addr) { - struct iova_domain *iovad = domain->iova_cookie; + struct iova_domain *iovad = cookie_iovad(domain); unsigned long shift = iova_shift(iovad); unsigned long pfn = dma_addr >> shift; struct iova *iova = find_iova(iovad, pfn); @@ -294,7 +322,7 @@ struct page **iommu_dma_alloc(struct device *dev, size_t size, gfp_t gfp, void (*flush_page)(struct device *, const void *, phys_addr_t)) { struct iommu_domain *domain = iommu_get_domain_for_dev(dev); - struct iova_domain *iovad = domain->iova_cookie; + struct iova_domain *iovad = cookie_iovad(domain); struct iova *iova; struct page **pages; struct sg_table sgt; @@ -386,7 +414,7 @@ dma_addr_t iommu_dma_map_page(struct device *dev, struct page *page, { dma_addr_t dma_addr; struct iommu_domain *domain = iommu_get_domain_for_dev(dev); - struct iova_domain *iovad = domain->iova_cookie; + struct iova_domain *iovad = cookie_iovad(domain); phys_addr_t phys = page_to_phys(page) + offset; size_t iova_off = iova_offset(iovad, phys); size_t len = iova_align(iovad, size + iova_off); @@ -495,7 +523,7 @@ int iommu_dma_map_sg(struct device *dev, struct scatterlist *sg, int nents, int prot) { struct iommu_domain *domain = iommu_get_domain_for_dev(dev); - struct iova_domain *iovad = domain->iova_cookie; + struct iova_domain *iovad = cookie_iovad(domain); struct iova *iova; struct scatterlist *s, *prev = NULL; dma_addr_t dma_addr; @@ -587,3 +615,81 @@ int iommu_dma_mapping_error(struct device *dev, dma_addr_t dma_addr) { return dma_addr == DMA_ERROR_CODE; } + +static struct iommu_dma_msi_page *iommu_dma_get_msi_page(struct device *dev, + phys_addr_t msi_addr, struct iommu_domain *domain) +{ + struct iommu_dma_cookie *cookie = domain->iova_cookie; + struct iommu_dma_msi_page *msi_page; + struct iova_domain *iovad = &cookie->iovad; + struct iova *iova; + int prot = IOMMU_WRITE | IOMMU_NOEXEC | IOMMU_MMIO; + + msi_addr &= ~(phys_addr_t)iova_mask(iovad); + list_for_each_entry(msi_page, &cookie->msi_page_list, list) + if (msi_page->phys == msi_addr) + return msi_page; + + msi_page = kzalloc(sizeof(*msi_page), GFP_ATOMIC); + if (!msi_page) + return NULL; + + iova = __alloc_iova(domain, iovad->granule, dma_get_mask(dev)); + if (!iova) + goto out_free_page; + + msi_page->phys = msi_addr; + msi_page->iova = iova_dma_addr(iovad, iova); + if (iommu_map(domain, msi_page->iova, msi_addr, iovad->granule, prot)) + goto out_free_iova; + + INIT_LIST_HEAD(&msi_page->list); + list_add(&msi_page->list, &cookie->msi_page_list); + return msi_page; + +out_free_iova: + __free_iova(iovad, iova); +out_free_page: + kfree(msi_page); + return NULL; +} + +void iommu_dma_map_msi_msg(int irq, struct msi_msg *msg) +{ + struct device *dev = msi_desc_to_dev(irq_get_msi_desc(irq)); + struct iommu_domain *domain = iommu_get_domain_for_dev(dev); + struct iommu_dma_cookie *cookie; + struct iommu_dma_msi_page *msi_page; + phys_addr_t msi_addr = (u64)msg->address_hi << 32 | msg->address_lo; + unsigned long flags; + + if (!domain || !domain->iova_cookie) + return; + + cookie = domain->iova_cookie; + + /* + * We disable IRQs to rule out a possible inversion against + * irq_desc_lock if, say, someone tries to retarget the affinity + * of an MSI from within an IPI handler. + */ + spin_lock_irqsave(&cookie->msi_lock, flags); + msi_page = iommu_dma_get_msi_page(dev, msi_addr, domain); + spin_unlock_irqrestore(&cookie->msi_lock, flags); + + if (WARN_ON(!msi_page)) { + /* + * We're called from a void callback, so the best we can do is + * 'fail' by filling the message with obviously bogus values. + * Since we got this far due to an IOMMU being present, it's + * not like the existing address would have worked anyway... + */ + msg->address_hi = ~0U; + msg->address_lo = ~0U; + msg->data = ~0U; + } else { + msg->address_hi = upper_32_bits(msi_page->iova); + msg->address_lo &= iova_mask(&cookie->iovad); + msg->address_lo += lower_32_bits(msi_page->iova); + } +} diff --git a/drivers/irqchip/irq-gic-v2m.c b/drivers/irqchip/irq-gic-v2m.c index 35eb7ac5d21f..863e073c6f7f 100644 --- a/drivers/irqchip/irq-gic-v2m.c +++ b/drivers/irqchip/irq-gic-v2m.c @@ -16,6 +16,7 @@ #define pr_fmt(fmt) "GICv2m: " fmt #include +#include #include #include #include @@ -108,6 +109,8 @@ static void gicv2m_compose_msi_msg(struct irq_data *data, struct msi_msg *msg) if (v2m->flags & GICV2M_NEEDS_SPI_OFFSET) msg->data -= v2m->spi_offset; + + iommu_dma_map_msi_msg(data->irq, msg); } static struct irq_chip gicv2m_irq_chip = { diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c index 36b9c28a5c91..98ff669d5962 100644 --- a/drivers/irqchip/irq-gic-v3-its.c +++ b/drivers/irqchip/irq-gic-v3-its.c @@ -18,6 +18,7 @@ #include #include #include +#include #include #include #include @@ -655,6 +656,8 @@ static void its_irq_compose_msi_msg(struct irq_data *d, struct msi_msg *msg) msg->address_lo = addr & ((1UL << 32) - 1); msg->address_hi = addr >> 32; msg->data = its_get_event_id(d); + + iommu_dma_map_msi_msg(d->irq, msg); } static struct irq_chip its_irq_chip = { diff --git a/include/linux/dma-iommu.h b/include/linux/dma-iommu.h index 81c5c8d167ad..5ee806e41b5c 100644 --- a/include/linux/dma-iommu.h +++ b/include/linux/dma-iommu.h @@ -21,6 +21,7 @@ #ifdef CONFIG_IOMMU_DMA #include +#include int iommu_dma_init(void); @@ -62,9 +63,13 @@ void iommu_dma_unmap_sg(struct device *dev, struct scatterlist *sg, int nents, int iommu_dma_supported(struct device *dev, u64 mask); 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); + #else struct iommu_domain; +struct msi_msg; static inline int iommu_dma_init(void) { @@ -80,6 +85,10 @@ static inline void iommu_put_dma_cookie(struct iommu_domain *domain) { } +static inline void iommu_dma_map_msi_msg(int irq, struct msi_msg *msg) +{ +} + #endif /* CONFIG_IOMMU_DMA */ #endif /* __KERNEL__ */ #endif /* __DMA_IOMMU_H */ -- cgit v1.2.3