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. CC: Thomas Gleixner <tglx@xxxxxxxxxxxxx> CC: Jason Cooper <jason@xxxxxxxxxxxxxx> CC: Marc Zyngier <marc.zyngier@xxxxxxx> CC: linux-kernel@xxxxxxxxxxxxxxx Signed-off-by: Robin Murphy <robin.murphy@xxxxxxx> --- drivers/iommu/dma-iommu.c | 141 ++++++++++++++++++++++++++++++++++----- drivers/irqchip/irq-gic-v2m.c | 3 + drivers/irqchip/irq-gic-v3-its.c | 3 + include/linux/dma-iommu.h | 9 +++ 4 files changed, 141 insertions(+), 15 deletions(-) diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c index 00c8a08d56e7..330cce60cad9 100644 --- a/drivers/iommu/dma-iommu.c +++ b/drivers/iommu/dma-iommu.c @@ -25,10 +25,29 @@ #include <linux/huge_mm.h> #include <linux/iommu.h> #include <linux/iova.h> +#include <linux/irq.h> #include <linux/mm.h> #include <linux/scatterlist.h> #include <linux/vmalloc.h> +struct iommu_dma_msi_page { + struct list_head list; + dma_addr_t iova; + u32 phys_lo; + u32 phys_hi; +}; + +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 +62,19 @@ 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 +86,20 @@ 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 +117,7 @@ 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 +184,7 @@ 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 +200,7 @@ 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 +323,7 @@ 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 +415,7 @@ 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 +524,7 @@ 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 +616,85 @@ int iommu_dma_mapping_error(struct device *dev, dma_addr_t dma_addr) { return dma_addr == DMA_ERROR_CODE; } + +static int __iommu_dma_map_msi_page(struct device *dev, struct msi_msg *msg, + struct iommu_domain *domain, struct iommu_dma_msi_page **ppage) +{ + struct iommu_dma_cookie *cookie = domain->iova_cookie; + struct iommu_dma_msi_page *msi_page; + struct iova_domain *iovad = &cookie->iovad; + struct iova *iova; + phys_addr_t msi_addr = (u64)msg->address_hi << 32 | msg->address_lo; + int ret, prot = IOMMU_WRITE | IOMMU_NOEXEC | IOMMU_MMIO; + + msi_page = kzalloc(sizeof(*msi_page), GFP_ATOMIC); + if (!msi_page) + return -ENOMEM; + + iova = __alloc_iova(domain, iovad->granule, dma_get_mask(dev)); + if (!iova) { + ret = -ENOSPC; + goto out_free_page; + } + + msi_page->iova = iova_dma_addr(iovad, iova); + ret = iommu_map(domain, msi_page->iova, msi_addr & ~iova_mask(iovad), + iovad->granule, prot); + if (ret) + goto out_free_iova; + + msi_page->phys_hi = msg->address_hi; + msi_page->phys_lo = msg->address_lo; + INIT_LIST_HEAD(&msi_page->list); + list_add(&msi_page->list, &cookie->msi_page_list); + *ppage = msi_page; + return 0; + +out_free_iova: + __free_iova(iovad, iova); +out_free_page: + kfree(msi_page); + return ret; +} + +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 iova_domain *iovad; + struct iommu_dma_cookie *cookie; + struct iommu_dma_msi_page *msi_page; + int ret = 0; + + if (!domain || !domain->iova_cookie) + return; + + cookie = domain->iova_cookie; + iovad = &cookie->iovad; + + spin_lock(&cookie->msi_lock); + list_for_each_entry(msi_page, &cookie->msi_page_list, list) + if (msi_page->phys_hi == msg->address_hi && + msi_page->phys_lo - msg->address_lo < iovad->granule) + goto unlock; + + ret = __iommu_dma_map_msi_page(dev, msg, domain, &msi_page); +unlock: + spin_unlock(&cookie->msi_lock); + + if (!ret) { + msg->address_hi = upper_32_bits(msi_page->iova); + msg->address_lo &= iova_mask(iovad); + msg->address_lo += lower_32_bits(msi_page->iova); + } else { + /* + * 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; + } +} 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 <linux/acpi.h> +#include <linux/dma-iommu.h> #include <linux/irq.h> #include <linux/irqdomain.h> #include <linux/kernel.h> @@ -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 7ceaba81efb4..73f4f10dc204 100644 --- a/drivers/irqchip/irq-gic-v3-its.c +++ b/drivers/irqchip/irq-gic-v3-its.c @@ -18,6 +18,7 @@ #include <linux/bitmap.h> #include <linux/cpu.h> #include <linux/delay.h> +#include <linux/dma-iommu.h> #include <linux/interrupt.h> #include <linux/log2.h> #include <linux/mm.h> @@ -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 <linux/iommu.h> +#include <linux/msi.h> 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 */ -- 2.8.1.dirty -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html