[PATCH v7 21/22] iommu/dma: Add support for mapping MSIs
Nipun Gupta
nipun.gupta at nxp.com
Wed Oct 5 00:00:42 PDT 2016
> -----Original Message-----
> From: iommu-bounces at lists.linux-foundation.org [mailto:iommu-
> bounces at lists.linux-foundation.org] On Behalf Of Robin Murphy
> Sent: Monday, September 12, 2016 21:44
> To: will.deacon at arm.com; joro at 8bytes.org; iommu at lists.linux-
> foundation.org; linux-arm-kernel at lists.infradead.org
> Cc: devicetree at vger.kernel.org; punit.agrawal at arm.com;
> thunder.leizhen at huawei.com
> Subject: [PATCH v7 21/22] 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 <tglx at linutronix.de>
> Acked-by: Marc Zyngier <marc.zyngier at arm.com>
> Signed-off-by: Robin Murphy <robin.murphy at arm.com>
> ---
> 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 <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;
> + 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));
I think this should be 'iova = __alloc_iova(domain, iovad->granule, dma_get_mask(dev));'
as __alloc_iova takes input parameter as 'struct iova_domain *'
Regards,
Nipun
> + 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 <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 36b9c28a5c91..98ff669d5962 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
>
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