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@linutronix.de>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
diff --git a/include/linux/dma-iommu.h b/include/linux/dma-iommu.h
index 81c5c8d1..5ee806e 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 @@
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_dma_map_msi_msg(int irq, struct msi_msg *msg)
+{
+}
+
#endif /* CONFIG_IOMMU_DMA */
#endif /* __KERNEL__ */
#endif /* __DMA_IOMMU_H */