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>

1 files changed, 3 insertions, 0 deletions

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 = {