[PATCH v2 2/3] gicv3, its: Introduce VFIO map and unmap operations

[Pavel Fedin <p.fedin@xxxxxxxxxxx>]

These new functions use the supplied IOMMU in order to map and unmap MSI
translation register(s).

Signed-off-by: Pavel Fedin <p.fedin@xxxxxxxxxxx>
---
 drivers/irqchip/irq-gic-v3-its.c   | 31 +++++++++++++++++++++++++++++++
 include/linux/irqchip/arm-gic-v3.h |  2 ++
 include/linux/msi.h                | 12 ++++++++++++
 3 files changed, 45 insertions(+)

diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index e23d1d1..b97dfd7 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -29,6 +29,7 @@
 #include <linux/of_platform.h>
 #include <linux/percpu.h>
 #include <linux/slab.h>
+#include <linux/vfio.h>
 
 #include <linux/irqchip.h>
 #include <linux/irqchip/arm-gic-v3.h>
@@ -1257,8 +1258,38 @@ out:
 	return 0;
 }
 
+#if IS_ENABLED(CONFIG_VFIO)
+
+static int its_vfio_map(struct irq_domain *domain,
+			const struct vfio_iommu_driver_ops *ops,
+			void *iommu_data)
+{
+	struct msi_domain_info *msi_info = msi_get_domain_info(domain);
+	struct its_node *its = msi_info->data;
+	u64 addr = its->phys_base + GIC_V3_ITS_CONTROL_SIZE;
+
+	return ops->map(iommu_data, addr, addr, 1, IOMMU_READ|IOMMU_WRITE);
+}
+
+static void its_vfio_unmap(struct irq_domain *domain,
+			   const struct vfio_iommu_driver_ops *ops,
+			   void *iommu_data)
+{
+	struct msi_domain_info *msi_info = msi_get_domain_info(domain);
+	struct its_node *its = msi_info->data;
+	u64 addr = its->phys_base + GIC_V3_ITS_CONTROL_SIZE;
+
+	ops->unmap(iommu_data, addr, 1);
+}
+
+#endif
+
 static struct msi_domain_ops its_msi_domain_ops = {
 	.msi_prepare	= its_msi_prepare,
+#if IS_ENABLED(CONFIG_VFIO)
+	.vfio_map	= its_vfio_map,
+	.vfio_unmap	= its_vfio_unmap,
+#endif
 };
 
 static int its_irq_gic_domain_alloc(struct irq_domain *domain,
diff --git a/include/linux/irqchip/arm-gic-v3.h b/include/linux/irqchip/arm-gic-v3.h
index bff3eee..dfd2bed 100644
--- a/include/linux/irqchip/arm-gic-v3.h
+++ b/include/linux/irqchip/arm-gic-v3.h
@@ -241,6 +241,8 @@
 #define GITS_BASER_TYPE_RESERVED6	6
 #define GITS_BASER_TYPE_RESERVED7	7
 
+#define GIC_V3_ITS_CONTROL_SIZE		0x10000
+
 /*
  * ITS commands
  */
diff --git a/include/linux/msi.h b/include/linux/msi.h
index f71a25e..48faea9 100644
--- a/include/linux/msi.h
+++ b/include/linux/msi.h
@@ -155,6 +155,8 @@ void arch_restore_msi_irqs(struct pci_dev *dev);
 void default_teardown_msi_irqs(struct pci_dev *dev);
 void default_restore_msi_irqs(struct pci_dev *dev);
 
+struct vfio_iommu_driver_ops;
+
 struct msi_controller {
 	struct module *owner;
 	struct device *dev;
@@ -189,6 +191,8 @@ struct msi_domain_info;
  * @msi_finish:		Optional callbacl to finalize the allocation
  * @set_desc:		Set the msi descriptor for an interrupt
  * @handle_error:	Optional error handler if the allocation fails
+ * @vfio_map:		Map the MSI hardware for VFIO
+ * @vfio_unmap:		Unmap the MSI hardware for VFIO
  *
  * @get_hwirq, @msi_init and @msi_free are callbacks used by
  * msi_create_irq_domain() and related interfaces
@@ -218,6 +222,14 @@ struct msi_domain_ops {
 				    struct msi_desc *desc);
 	int		(*handle_error)(struct irq_domain *domain,
 					struct msi_desc *desc, int error);
+#if IS_ENABLED(CONFIG_VFIO)
+	int		(*vfio_map)(struct irq_domain *domain,
+				    const struct vfio_iommu_driver_ops *ops,
+				    void *iommu_data);
+	void		(*vfio_unmap)(struct irq_domain *domain,
+				      const struct vfio_iommu_driver_ops *ops,
+				      void *iommu_data);
+#endif
 };
 
 /**
-- 
2.4.4

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