[Qemu-devel] [RFC PATCH 3/8] iommu: Introduce iommu do invalidate API function

["Liu, Yi L" <yi.l.liu@intel.com>]

From: "Liu, Yi L" <yi.l.liu@linux.intel.com>

When a SVM capable device is assigned to a guest, the first level page
tables are owned by the guest and the guest PASID table pointer is
linked to the device context entry of the physical IOMMU.

Host IOMMU driver has no knowledge of caching structure updates unless
the guest invalidation activities are passed down to the host. The
primary usage is derived from emulated IOMMU in the guest, where QEMU
can trap invalidation activities before pass them down the
host/physical IOMMU. There are IOMMU architectural specific actions
need to be taken which requires the generic APIs introduced in this
patch to have opaque data in the tlb_invalidate_info argument.

Signed-off-by: Liu, Yi L <yi.l.liu@linux.intel.com>
Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
---
 drivers/iommu/iommu.c | 13 +++++++++++++
 include/linux/iommu.h | 16 ++++++++++++++++
 2 files changed, 29 insertions(+)

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index f2da636..ca7cff2 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -1153,6 +1153,19 @@ int iommu_unbind_pasid_table(struct iommu_domain *domain, struct device *dev)
 }
 EXPORT_SYMBOL_GPL(iommu_unbind_pasid_table);
 
+int iommu_do_invalidate(struct iommu_domain *domain,
+		struct device *dev, struct tlb_invalidate_info *inv_info)
+{
+	int ret = 0;
+
+	if (unlikely(domain->ops->do_invalidate == NULL))
+		return -ENODEV;
+
+	ret = domain->ops->do_invalidate(domain, dev, inv_info);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(iommu_do_invalidate);
+
 static void __iommu_detach_device(struct iommu_domain *domain,
 				  struct device *dev)
 {
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 491a011..a48e3b75 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -140,6 +140,11 @@ struct pasid_table_info {
 	__u8	opaque[];/* IOMMU-specific details */
 };
 
+struct tlb_invalidate_info {
+	__u32	model;
+	__u8	opaque[];
+};
+
 #ifdef CONFIG_IOMMU_API
 
 /**
@@ -215,6 +220,8 @@ struct iommu_ops {
 				struct pasid_table_info *pasidt_binfo);
 	int (*unbind_pasid_table)(struct iommu_domain *domain,
 				struct device *dev);
+	int (*do_invalidate)(struct iommu_domain *domain,
+		struct device *dev, struct tlb_invalidate_info *inv_info);
 
 	unsigned long pgsize_bitmap;
 };
@@ -240,6 +247,9 @@ extern int iommu_bind_pasid_table(struct iommu_domain *domain,
 		struct device *dev, struct pasid_table_info *pasidt_binfo);
 extern int iommu_unbind_pasid_table(struct iommu_domain *domain,
 				struct device *dev);
+extern int iommu_do_invalidate(struct iommu_domain *domain,
+		struct device *dev, struct tlb_invalidate_info *inv_info);
+
 extern struct iommu_domain *iommu_get_domain_for_dev(struct device *dev);
 extern int iommu_map(struct iommu_domain *domain, unsigned long iova,
 		     phys_addr_t paddr, size_t size, int prot);
@@ -626,6 +636,12 @@ int iommu_unbind_pasid_table(struct iommu_domain *domain, struct device *dev)
 	return -EINVAL;
 }
 
+static inline int iommu_do_invalidate(struct iommu_domain *domain,
+		struct device *dev, struct tlb_invalidate_info *inv_info)
+{
+	return -EINVAL;
+}
+
 #endif /* CONFIG_IOMMU_API */
 
 #endif /* __LINUX_IOMMU_H */
-- 
1.9.1