[PATCH 05/10] iommu/ioasid: Create an IOASID set for host SVA use

[Jacob Pan]

Bare metal SVA allocates IOASIDs for native process addresses. This
should be separated from VM allocated IOASIDs thus under its own set.

This patch creates a system IOASID set with its quota set to PID_MAX.
This is a reasonable default in that SVM capable devices can only bind
to limited user processes.

Signed-off-by: Jacob Pan <jacob.jun.pan@xxxxxxxxxxxxxxx>
---
 drivers/iommu/intel-iommu.c | 8 +++++++-
 drivers/iommu/ioasid.c      | 9 +++++++++
 include/linux/ioasid.h      | 9 +++++++++
 3 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index ec3fc121744a..af7a1ef7b31e 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -3511,8 +3511,14 @@ static int __init init_dmars(void)
 		goto free_iommu;
 
 	/* PASID is needed for scalable mode irrespective to SVM */
-	if (intel_iommu_sm)
+	if (intel_iommu_sm) {
 		ioasid_install_capacity(intel_pasid_max_id);
+		/* We should not run out of IOASIDs at boot */
+		if (ioasid_alloc_system_set(PID_MAX_DEFAULT)) {
+			pr_err("Failed to enable host PASID allocator\n");
+			intel_iommu_sm = 0;
+		}
+	}
 
 	/*
 	 * for each drhd
diff --git a/drivers/iommu/ioasid.c b/drivers/iommu/ioasid.c
index 6265d2dbbced..9135af171a7c 100644
--- a/drivers/iommu/ioasid.c
+++ b/drivers/iommu/ioasid.c
@@ -39,6 +39,9 @@ struct ioasid_data {
 static ioasid_t ioasid_capacity;
 static ioasid_t ioasid_capacity_avail;
 
+int system_ioasid_sid;
+static DECLARE_IOASID_SET(system_ioasid);
+
 /* System capacity can only be set once */
 void ioasid_install_capacity(ioasid_t total)
 {
@@ -51,6 +54,12 @@ void ioasid_install_capacity(ioasid_t total)
 }
 EXPORT_SYMBOL_GPL(ioasid_install_capacity);
 
+int ioasid_alloc_system_set(int quota)
+{
+	return ioasid_alloc_set(&system_ioasid, quota, &system_ioasid_sid);
+}
+EXPORT_SYMBOL_GPL(ioasid_alloc_system_set);
+
 /*
  * struct ioasid_allocator_data - Internal data structure to hold information
  * about an allocator. There are two types of allocators:
diff --git a/include/linux/ioasid.h b/include/linux/ioasid.h
index 8c82d2625671..097b1cc043a3 100644
--- a/include/linux/ioasid.h
+++ b/include/linux/ioasid.h
@@ -29,6 +29,9 @@ struct ioasid_allocator_ops {
 	void *pdata;
 };
 
+/* Shared IOASID set for reserved for host system use */
+extern int system_ioasid_sid;
+
 #define DECLARE_IOASID_SET(name) struct ioasid_set name = { 0 }
 
 #if IS_ENABLED(CONFIG_IOASID)
@@ -41,6 +44,7 @@ int ioasid_register_allocator(struct ioasid_allocator_ops *allocator);
 void ioasid_unregister_allocator(struct ioasid_allocator_ops *allocator);
 int ioasid_attach_data(ioasid_t ioasid, void *data);
 void ioasid_install_capacity(ioasid_t total);
+int ioasid_alloc_system_set(int quota);
 int ioasid_alloc_set(struct ioasid_set *token, ioasid_t quota, int *sid);
 void ioasid_free_set(int sid, bool destroy_set);
 int ioasid_find_sid(ioasid_t ioasid);
@@ -88,5 +92,10 @@ static inline void ioasid_install_capacity(ioasid_t total)
 {
 }
 
+static inline int ioasid_alloc_system_set(int quota)
+{
+	return -ENOTSUPP;
+}
+
 #endif /* CONFIG_IOASID */
 #endif /* __LINUX_IOASID_H */
-- 
2.7.4