AMD HW-vIOMMU feature requires IOMMU driver to specify a unique 16-bit
Guest ID (GID) for each VM. This ID is per-vIOMMU instance, and it is used
to index into various data structures for configuring the hardware.

Introduce helper functions amd_iommu_gid_alloc() / amd_iommu_gid_free(),
which will be called during vIOMMU initialize/destroy.

Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
---
 drivers/iommu/amd/amd_iommu.h       |  4 ++++
 drivers/iommu/amd/amd_iommu_types.h |  4 ++++
 drivers/iommu/amd/iommu.c           | 20 ++++++++++++++++++++
 drivers/iommu/amd/iommufd.c         | 29 +++++++++++++++++++++++++++++
 4 files changed, 57 insertions(+)

diff --git a/drivers/iommu/amd/amd_iommu.h b/drivers/iommu/amd/amd_iommu.h
index c440f2745b38..51a7c3b3329f 100644
--- a/drivers/iommu/amd/amd_iommu.h
+++ b/drivers/iommu/amd/amd_iommu.h
@@ -226,4 +226,8 @@ amd_iommu_make_clear_dte(struct iommu_dev_data *dev_data, struct dev_table_entry
 struct iommu_domain *
 amd_iommu_alloc_domain_nested(struct iommufd_viommu *viommu, u32 flags,
 			      const struct iommu_user_data *user_data);
+
+/* Guest ID for vIOMMU */
+int amd_iommu_gid_alloc(void);
+void amd_iommu_gid_free(int gid);
 #endif /* AMD_IOMMU_H */
diff --git a/drivers/iommu/amd/amd_iommu_types.h b/drivers/iommu/amd/amd_iommu_types.h
index c5f779d76fc4..0b4d713d3337 100644
--- a/drivers/iommu/amd/amd_iommu_types.h
+++ b/drivers/iommu/amd/amd_iommu_types.h
@@ -413,6 +413,9 @@
 
 #define MAX_DOMAIN_ID 65536
 
+/* For vIOMMU, the GID is 16-bit. */
+#define VIOMMU_MAX_GID		0xFFFF
+
 /* Timeout stuff */
 #define LOOP_TIMEOUT		100000
 #define MMIO_STATUS_TIMEOUT	2000000
@@ -509,6 +512,7 @@ struct amd_iommu_viommu {
 	struct iommufd_viommu core;
 	struct protection_domain *parent; /* nest parent domain for this viommu */
 	struct list_head pdom_list;	  /* For protection_domain->viommu_list */
+	u16 gid;			  /* Guest ID for the vIOMMU */
 
 	/*
 	 * Per-vIOMMU guest domain ID to host domain ID mapping.
diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c
index d1f997b9a90b..037a50397f31 100644
--- a/drivers/iommu/amd/iommu.c
+++ b/drivers/iommu/amd/iommu.c
@@ -61,6 +61,9 @@ LIST_HEAD(acpihid_map);
 
 const struct iommu_ops amd_iommu_ops;
 
+/* Global guest ID */
+static DEFINE_IDA(amd_iommu_global_gid_ida);
+
 int amd_iommu_max_glx_val = -1;
 
 /*
@@ -252,6 +255,23 @@ static inline bool pdom_is_sva_capable(struct protection_domain *pdom)
 	return pdom_is_v2_pgtbl_mode(pdom) || pdom_is_in_pt_mode(pdom);
 }
 
+int amd_iommu_gid_alloc(void)
+{
+	int ret = ida_alloc_range(&amd_iommu_global_gid_ida, 1, VIOMMU_MAX_GID, GFP_KERNEL);
+
+	if (ret < 0)
+		pr_err("%s: Failed to allocate guest ID\n", __func__);
+	else
+		pr_debug("%s: gid=%u\n", __func__, ret);
+
+	return ret;
+}
+
+void amd_iommu_gid_free(int gid)
+{
+	ida_free(&amd_iommu_global_gid_ida, gid);
+}
+
 static inline int get_acpihid_device_id(struct device *dev,
 					struct acpihid_map_entry **entry)
 {
diff --git a/drivers/iommu/amd/iommufd.c b/drivers/iommu/amd/iommufd.c
index e7ffa7e8915b..6fba5d9b1310 100644
--- a/drivers/iommu/amd/iommufd.c
+++ b/drivers/iommu/amd/iommufd.c
@@ -43,13 +43,35 @@ size_t amd_iommufd_get_viommu_size(struct device *dev, enum iommu_viommu_type vi
 int amd_iommufd_viommu_init(struct iommufd_viommu *viommu, struct iommu_domain *parent,
 			    const struct iommu_user_data *user_data)
 {
+	int ret;
 	unsigned long flags;
+	struct iommu_viommu_amd data;
 	struct protection_domain *pdom = to_pdomain(parent);
 	struct amd_iommu_viommu *aviommu = container_of(viommu, struct amd_iommu_viommu, core);
 
 	xa_init_flags(&aviommu->gdomid_array, XA_FLAGS_ALLOC1);
 	aviommu->parent = pdom;
 
+	if (!user_data)
+		return -EINVAL;
+
+	ret = iommu_copy_struct_from_user(&data, user_data,
+					  IOMMU_VIOMMU_TYPE_AMD,
+					  reserved);
+	if (ret)
+		return ret;
+
+	aviommu->gid = amd_iommu_gid_alloc();
+	if (aviommu->gid < 0)
+		return aviommu->gid;
+	pr_debug("%s: gid=%#x", __func__, aviommu->gid);
+
+	ret = iommu_copy_struct_to_user(user_data, &data,
+					IOMMU_VIOMMU_TYPE_AMD,
+					reserved);
+	if (ret)
+		goto err_out;
+
 	viommu->ops = &amd_viommu_ops;
 
 	spin_lock_irqsave(&pdom->lock, flags);
@@ -57,6 +79,9 @@ int amd_iommufd_viommu_init(struct iommufd_viommu *viommu, struct iommu_domain *
 	spin_unlock_irqrestore(&pdom->lock, flags);
 
 	return 0;
+err_out:
+	amd_iommu_gid_free(aviommu->gid);
+	return ret;
 }
 
 static void amd_iommufd_viommu_destroy(struct iommufd_viommu *viommu)
@@ -64,11 +89,15 @@ static void amd_iommufd_viommu_destroy(struct iommufd_viommu *viommu)
 	unsigned long flags;
 	struct amd_iommu_viommu *aviommu = container_of(viommu, struct amd_iommu_viommu, core);
 	struct protection_domain *pdom = aviommu->parent;
+	struct amd_iommu *iommu = container_of(viommu->iommu_dev, struct amd_iommu, iommu);
+
+	pr_debug("%s: gid=%#x, iommu devid=%#x\n", __func__, aviommu->gid, iommu->devid);
 
 	spin_lock_irqsave(&pdom->lock, flags);
 	list_del(&aviommu->pdom_list);
 	spin_unlock_irqrestore(&pdom->lock, flags);
 	xa_destroy(&aviommu->gdomid_array);
+	amd_iommu_gid_free(aviommu->gid);
 }
 
 /*
-- 
2.34.1