[PATCH v2 05/26] iommu/amd: Allocate Guest IDs for IOMMUFD vIOMMU instances

[Suravee Suthikulpanit]

Hardware vIOMMU uses a 16-bit Guest ID (GID) per guest IOMMU to
index driver and hardware state. Allocate one GID per IOMMUFD vIOMMU
from a per-amd_iommu IDA (unique within that IOMMU; a VM behind
multiple IOMMUs may hold more than one GID).

Add amd_iommu_gid_alloc() and amd_iommu_gid_free(), store the ID in
amd_iommu_viommu::gid, and call them from amd_iommufd_viommu_init() and
destroy after copying struct iommu_viommu_amd to userspace.

ida_init() for gid_ida is done when vIOMMU MMIO is mapped (next patch).

Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@xxxxxxx>
---
 drivers/iommu/amd/amd_iommu.h       |  4 ++++
 drivers/iommu/amd/amd_iommu_types.h |  8 ++++++++
 drivers/iommu/amd/iommu.c           | 19 +++++++++++++++++
 drivers/iommu/amd/iommufd.c         | 32 +++++++++++++++++++++++++++++
 4 files changed, 63 insertions(+)

diff --git a/drivers/iommu/amd/amd_iommu.h b/drivers/iommu/amd/amd_iommu.h
index 17fc0b5b3fa8..9f2a1a8a6d3c 100644
--- a/drivers/iommu/amd/amd_iommu.h
+++ b/drivers/iommu/amd/amd_iommu.h
@@ -228,4 +228,8 @@ 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(struct amd_iommu *iommu);
+void amd_iommu_gid_free(struct amd_iommu *iommu, 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 b5327bf6814b..00f964d5b149 100644
--- a/drivers/iommu/amd/amd_iommu_types.h
+++ b/drivers/iommu/amd/amd_iommu_types.h
@@ -21,6 +21,7 @@
 #include <linux/iommufd.h>
 #include <linux/irqreturn.h>
 #include <linux/generic_pt/iommu.h>
+#include <linux/idr.h>
 
 #include <uapi/linux/iommufd.h>
 
@@ -413,6 +414,9 @@
 
 #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 +513,7 @@ 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.
@@ -768,6 +773,9 @@ struct amd_iommu {
 	/* IOPF support */
 	struct iopf_queue *iopf_queue;
 	unsigned char iopfq_name[32];
+
+	struct ida gid_ida;		 /* guest IDs for this IOMMU */
+	bool gid_ida_inited;
 };
 
 static inline struct amd_iommu *dev_to_amd_iommu(struct device *dev)
diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c
index 50f26c8123f3..73fba8be40d1 100644
--- a/drivers/iommu/amd/iommu.c
+++ b/drivers/iommu/amd/iommu.c
@@ -252,6 +252,25 @@ 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(struct amd_iommu *iommu)
+{
+	int ret = ida_alloc_range(&iommu->gid_ida, 1, VIOMMU_MAX_GID, GFP_KERNEL);
+
+	if (ret < 0)
+		pr_err("%s: Failed to allocate guest ID (devid=%#x)\n",
+		       __func__, iommu->devid);
+	else
+		pr_debug("%s: iommu devid=%#x, gid=%u\n", __func__, iommu->devid, ret);
+
+	return ret;
+}
+
+void amd_iommu_gid_free(struct amd_iommu *iommu, int gid)
+{
+	pr_debug("%s: iommu devid=%#x, gid=%u\n", __func__, iommu->devid, gid);
+	ida_free(&iommu->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 eee29c26169a..785fa2d575f2 100644
--- a/drivers/iommu/amd/iommufd.c
+++ b/drivers/iommu/amd/iommufd.c
@@ -43,13 +43,37 @@ 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);
+	struct amd_iommu *iommu = container_of(viommu->iommu_dev, struct amd_iommu, iommu);
 
 	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;
+
+	ret = amd_iommu_gid_alloc(iommu);
+	if (ret < 0)
+		goto err_gid;
+	aviommu->gid = ret;
+	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_init;
+
 	viommu->ops = &amd_viommu_ops;
 
 	spin_lock_irqsave(&pdom->lock, flags);
@@ -57,6 +81,10 @@ int amd_iommufd_viommu_init(struct iommufd_viommu *viommu, struct iommu_domain *
 	spin_unlock_irqrestore(&pdom->lock, flags);
 
 	return 0;
+err_init:
+	amd_iommu_gid_free(iommu, aviommu->gid);
+err_gid:
+	return ret;
 }
 
 static void amd_iommufd_viommu_destroy(struct iommufd_viommu *viommu)
@@ -64,11 +92,15 @@ 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(iommu, aviommu->gid);
 }
 
 /*
-- 
2.34.1