[PATCH v5 05/24] iommu/amd: Allocate Guest IDs for IOMMUFD vIOMMU instances

[Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>]

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. Initialize gid_ida in init_iommu_one() and destroy it
in free_iommu_one() with the IOMMU object.

Reject amd_iommufd_viommu_init() with -EOPNOTSUPP when the IOMMU
does not have AMD_IOMMU_FLAG_VIOMMU_EN.

Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
---
 drivers/iommu/amd/amd_iommu.h       |  4 ++++
 drivers/iommu/amd/amd_iommu_types.h |  7 +++++++
 drivers/iommu/amd/init.c            |  2 ++
 drivers/iommu/amd/iommu.c           | 16 ++++++++++++++++
 drivers/iommu/amd/iommufd.c         | 14 ++++++++++++++
 5 files changed, 43 insertions(+)

diff --git a/drivers/iommu/amd/amd_iommu.h b/drivers/iommu/amd/amd_iommu.h
index b2ae17e3df34..f6cf412a9820 100644
--- a/drivers/iommu/amd/amd_iommu.h
+++ b/drivers/iommu/amd/amd_iommu.h
@@ -227,4 +227,8 @@ 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 688cd9240790..8c38775ff5c1 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>
 
@@ -404,6 +405,9 @@
 
 #define MAX_DOMAIN_ID 65536
 
+/* Guest ID bits 0-14; bit 15 is reserved for secure vIOMMU. */
+#define VIOMMU_MAX_GID		0x7FFF
+
 /* Timeout stuff */
 #define LOOP_TIMEOUT		100000
 #define MMIO_STATUS_TIMEOUT	2000000
@@ -501,6 +505,7 @@ 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.
@@ -760,6 +765,8 @@ struct amd_iommu {
 	/* IOPF support */
 	struct iopf_queue *iopf_queue;
 	unsigned char iopfq_name[32];
+
+	struct ida gid_ida;		 /* guest IDs for this IOMMU */
 };
 
 static inline struct amd_iommu *dev_to_amd_iommu(struct device *dev)
diff --git a/drivers/iommu/amd/init.c b/drivers/iommu/amd/init.c
index c80872ce0b60..7b4cb473019d 100644
--- a/drivers/iommu/amd/init.c
+++ b/drivers/iommu/amd/init.c
@@ -1797,6 +1797,7 @@ static void __init free_iommu_one(struct amd_iommu *iommu)
 	free_ga_log(iommu);
 	iommu_unmap_mmio_space(iommu);
 	amd_iommu_iopf_uninit(iommu);
+	ida_destroy(&iommu->gid_ida);
 }
 
 static void __init free_iommu_all(void)
@@ -1885,6 +1886,7 @@ static int __init init_iommu_one(struct amd_iommu *iommu, struct ivhd_header *h,
 
 	raw_spin_lock_init(&iommu->lock);
 	iommu->cmd_sem_val = 0;
+	ida_init(&iommu->gid_ida);
 
 	/* Add IOMMU to internal data structures */
 	list_add_tail(&iommu->list, &amd_iommu_list);
diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c
index c34a0f5a9540..fa9708af258e 100644
--- a/drivers/iommu/amd/iommu.c
+++ b/drivers/iommu/amd/iommu.c
@@ -257,6 +257,22 @@ 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_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 e8e7807f2a33..69a0e61bf83d 100644
--- a/drivers/iommu/amd/iommufd.c
+++ b/drivers/iommu/amd/iommufd.c
@@ -49,13 +49,23 @@ 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 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);
+
+	if (!amd_iommu_viommu_enabled(iommu))
+		return -EOPNOTSUPP;
 
 	xa_init_flags(&aviommu->gdomid_array, XA_FLAGS_ALLOC1);
 	aviommu->parent = pdom;
 
+	ret = amd_iommu_gid_alloc(iommu);
+	if (ret < 0)
+		return ret;
+	aviommu->gid = ret;
+
 	viommu->ops = &amd_viommu_ops;
 
 	spin_lock_irqsave(&pdom->lock, flags);
@@ -70,11 +80,15 @@ 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