[PATCH 7/8] iommu/amd: Add support for nested domain allocation

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

The child domain is allocated with IOMMU_DOMAIN_NESTED type to store
stage-1 translation (i.e. GVA->GPA). This includes the GCR3 root pointer
table along with guest (v2) page tables. The struct iommu_hwpt_amd_v2
contains this information, and is passed from user-space as a parameter
of the struct iommu_ops.domain_alloc_nested().

The parent domain is tracked using the struct protection_domain.parent.

Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
---
 drivers/iommu/amd/Makefile          |  2 +-
 drivers/iommu/amd/amd_iommu.h       |  5 ++
 drivers/iommu/amd/amd_iommu_types.h |  5 ++
 drivers/iommu/amd/iommu.c           | 22 ++++----
 drivers/iommu/amd/nested.c          | 79 +++++++++++++++++++++++++++++
 5 files changed, 103 insertions(+), 10 deletions(-)
 create mode 100644 drivers/iommu/amd/nested.c

diff --git a/drivers/iommu/amd/Makefile b/drivers/iommu/amd/Makefile
index 59c04a67f398..9ccf9d61810c 100644
--- a/drivers/iommu/amd/Makefile
+++ b/drivers/iommu/amd/Makefile
@@ -1,3 +1,3 @@
 # SPDX-License-Identifier: GPL-2.0-only
-obj-y += iommu.o init.o quirks.o io_pgtable.o io_pgtable_v2.o ppr.o pasid.o
+obj-y += iommu.o init.o quirks.o io_pgtable.o io_pgtable_v2.o ppr.o pasid.o nested.o
 obj-$(CONFIG_AMD_IOMMU_DEBUGFS) += debugfs.o
diff --git a/drivers/iommu/amd/amd_iommu.h b/drivers/iommu/amd/amd_iommu.h
index 3ff380afb9f4..8e86d5b1d915 100644
--- a/drivers/iommu/amd/amd_iommu.h
+++ b/drivers/iommu/amd/amd_iommu.h
@@ -8,6 +8,7 @@
 #define AMD_IOMMU_H
 
 #include <linux/iommu.h>
+#include <uapi/linux/iommufd.h>
 
 #include "amd_iommu_types.h"
 
@@ -190,4 +191,8 @@ void amd_iommu_domain_set_pgtable(struct protection_domain *domain,
 struct dev_table_entry *get_dev_table(struct amd_iommu *iommu);
 struct iommu_dev_data *search_dev_data(struct amd_iommu *iommu, u16 devid);
 
+/* NESTED */
+struct iommu_domain *
+amd_iommu_domain_alloc_nested(struct device *dev, struct iommu_domain *parent,
+			      u32 flags, const struct iommu_user_data *user_data);
 #endif /* AMD_IOMMU_H */
diff --git a/drivers/iommu/amd/amd_iommu_types.h b/drivers/iommu/amd/amd_iommu_types.h
index 5343b99913e4..94f51a09b364 100644
--- a/drivers/iommu/amd/amd_iommu_types.h
+++ b/drivers/iommu/amd/amd_iommu_types.h
@@ -20,6 +20,8 @@
 #include <linux/irqreturn.h>
 #include <linux/io-pgtable.h>
 
+#include <uapi/linux/iommufd.h>
+
 /*
  * Maximum number of IOMMUs supported
  */
@@ -605,6 +607,9 @@ struct protection_domain {
 
 	struct mmu_notifier mn;	/* mmu notifier for the SVA domain */
 	struct list_head dev_data_list; /* List of pdom_dev_data */
+
+	struct protection_domain *parent; /* Nested parent domain */
+	struct iommu_hwpt_amd_v2 guest_hwpt;
 };
 
 /*
diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c
index 46682c8ba28d..ea790a8997ee 100644
--- a/drivers/iommu/amd/iommu.c
+++ b/drivers/iommu/amd/iommu.c
@@ -2616,6 +2616,7 @@ amd_iommu_domain_alloc_paging_flags(struct device *dev, u32 flags,
 				    const struct iommu_user_data *user_data)
 
 {
+	struct iommu_domain *dom = ERR_PTR(-EOPNOTSUPP);
 	struct iommu_dev_data *dev_data = dev_iommu_priv_get(dev);
 	struct amd_iommu *iommu = get_amd_iommu_from_dev(dev);
 	const u32 supported_flags = IOMMU_HWPT_ALLOC_DIRTY_TRACKING |
@@ -2626,29 +2627,31 @@ amd_iommu_domain_alloc_paging_flags(struct device *dev, u32 flags,
 	if ((flags & ~supported_flags) || user_data || !is_nest_parent_supported(flags))
 		return ERR_PTR(-EOPNOTSUPP);
 
-	pr_debug("%s: IOMMU devid=%#x, flags=%#x\n", __func__, dev_data->devid, flags);
+	pr_debug("%s: IOMMU devid=%#x, flags=%#x, supported_flags=%#x\n", __func__, dev_data->devid, flags, supported_flags);
 
 	switch (flags & supported_flags) {
 	case IOMMU_HWPT_ALLOC_DIRTY_TRACKING:
 	case IOMMU_HWPT_ALLOC_DIRTY_TRACKING | IOMMU_HWPT_ALLOC_NEST_PARENT:
 	case IOMMU_HWPT_ALLOC_NEST_PARENT:
 		/* Allocate domain with v1 page table for dirty tracking */
-		if (!amd_iommu_hd_support(iommu))
-			break;
-		return do_iommu_domain_alloc(dev, flags, PD_MODE_V1);
+		if (amd_iommu_hd_support(iommu))
+			dom = do_iommu_domain_alloc(dev, flags, PD_MODE_V1);
+		break;
 	case IOMMU_HWPT_ALLOC_PASID:
 		/* Allocate domain with v2 page table if IOMMU supports PASID. */
-		if (!amd_iommu_pasid_supported())
-			break;
-		return do_iommu_domain_alloc(dev, flags, PD_MODE_V2);
+		if (amd_iommu_pasid_supported())
+			dom = do_iommu_domain_alloc(dev, flags, PD_MODE_V2);
+		break;
 	case 0:
 		/* If nothing specific is required use the kernel commandline default */
-		return do_iommu_domain_alloc(dev, 0, amd_iommu_pgtable);
+		dom = do_iommu_domain_alloc(dev, 0, amd_iommu_pgtable);
+		break;
 	default:
 		pr_err("%s: Unhandled flag : 0x%x\n", __func__, flags);
 		break;
 	}
-	return ERR_PTR(-EOPNOTSUPP);
+
+	return dom;
 }
 
 void amd_iommu_domain_free(struct iommu_domain *dom)
@@ -3113,6 +3116,7 @@ const struct iommu_ops amd_iommu_ops = {
 	.release_domain = &release_domain,
 	.identity_domain = &identity_domain.domain,
 	.domain_alloc_paging_flags = amd_iommu_domain_alloc_paging_flags,
+	.domain_alloc_nested = amd_iommu_domain_alloc_nested,
 	.domain_alloc_sva = amd_iommu_domain_alloc_sva,
 	.probe_device = amd_iommu_probe_device,
 	.release_device = amd_iommu_release_device,
diff --git a/drivers/iommu/amd/nested.c b/drivers/iommu/amd/nested.c
new file mode 100644
index 000000000000..09f2a455af33
--- /dev/null
+++ b/drivers/iommu/amd/nested.c
@@ -0,0 +1,79 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2023 Advanced Micro Devices, Inc.
+ */
+
+#define pr_fmt(fmt)     "AMD-Vi: " fmt
+#define dev_fmt(fmt)    pr_fmt(fmt)
+
+#include <linux/iommu.h>
+#include <uapi/linux/iommufd.h>
+
+#include "amd_iommu.h"
+#include "amd_iommu_types.h"
+
+const struct iommu_domain_ops nested_domain_ops = {
+	.free = amd_iommu_domain_free,
+};
+
+static int udata_to_iommu_hwpt_amd_v2(const struct iommu_user_data *user_data,
+				       struct iommu_hwpt_amd_v2 *hwpt)
+{
+	if (!user_data)
+		return -EINVAL;
+
+	if (user_data->type != IOMMU_HWPT_DATA_AMD_V2)
+		return -EOPNOTSUPP;
+
+	return iommu_copy_struct_from_user(hwpt, user_data,
+					   IOMMU_HWPT_DATA_AMD_V2,
+					   dte);
+}
+
+struct iommu_domain *
+amd_iommu_domain_alloc_nested(struct device *dev, struct iommu_domain *parent,
+			      u32 flags, const struct iommu_user_data *user_data)
+{
+	int ret;
+	struct iommu_hwpt_amd_v2 hwpt;
+	struct protection_domain *pdom;
+
+	if (parent->ops != amd_iommu_ops.default_domain_ops)
+		return ERR_PTR(-EINVAL);
+
+	ret = udata_to_iommu_hwpt_amd_v2(user_data, &hwpt);
+	if (ret)
+		return ERR_PTR(ret);
+
+	pdom = kzalloc(sizeof(*pdom), GFP_KERNEL);
+	if (IS_ERR(pdom))
+		return ERR_PTR(-ENOMEM);
+
+	pdom->id = amd_iommu_pdom_id_alloc();
+	if (!pdom->id)
+		goto out_err;
+
+	pr_debug("%s: Allocating nested domain with parent domid=%#x\n",
+		 __func__, to_pdomain(parent)->id);
+
+	spin_lock_init(&pdom->lock);
+	INIT_LIST_HEAD(&pdom->dev_list);
+	INIT_LIST_HEAD(&pdom->dev_data_list);
+	xa_init(&pdom->iommu_array);
+
+	pdom->pd_mode = PD_MODE_V2;
+	pdom->iop.pgtbl.cfg.amd.nid = NUMA_NO_NODE;
+	pdom->parent = to_pdomain(parent);
+	pdom->domain.ops = &nested_domain_ops;
+	pdom->domain.type = IOMMU_DOMAIN_NESTED;
+	pdom->domain.geometry.aperture_start = 0;
+	pdom->domain.geometry.aperture_end = ((1ULL << PM_LEVEL_SHIFT(amd_iommu_gpt_level)) - 1);
+	pdom->domain.geometry.force_aperture = true;
+	pdom->domain.pgsize_bitmap = pdom->iop.pgtbl.cfg.pgsize_bitmap;
+	memcpy(&pdom->guest_hwpt, &hwpt, sizeof(struct iommu_hwpt_amd_v2));
+
+	return &pdom->domain;
+out_err:
+	kfree(pdom);
+	return ERR_PTR(-EINVAL);
+}
-- 
2.34.1