[RFC PATCH 21/45] KVM: arm64: iommu: Add SMMUv3 driver

[Jean-Philippe Brucker]

Add the skeleton for an Arm SMMUv3 driver at EL2.

Signed-off-by: Jean-Philippe Brucker <jean-philippe at linaro.org>
---
 drivers/iommu/Kconfig                       | 10 ++++++++
 arch/arm64/kvm/hyp/nvhe/Makefile            |  1 +
 arch/arm64/include/asm/kvm_host.h           |  1 +
 arch/arm64/kvm/hyp/include/nvhe/iommu.h     |  9 +++++++
 include/kvm/arm_smmu_v3.h                   | 22 +++++++++++++++++
 arch/arm64/kvm/hyp/nvhe/iommu/arm-smmu-v3.c | 27 +++++++++++++++++++++
 arch/arm64/kvm/hyp/nvhe/setup.c             |  2 ++
 7 files changed, 72 insertions(+)
 create mode 100644 include/kvm/arm_smmu_v3.h
 create mode 100644 arch/arm64/kvm/hyp/nvhe/iommu/arm-smmu-v3.c

diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
index 79707685d54a..1689d416ccd8 100644
--- a/drivers/iommu/Kconfig
+++ b/drivers/iommu/Kconfig
@@ -410,6 +410,16 @@ config ARM_SMMU_V3_SVA
 	  Say Y here if your system supports SVA extensions such as PCIe PASID
 	  and PRI.
 
+config ARM_SMMU_V3_PKVM
+	bool "ARM SMMUv3 support for protected Virtual Machines"
+	depends on KVM && ARM64
+	select KVM_IOMMU
+	help
+	  Enable a SMMUv3 driver in the KVM hypervisor, to protect VMs against
+	  memory accesses from devices owned by the host.
+
+	  Say Y here if you intend to enable KVM in protected mode.
+
 config S390_IOMMU
 	def_bool y if S390 && PCI
 	depends on S390 && PCI
diff --git a/arch/arm64/kvm/hyp/nvhe/Makefile b/arch/arm64/kvm/hyp/nvhe/Makefile
index f7dfc88c9f5b..349c874762c8 100644
--- a/arch/arm64/kvm/hyp/nvhe/Makefile
+++ b/arch/arm64/kvm/hyp/nvhe/Makefile
@@ -29,6 +29,7 @@ hyp-obj-$(CONFIG_DEBUG_LIST) += list_debug.o
 hyp-obj-y += $(lib-objs)
 
 hyp-obj-$(CONFIG_KVM_IOMMU) += iommu/iommu.o
+hyp-obj-$(CONFIG_ARM_SMMU_V3_PKVM) += iommu/arm-smmu-v3.o
 
 ##
 ## Build rules for compiling nVHE hyp code
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index b8e032bda022..c98ce17f8148 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -379,6 +379,7 @@ extern u64 kvm_nvhe_sym(hyp_cpu_logical_map)[NR_CPUS];
 
 enum kvm_iommu_driver {
 	KVM_IOMMU_DRIVER_NONE,
+	KVM_IOMMU_DRIVER_SMMUV3,
 };
 
 struct vcpu_reset_state {
diff --git a/arch/arm64/kvm/hyp/include/nvhe/iommu.h b/arch/arm64/kvm/hyp/include/nvhe/iommu.h
index 76d3fa6ce331..0ba59d20bef3 100644
--- a/arch/arm64/kvm/hyp/include/nvhe/iommu.h
+++ b/arch/arm64/kvm/hyp/include/nvhe/iommu.h
@@ -5,6 +5,15 @@
 #include <kvm/iommu.h>
 #include <linux/io-pgtable.h>
 
+#if IS_ENABLED(CONFIG_ARM_SMMU_V3_PKVM)
+int kvm_arm_smmu_v3_register(void);
+#else /* CONFIG_ARM_SMMU_V3_PKVM */
+static inline int kvm_arm_smmu_v3_register(void)
+{
+	return -EINVAL;
+}
+#endif /* CONFIG_ARM_SMMU_V3_PKVM */
+
 #if IS_ENABLED(CONFIG_KVM_IOMMU)
 int kvm_iommu_init(void);
 int kvm_iommu_init_device(struct kvm_hyp_iommu *iommu);
diff --git a/include/kvm/arm_smmu_v3.h b/include/kvm/arm_smmu_v3.h
new file mode 100644
index 000000000000..ebe488b2f93c
--- /dev/null
+++ b/include/kvm/arm_smmu_v3.h
@@ -0,0 +1,22 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __KVM_ARM_SMMU_V3_H
+#define __KVM_ARM_SMMU_V3_H
+
+#include <asm/kvm_asm.h>
+#include <kvm/iommu.h>
+
+#if IS_ENABLED(CONFIG_ARM_SMMU_V3_PKVM)
+
+struct hyp_arm_smmu_v3_device {
+	struct kvm_hyp_iommu	iommu;
+};
+
+extern size_t kvm_nvhe_sym(kvm_hyp_arm_smmu_v3_count);
+#define kvm_hyp_arm_smmu_v3_count kvm_nvhe_sym(kvm_hyp_arm_smmu_v3_count)
+
+extern struct hyp_arm_smmu_v3_device *kvm_nvhe_sym(kvm_hyp_arm_smmu_v3_smmus);
+#define kvm_hyp_arm_smmu_v3_smmus kvm_nvhe_sym(kvm_hyp_arm_smmu_v3_smmus)
+
+#endif /* CONFIG_ARM_SMMU_V3_PKVM */
+
+#endif /* __KVM_ARM_SMMU_V3_H */
diff --git a/arch/arm64/kvm/hyp/nvhe/iommu/arm-smmu-v3.c b/arch/arm64/kvm/hyp/nvhe/iommu/arm-smmu-v3.c
new file mode 100644
index 000000000000..c167e4dbd28d
--- /dev/null
+++ b/arch/arm64/kvm/hyp/nvhe/iommu/arm-smmu-v3.c
@@ -0,0 +1,27 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * pKVM hyp driver for the Arm SMMUv3
+ *
+ * Copyright (C) 2022 Linaro Ltd.
+ */
+#include <asm/kvm_hyp.h>
+#include <kvm/arm_smmu_v3.h>
+#include <nvhe/iommu.h>
+
+size_t __ro_after_init kvm_hyp_arm_smmu_v3_count;
+struct hyp_arm_smmu_v3_device __ro_after_init *kvm_hyp_arm_smmu_v3_smmus;
+
+static int smmu_init(void)
+{
+	return -ENOSYS;
+}
+
+static struct kvm_iommu_ops smmu_ops = {
+	.init				= smmu_init,
+};
+
+int kvm_arm_smmu_v3_register(void)
+{
+	kvm_iommu_ops = smmu_ops;
+	return 0;
+}
diff --git a/arch/arm64/kvm/hyp/nvhe/setup.c b/arch/arm64/kvm/hyp/nvhe/setup.c
index 3e73c066d560..a25de8c5d489 100644
--- a/arch/arm64/kvm/hyp/nvhe/setup.c
+++ b/arch/arm64/kvm/hyp/nvhe/setup.c
@@ -294,6 +294,8 @@ static int select_iommu_ops(enum kvm_iommu_driver driver)
 	switch (driver) {
 	case KVM_IOMMU_DRIVER_NONE:
 		return 0;
+	case KVM_IOMMU_DRIVER_SMMUV3:
+		return kvm_arm_smmu_v3_register();
 	}
 
 	return -EINVAL;
-- 
2.39.0