BACKPORT: FROMLIST: KVM: arm64: iommu: Add SMMUv3 driver

Add the skeleton for an Arm SMMUv3 driver at EL2.

Link: https://lore.kernel.org/all/20241212180423.1578358-26-smostafa@google.com/

Bug: 357781595
Bug: 384432312

Change-Id: I605da2ed3075054b142eac6f6a7922f140244ca8
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Signed-off-by: Mostafa Saleh <smostafa@google.com>

arch/arm64/kvm/hyp/nvhe/Makefile

@@ -16,6 +16,8 @@ hyp-obj-$(CONFIG_TRACING) += clock.o events.o trace.o
 hyp-obj-$(CONFIG_MODULES) += modules.o
 hyp-obj-y += $(lib-objs)
 
+hyp-obj-$(CONFIG_ARM_SMMU_V3_PKVM) += iommu/arm-smmu-v3.o
+
 $(obj)/hyp.lds: $(src)/hyp.lds.S FORCE
 	$(call if_changed_dep,cpp_lds_S)
 

arch/arm64/kvm/hyp/nvhe/iommu/arm-smmu-v3.c

@@ -0,0 +1,22 @@
+// 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 *kvm_hyp_arm_smmu_v3_smmus;
+
+static int smmu_init(void)
+{
+	return -ENOSYS;
+}
+
+/* Shared with the kernel driver in EL1 */
+struct kvm_iommu_ops smmu_ops = {
+	.init				= smmu_init,
+};

drivers/iommu/Kconfig

@@ -437,6 +437,15 @@ config TEGRA241_CMDQV
 	  CMDQ-V extension.
 endif
 
+config ARM_SMMU_V3_PKVM
+	bool "ARM SMMUv3 support for protected Virtual Machines"
+	depends on KVM && ARM64
+	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

include/kvm/arm_smmu_v3.h

@@ -0,0 +1,18 @@
+/* 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>
+
+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 /* __KVM_ARM_SMMU_V3_H */