IOMMU: Add backend support for IOMMU

Cargo.toml

@@ -12,12 +12,12 @@ members = [
 ]
 
 [workspace.dependencies.sel4-capdl-initializer]
-git = "https://github.com/seL4/rust-sel4"
-rev = "2541371f62dd097f7d47127125c44a0922145fa5"
+git = "https://github.com/au-ts/rust-sel4"
+rev = "121798b0260d0ff5ca1185702a0d3285d01ef439"
 
 [workspace.dependencies.sel4-capdl-initializer-types]
-git = "https://github.com/seL4/rust-sel4"
-rev = "2541371f62dd097f7d47127125c44a0922145fa5"
+git = "https://github.com/au-ts/rust-sel4"
+rev = "121798b0260d0ff5ca1185702a0d3285d01ef439"
 
 [profile.release.package.microkit-tool]
 strip = true

build_sdk.py

@@ -67,8 +67,7 @@
 DEFAULT_KERNEL_OPTIONS_X86_64 = {
     "KernelPlatform": "pc99",
     "KernelX86MicroArch": "generic",
-    # See https://github.com/seL4/microkit/issues/418 for details.
-    "KernelIOMMU": False,
+    "KernelIOMMU": True,
 } | DEFAULT_KERNEL_OPTIONS
 
 

example/x86_64_iommu_dma_test/Makefile

@@ -0,0 +1,72 @@
+#
+# Copyright 2026, UNSW
+#
+# SPDX-License-Identifier: BSD-2-Clause
+#
+ifeq ($(strip $(BUILD_DIR)),)
+$(error BUILD_DIR must be specified)
+endif
+
+ifeq ($(strip $(MICROKIT_SDK)),)
+$(error MICROKIT_SDK must be specified)
+endif
+
+ifeq ($(strip $(MICROKIT_BOARD)),)
+$(error MICROKIT_BOARD must be specified)
+endif
+
+ifeq ($(strip $(MICROKIT_CONFIG)),)
+$(error MICROKIT_CONFIG must be specified)
+endif
+
+BOARD_DIR := $(MICROKIT_SDK)/board/$(MICROKIT_BOARD)/$(MICROKIT_CONFIG)
+
+ARCH := ${shell grep 'CONFIG_SEL4_ARCH  ' $(BOARD_DIR)/include/kernel/gen_config.h | cut -d' ' -f4}
+
+ifeq ($(ARCH),x86_64)
+	TOOLCHAIN := x86_64-linux-gnu
+	CFLAGS_ARCH := -march=x86-64 -mtune=generic
+else
+$(error Unsupported ARCH)
+endif
+
+CC := $(TOOLCHAIN)-gcc
+LD := $(TOOLCHAIN)-ld
+AS := $(TOOLCHAIN)-as
+OBJCOPY := $(TOOLCHAIN)-objcopy
+MICROKIT_TOOL ?= $(MICROKIT_SDK)/bin/microkit
+
+IMAGES := x86_64_iommu_dma_test.elf
+CFLAGS := -nostdlib -ffreestanding -g3 -O3 -I$(BOARD_DIR)/include $(CFLAGS_ARCH)
+LDFLAGS := -L$(BOARD_DIR)/lib -z noexecstack
+LIBS := -lmicrokit -Tmicrokit.ld
+
+INITIAL_TASK = $(BUILD_DIR)/initialiser.elf
+KERNEL = $(BUILD_DIR)/sel4.elf
+KERNEL_32B = $(BUILD_DIR)/sel4_32.elf
+REPORT = $(BUILD_DIR)/report.txt
+SPEC = $(BUILD_DIR)/capdl_spec.json
+
+all: $(KERNEL) $(INITIAL_TASK)
+qemu: $(KERNEL_32B) $(INITIAL_TASK)
+
+$(BUILD_DIR)/x86_64_iommu_dma_test.o: x86_64_iommu_dma_test.c Makefile
+	$(CC) -c $(CFLAGS) $< -o $@
+
+$(BUILD_DIR)/x86_64_iommu_dma_test.elf: $(BUILD_DIR)/x86_64_iommu_dma_test.o
+	$(LD) $(LDFLAGS) $^ $(LIBS) -o $@
+
+$(KERNEL) $(KERNEL_32B) $(INITIAL_TASK): $(addprefix $(BUILD_DIR)/, $(IMAGES)) x86_64_iommu_dma_test.system
+	$(MICROKIT_TOOL) x86_64_iommu_dma_test.system --search-path $(BUILD_DIR) --board $(MICROKIT_BOARD) --config $(MICROKIT_CONFIG) -o $(INITIAL_TASK) -r $(REPORT) --capdl-json $(SPEC)
+
+qemu:
+	qemu-system-x86_64                                      				\
+			-machine q35                                  					\
+			-cpu qemu64,+fsgsbase,+pdpe1gb,+xsaveopt,+xsave 				\
+			-m "4G"                                      					\
+			-display none                                					\
+			-serial mon:stdio                            					\
+			-device intel-iommu,intremap=off,aw-bits=39      				\
+			-device edu,dma_mask=0xffffffffffffffff,bus=pcie.0,addr=0x04.0  \
+		-kernel $(KERNEL_32B)                             					\
+		-initrd $(INITIAL_TASK)

example/x86_64_iommu_dma_test/README.md

@@ -0,0 +1,25 @@
+<!--
+     Copyright 2026, UNSW
+     SPDX-License-Identifier: CC-BY-SA-4.0
+-->
+# x86_64_iommu_dma_test
+
+This example checks x86 IOMMU mappings with QEMU's EDU PCI device. It maps one
+RAM page into the EDU device's IOSpace, asks the device to DMA from that page
+into its internal SRAM, then asks the device to DMA the SRAM contents back into
+a second offset in the same RAM page and verifies the data.
+
+The QEMU command in the Makefile pins the EDU device at PCI BDF `00:04.0`, which
+must match the `pcidev="0:4.0"` attribute in the system description.
+
+To build and run:
+
+```sh
+mkdir build
+make -C example/x86_64_iommu_dma_test \
+    BUILD_DIR=build \
+    MICROKIT_SDK=/path/to/microkit-sdk \
+    MICROKIT_BOARD=x86_64_generic \
+    MICROKIT_CONFIG=debug \
+    qemu
+```