KO: add a simple linux kernel module

examples/ko/.clang-format

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+---
+Language: Cpp
+BasedOnStyle: LLVM
+IndentWidth: 4
+ColumnLimit: 120
+AllowShortIfStatementsOnASingleLine: true
+AllowShortBlocksOnASingleLine: Empty
+AlignConsecutiveMacros: true
+PointerAlignment: Left
+---

examples/ko/.gitignore

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+.*.cmd
+*.a
+*.ko
+*.o
+*.mod.c
+*.mod
+Module.symvers
+modules.order

examples/ko/Makefile

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+export KDIR ?= /lib/modules/$(shell uname -r)/build
+
+module := rvm
+
+ccflags-y := -I$(src)/include
+obj-m += rvm.o
+
+all: build
+
+build:
+ $(MAKE) -C $(KDIR) M=$(PWD) CC=$(CC)
+
+clean:
+ $(MAKE) -C $(KDIR) M=$(PWD) CC=$(CC) clean
+
+insmod: rmmod
+ sudo dmesg -C
+ sudo insmod $(module).ko
+ sudo chown root:kvm /dev/rvm
+ sudo chmod 660 /dev/rvm
+ dmesg
+
+rmmod:
+ifneq ($(shell lsmod | grep rvm),)
+ sudo rmmod $(module)
+endif
+
+test: rmmod
+ sudo dmesg -C
+ sudo insmod $(module).ko
+ sudo rmmod $(module).ko
+ dmesg

examples/ko/include/rvm.h

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+#ifndef RVM_H
+#define RVM_H
+
+#include <linux/types.h>
+
+#define RVM_IO 0xAE00
+#define RVM_GUEST_CREATE (RVM_IO + 0x01)
+#define RVM_GUEST_ADD_MEMORY_REGION (RVM_IO + 0x02)
+#define RVM_GUEST_SET_TRAP (RVM_IO + 0x03)
+#define RVM_VCPU_CREATE (RVM_IO + 0x11)
+#define RVM_VCPU_RESUME (RVM_IO + 0x12)
+#define RVM_VCPU_READ_STATE (RVM_IO + 0x13)
+#define RVM_VCPU_WRITE_STATE (RVM_IO + 0x14)
+#define RVM_VCPU_INTERRUPT (RVM_IO + 0x15)
+
+enum rvm_trap_kind {
+ RVM_TRAP_KIND_BELL = 0,
+ RVM_TRAP_KIND_MEM = 1,
+ RVM_TRAP_KIND_IO = 2,
+};
+
+enum rvm_exit_packet_kind {
+ RVM_EXIT_PKT_KIND_GUEST_BELL = 1,
+ RVM_EXIT_PKT_KIND_GUEST_IO = 2,
+ RVM_EXIT_PKT_KIND_GUEST_MMIO = 3,
+ RVM_EXIT_PKT_KIND_GUEST_VCPU = 4,
+};
+
+enum rvm_vcpu_read_write_kind {
+ RVM_VCPU_STATE = 0,
+ RVM_VCPU_IO = 1,
+};
+
+struct rvm_vcpu_state {
+ uint64_t rax;
+ uint64_t rcx;
+ uint64_t rdx;
+ uint64_t rbx;
+ uint64_t rsp;
+ uint64_t rbp;
+ uint64_t rsi;
+ uint64_t rdi;
+ uint64_t r8;
+ uint64_t r9;
+ uint64_t r10;
+ uint64_t r11;
+ uint64_t r12;
+ uint64_t r13;
+ uint64_t r14;
+ uint64_t r15;
+ // Contains only the user-controllable lower 32-bits.
+ uint64_t rflags;
+};
+
+typedef struct rvm_io_value rvm_vcpu_io;
+
+struct rvm_io_value {
+ uint8_t access_size;
+ union {
+ uint8_t u8;
+ uint16_t u16;
+ uint32_t u32;
+ uint8_t buf[4];
+ };
+};
+
+struct rvm_exit_io_packet {
+ uint16_t port;
+ uint8_t access_size;
+ bool is_input;
+ bool is_string;
+ bool is_repeat;
+ union {
+ uint8_t u8;
+ uint16_t u16;
+ uint32_t u32;
+ uint8_t buf[4];
+ };
+};
+
+struct rvm_exit_mmio_packet {
+ uint64_t addr;
+ uint8_t inst_len;
+ uint8_t inst_buf[15];
+ uint8_t default_operand_size;
+};
+
+struct rvm_exit_packet {
+ enum rvm_exit_packet_kind kind;
+ uint64_t key;
+ union {
+ struct rvm_exit_io_packet io;
+ struct rvm_exit_mmio_packet mmio;
+ };
+};
+
+struct rvm_guest_add_memory_region_args {
+ uint16_t vmid;
+ uint64_t guest_start_paddr;
+ uint64_t memory_size;
+};
+struct rvm_guest_set_trap_args {
+ uint16_t vmid;
+ enum rvm_trap_kind kind;
+ uint64_t addr;
+ uint64_t size;
+ uint64_t key;
+};
+
+struct rvm_vcpu_create_args {
+ uint16_t vmid;
+ uint64_t entry;
+};
+
+struct rvm_vcpu_resmue_args {
+ uint16_t vcpu_id;
+ struct rvm_exit_packet packet;
+};
+
+struct rvm_vcpu_state_args {
+ uint16_t vcpu_id;
+ enum rvm_vcpu_read_write_kind kind;
+ union {
+ struct rvm_vcpu_state* vcpu_state_ptr;
+ struct rvm_vcpu_io* vcpu_io_ptr;
+ };
+ uint64_t buf_size;
+};
+
+struct rvm_vcpu_interrupt_args {
+ uint16_t vcpu_id;
+ uint32_t vector;
+};
+
+#endif // RVM_H

examples/ko/rvm.c

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+#include <linux/fs.h>
+#include <linux/kernel.h>
+#include <linux/miscdevice.h>
+#include <linux/module.h>
+
+#include <rvm.h>
+
+static int rvm_open(struct inode* inode, struct file* file) {
+ pr_info("[RVM] rvm_open\n");
+ return 0;
+}
+
+static int rvm_release(struct inode* inode, struct file* file) {
+ pr_info("[RVM] rvm_release\n");
+ return 0;
+}
+
+static long rvm_ioctl(struct file* filp, unsigned int ioctl, unsigned long arg) {
+ pr_info("[RVM] rvm_ioctl %x %lx\n", ioctl, arg);
+ return -2;
+}
+
+static const struct file_operations rvm_fops = {
+ .owner = THIS_MODULE,
+ .open = rvm_open,
+ .release = rvm_release,
+ .unlocked_ioctl = rvm_ioctl,
+ .llseek = no_llseek,
+};
+
+struct miscdevice rvm_device = {
+ .minor = 255,
+ .name = "rvm",
+ .fops = &rvm_fops,
+};
+
+static int __init rvm_init(void) {
+ int err = misc_register(&rvm_device);
+ if (err) {
+ pr_err("[RVM] cannot register misc device\n");
+ return err;
+ }
+
+ pr_info("[RVM] module_init\n");
+ return 0;
+}
+
+static void __exit rvm_exit(void) {
+ misc_deregister(&rvm_device);
+ pr_info("[RVM] module_exit\n");
+}
+
+module_init(rvm_init);
+module_exit(rvm_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Yuekai Jia");
+MODULE_DESCRIPTION("Rcore Virtual Machine.");
+MODULE_VERSION("0.1.0");