二、下半部分 5、在调用ioctl时 SYSCALL_DEFINE3(ioctl, unsigned int, fd, unsigned int, cmd, unsigned long, arg) ->vfs_ioctl，会用到vfs_ioctl.unlocked_ioctl也就是kvm_vm_ioctl kvm_vm_ioctl->kvm_vm_ioctl_create_vcpu ->kvm_arch_vcpu_precreate ->kvm_vcpu_init ->kvm_arch_vcpu_create ->kvm_get_kvm ->create_vcpu_fd，生成设备文件inode ->kvm_arch_vcpu_postcreate 其中，kvm_arch_vcpu_create ->kvm_mmu_create ->vcpu->arch.user_fpu = kmem_cache_zalloc(x86_fpu_cache, GFP_KERNEL_ACCOUNT); ->kvm_pmu_init(vcpu); ->kvm_hv_vcpu_init(vcpu); ->kvm_x86_ops.vcpu_create(vcpu); ->kvm_vcpu_mtrr_init(vcpu); ->vcpu_load(vcpu); ->kvm_vcpu_reset(vcpu, false); ->kvm_init_mmu(vcpu, false); //包括init_kvm_tdp_mmu和init_kvm_softmmu两种虚拟化方式 6、启动虚拟机，还是文件操作 static struct file_operations kvm_vcpu_fops = { .release = kvm_vcpu_release, .unlocked_ioctl = kvm_vcpu_ioctl, .mmap = kvm_vcpu_mmap, .llseek = noop_llseek, KVM_COMPAT(kvm_vcpu_compat_ioctl), }; 7、在调用ioctl时KVM_RUN SYSCALL_DEFINE3(ioctl, unsigned int, fd, unsigned int, cmd, unsigned long, arg) ->vfs_ioctl，会用到vfs_ioctl.unlocked_ioctl也就是kvm_vcpu_ioctl kvm_vcpu_ioctl-> case KVM_RUN: kvm_arch_vcpu_ioctl_run 其中，kvm_arch_vcpu_ioctl_run->vcpu_run->vcpu_enter_guest 8、IO同样有虚拟化和半虚拟化两种，一个处理函数为kvm_fast_pio，另一个为kvm_emulate_instruction

一、上半部分 1、内核模块初始化 module_init(vmx_init)->kvm_init module_init(svm_init)->kvm_init 其中，kvm_init ->kvm_arch_init ->kvm_irqfd_init ->kvm_arch_hardware_setup ->misc_register(&kvm_dev) 2、从数据结构角度，又可以看到了设备皆为文件的思想 static struct miscdevice kvm_dev = { KVM_MINOR, "kvm", &kvm_chardev_ops, }; static struct file_operations kvm_chardev_ops = { .unlocked_ioctl = kvm_dev_ioctl, .llseek = noop_llseek, KVM_COMPAT(kvm_dev_ioctl), }; 通过misc_register，实现了操作的绑定。 3、通过上面的数据结构，我们就可以找到创建虚拟机的方法，并生成控制文件 kvm_dev.kvm_chardev_ops.kvm_dev_ioctl ioctl系统调用KVM_CREATE_VM，效果也是一样的： SYSCALL_DEFINE3(ioctl, unsigned int, fd, unsigned int, cmd, unsigned long, arg) ->vfs_ioctl，会用到vfs_ioctl.unlocked_ioctl也就是kvm_dev_ioctl ->case KVM_CREATE_VM: -> r = kvm_dev_ioctl_create_vm(arg); ->file = anon_inode_getfile("kvm-vm", &kvm_vm_fops, kvm, O_RDWR); 其中，kvm_dev_ioctl_create_vm ->kvm_create_vm ->->kvm_arch_init_vm ->->hardware_enable_all ->->kvm_arch_post_init_vm ->->list_add(&kvm->vm_list, &vm_list); 4、生成虚拟CPU套路很相似，仍是文件操作 static struct file_operations kvm_vm_fops = { .release = kvm_vm_release, .unlocked_ioctl = kvm_vm_ioctl, .llseek = noop_llseek, KVM_COMPAT(kvm_vm_compat_ioctl), }; 创建虚拟机时，anon_inode_getfile("kvm-vm", &kvm_vm_fops, kvm, O_RDWR)，实际上就把文件和kvm_vm_fops绑定了起来。