linux 内核 kvm中的vcpu描述
此结构也是KVM架构层抽象出的虚拟CPU描述，这里跟前面的KVM结构一样，是内核对虚拟机一系列资源抽象后得到的数据描述。
include/linux/kvm_host.h
struct kvm_vcpu {
struct kvm *kvm;所关联的虚拟机描述
#ifdef CONFIG_PREEMPT_NOTIFIERS
struct preempt_notifier preempt_notifier;
#endif
int cpu;
int vcpu_id;虚拟CPU的id
int srcu_idx;
int mode;
unsigned long requests;
unsigned long guest_debug;
int pre_pcpu;
struct list_head blocked_vcpu_list;
struct mutex mutex;
struct kvm_run *run;
int fpu_active;
int guest_fpu_loaded, guest_xcr0_loaded;
unsigned char fpu_counter;
struct swait_queue_head wq;
struct pid *pid;
int sigset_active;
sigset_t sigset;
struct kvm_vcpu_stat stat;
unsigned int halt_poll_ns;
bool valid_wakeup;
#ifdef CONFIG_HAS_IOMEM
int mmio_needed;
int mmio_read_completed;
int mmio_is_write;
int mmio_cur_fragment;
int mmio_nr_fragments;
struct kvm_mmio_fragment mmio_fragments[KVM_MAX_MMIO_FRAGMENTS];
#endif
#ifdef CONFIG_KVM_ASYNC_PF
struct {
u32 queued;
struct list_head queue;
struct list_head done;
spinlock_t lock;
} async_pf;
#endif
#ifdef CONFIG_HAVE_KVM_CPU_RELAX_INTERCEPT
struct {
bool in_spin_loop;
bool dy_eligible;
} spin_loop;
#endif
bool preempted;
struct kvm_vcpu_arch arch;
struct dentry *debugfs_dentry;
};
这里需要关注kvm_run结构，其跟具体支持虚拟化的host cpu密切相关。
