了解arm64的kvm_vcpu_run_vhe函数

在arch/arm64/kvm/hyp/vhe/switch.c 中，我们有以下代码在 arm64 上运行 EL2（虚拟化层）中的 CPU：

/* Switch to the guest for VHE systems running in EL2 */
static int __kvm_vcpu_run_vhe(struct kvm_vcpu *vcpu)
{
    struct kvm_cpu_context *host_ctxt;
    struct kvm_cpu_context *guest_ctxt;
    u64 exit_code;

    host_ctxt = &this_cpu_ptr(&kvm_host_data)->host_ctxt;
    host_ctxt->__hyp_running_vcpu = vcpu;
    guest_ctxt = &vcpu->arch.ctxt;

    sysreg_save_host_state_vhe(host_ctxt);

    /*
     * ARM erratum 1165522 requires us to configure both stage 1 and
     * stage 2 translation for the guest context before we clear
     * HCR_EL2.TGE.
     *
     * We have already configured the guest's stage 1 translation in
     * kvm_vcpu_load_sysregs_vhe above.  We must now call
     * __load_guest_stage2 before __activate_traps, because
     * __load_guest_stage2 configures stage 2 translation, and
     * __activate_traps clear HCR_EL2.TGE (among other things).
     */
    __load_guest_stage2(vcpu->arch.hw_mmu);
    __activate_traps(vcpu);

    __kvm_adjust_pc(vcpu);

    sysreg_restore_guest_state_vhe(guest_ctxt);
    __debug_switch_to_guest(vcpu);

    do {
        /* Jump in the fire! */
        exit_code = __guest_enter(vcpu);

        /* And we're baaack! */
    } while (fixup_guest_exit(vcpu, &exit_code));

    sysreg_save_guest_state_vhe(guest_ctxt);

    __deactivate_traps(vcpu);

    sysreg_restore_host_state_vhe(host_ctxt);

    if (vcpu->arch.flags & KVM_ARM64_FP_ENABLED)
        __fpsimd_save_fpexc32(vcpu);

    __debug_switch_to_host(vcpu);

    return exit_code;
}
NOKPROBE_SYMBOL(__kvm_vcpu_run_vhe);

我认为这里重要的一行是__guest_enter，它在这里定义。

我试图了解究竟__kvm_vcpu_run_vhe做了什么。它会阻止呼叫者吗？有什么作用__guest_enter？我查看了代码，它保存并恢复了一些寄存器，但我无法确定它在哪里运行 VM 代码。