IO指令模拟流程（11）

于是，在进入hvm_io_assist后，将io_state置为HVMIO_completed，并二次进入handle_mmio。

    if ( (io_state == HVMIO_awaiting_completion) ||

         (io_state ==HVMIO_handle_mmio_awaiting_completion) )

    {

        curr->arch.hvm_vcpu.io_state =HVMIO_completed;

        curr->arch.hvm_vcpu.io_data = p->data;

        if ( io_state == HVMIO_handle_mmio_awaiting_completion )

            (void)handle_mmio();

    }
 

 

于是二次进入hvmemul_do_io，将io_state置为HVMIO_none。读指令返回X86EMUL_OKAY，模拟成功。

    switch ( curr->arch.hvm_vcpu.io_state )

    {

    case HVMIO_none:

        break;

    case HVMIO_completed:

        curr->arch.hvm_vcpu.io_state =HVMIO_none;

        if ( p_data == NULL )

            return X86EMUL_UNHANDLEABLE;

        goto finish_access;