On Tue, Mar 27, 2018 at 10:08:20AM +0800, Zhe Liu wrote:
> Dear Kevin,
> Thanks for getting back to me. Your replay helps me a lot. And there
> are two things I want to make clear.
> 1. > The real-mode handlers installed at 0x60-0x66 are intended for
> software interrupts.
> During the booting of the vm seabios, which modules will raise the software
> interrupts? (Qemu? KVM? VirtualMachine?)
Software interrupts are for guest software to raise and interally
catch. Some old DOS-era software does this.
> 2. In src/post.c: init_ivt, the handlers for 0x60-0x66 is set to none
> as below.
> for (i=0x60; i<=0x66; i++)
> SET_IVT(i, SEGOFF(0, 0));
> If I change the handlers of 0x60-0x66 to default handler, which is
> "iret" directly, is there some side effects?
It might break some old DOS-era software.
Notably, though, if something external is raising random interrupts,
it's likely going to cause havoc with both modern and old software.