Re: debug and breakpoint interrupts handling?

On 6/25/07, Dor Laor <dor.laor@xxxxxxxxxxxx> wrote:
> >I am wondering how KVM handles debug and breakpoint interrupt? Does it
> >process them like normal NMI interrupt, or is there any special
> >processing?
> >
>
> I haven't use it but KVM does support qemu'd gdbstub. Both single step
> and breakpoint are possible. From the source code (vmx.c) it seems like
> handle_exception function handle them as regular exceptions (non nmi).

Are you sure? the kvm_vmx_exit_handlers function pointer arrays has
the index named EXIT_REASON_EXCEPTION_NMI, so it must be handled as
NMI to me.

>
> The breakpoint set path starts from gdbsutb.c-> exec.c:
> cpu_breakpoint_insert -> Qemu-kvm.c: kvm_update_debugger
> Call an ioctl from Kvmctl.c:kvm_guest_debug that runs
> Vmx.c:set_guest_debug
>

Thanks for the pointers, Dor. It really helps digging the code.

Bests,
Jun

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