Re: debug and breakpoint interrupts handling?

kvm-devel-bounces@xxxxxxxxxxxxxxxxxxxxx wrote:
> 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. 

This exit reason is either NMI, or software interrupt or exception.

Refer update_exception_bitmap for the setting of VM Exit for which
exception (int n).

In normal situation, I think guest int 1/3 directly get handled in
guest.
vcpu->guest_debug.enabled is used for gdb guest thru host.


Guest DR register is not supported yet. See handle_dr of vmx.c


Eddie

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