Re: Fwd: Xen-4.1.6.1 backport for XSA156

[Stefan Bader <stefan.bader@canonical.com>]

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On 20.11.2015 17:54, Jan Beulich wrote:
>>>> On 20.11.15 at 17:15, <stefan.bader@canonical.com> wrote:
>> So this is a quick hack I just tried and that keeps the HVM alive:
>>
>> @@ -1294,7 +1288,6 @@ void vmx_inject_hw_exception(int trap, i
>>      switch ( trap )
>>      {
>>      case TRAP_debug:
>> -        type = X86_EVENTTYPE_SW_EXCEPTION;
>>          if ( guest_cpu_user_regs()->eflags & X86_EFLAGS_TF )
>>          {
>>              __restore_debug_registers(curr);
>> @@ -1302,6 +1295,13 @@ void vmx_inject_hw_exception(int trap, i
>>          }
>>          if ( cpu_has_monitor_trap_flag )
>>              break;
>> +        if ( curr->domain->debugger_attached )
>> +        {
>> +            /* Debug/Int3: Trap to debugger. */
>> +            domain_pause_for_debugger();
>> +            return;
>> +        }
>> +        break;
>>      case TRAP_int3:
>>          if ( curr->domain->debugger_attached )
>>          {
>>
>> Though this looks like an ugly hack and probably is wrong in the other case of
>> TRAP_debug caused by an opcode...
> 
> Right, and I'm afraid this case doesn't get handled correctly even on
> -unstable now. But apart from that aspect I think the change above
> is okay.

Oh, ok. Thanks for the review. I guess then I go with that. At least this does
no longer crash.

-Stefan

> 
> Jan
> 



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