Re: [Qemu-devel] [PATCH v4 2/2] intel-iommu: start to use error_report_once

[Markus Armbruster]

Auger Eric <address@hidden> writes:

> Hi,
> On 06/13/2018 10:05 AM, Markus Armbruster wrote:
>> Peter Xu <address@hidden> writes:
>> 
>>> Replace existing trace_vtd_err() with error_report_once() then stderr
>>> will capture something if any of the error happens, meanwhile we don't
>>> suffer from any DDOS.  Then remove the trace point.  Since at it,
>>> provide more information where proper (now we can pass parameters into
>>> the report function).
>>>
>>> Reviewed-by: Philippe Mathieu-Daudé <address@hidden>
>>> Signed-off-by: Peter Xu <address@hidden>
>>> ---
>>>  hw/i386/intel_iommu.c | 59 ++++++++++++++++++++++++-------------------
>>>  hw/i386/trace-events  |  1 -
>>>  2 files changed, 33 insertions(+), 27 deletions(-)
>> 
>> Michael, would you give your Reviewed-by or Acked-by?  I'd take the
>> series through my tree then.
>> 
>> [...]
>> 
> Sorry to enter this thread at this late stage. Just one question: on the
> smmuv3 emulation code, Peter (Maydell) urged me to use
> qemu_log_mask(LOG_GUEST_ERROR, ...) whenever the error was triggered by
> a guest bad behavior. So what is the final guidance to avoid the DOS you
> mention?

Does the user need to know about the error condition?

If yes, we should tell him.  Logging is not telling.

Peter, what do you think?