Re: [Qemu-devel] [PATCH 2/2 V7] qemu,qmp: add inject-nmi qmp command

[Anthony Liguori <anthony@codemonkey.ws>]

On 04/08/2011 02:17 PM, Blue Swirl wrote:
> On Fri, Apr 8, 2011 at 9:04 AM, Gleb Natapov<gleb@redhat.com>  wrote:
>> On Thu, Apr 07, 2011 at 04:41:03PM -0500, Anthony Liguori wrote:
>>> On 04/07/2011 02:17 PM, Gleb Natapov wrote:
>>>> On Thu, Apr 07, 2011 at 10:04:00PM +0300, Blue Swirl wrote:
>>>>> On Thu, Apr 7, 2011 at 9:51 PM, Gleb Natapov<gleb@redhat.com>    wrote:
>>>>>
>>>>> I'd prefer something more generic like these:
>>>>> raise /apic@fee00000:l1int
>>>>> lower /i44FX-pcihost/e1000@03.0/pinD
>>>>>
>>>>> The clumsier syntax shouldn't be a problem, since this would be a
>>>>> system developer tool.
>>>>>
>>>>> Some kind of IRQ registration would be needed for this to work without
>>>>> lots of changes.
>>>> True. The ability to trigger any interrupt line is very useful for
>>>> debugging. I often re-implement it during debug.
>>> And it's a good thing to have, but exposing this as the only API to
>>> do something as simple as generating a guest crash dump is not the
>>> friendliest thing in the world to do to users.
>>>
>> Well, this is not intended to be used by regular users directly and
>> management can provide nicer interface for issuing NMI. But really,
>> my point is that NMI actually generates guest core dump in such rare
>> cases (only preconfigured Windows guests) that it doesn't warrant to
>> name command as such. Management is in much better position to implement
>> functionality with such name since it knows what type of guest it runs
>> and can tell agent to configure guest accordingly.
> Does the management need to know about each and every debugging
> oriented interface? For example, "info regs",  "info mem", "info irq"
> and tracepoints?
>
> I think giving IRQs symbolic names could solve some other problems as
> well. Maybe it should be possible to connect IRQs in a configuration
> file and even with command line:
> -device port90,irqid=p90out -device pckbd,irqid=kbdout -device
> and,in=p90out,in=kbdout,out=sreset device system_reset,in=sreset

You really want devices to have properties and for the device properties 
to be discoverable.  For instance:

struct DeviceInfo
{
      .name = "and",
      .properties = {
           DEFINE_IRQ_IN(AndDevice, in[0]),
           DEFINE_IRQ_IN(AndDevice, in[1]),
           DEFINE_IRQ_OUT(AndDevice, out),
      },
};

And then you can do:

-device port90,id=port90 -device pckbd,id=pckbd \
-device and,in[0]=port90.out,in[1]=pckbd.out,id=reset_and \
-device system_reset.in=reset_and

Regards,

Anthony Liguori

> or
>
>   -device and,in=/i44FX-pcihost/PIIX3/i8042/out1,in=/i44FX-pcihost/PIIX3/p90/out1,out=/QEMU/system_reset
>