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

[Gleb Natapov <gleb@redhat.com>]

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:
> > On Thu, Apr 07, 2011 at 01:32:50PM -0500, Anthony Liguori wrote:
> >> On 04/07/2011 01:10 PM, Peter Maydell wrote:
> >> >On 6 April 2011 20:34, Anthony Liguori<anthony@codemonkey.ws>  wrote:
> >> >>http://publib.boulder.ibm.com/infocenter/lnxinfo/v3r0m0/index.jsp?topic=/liaai/crashdump/liaaicrashdumpnmiipmi.htm
> >> >>
> >> >>If an OS is totally hosed (spinning with interrupts disabled), and NMI can
> >> >>be used to generate a crash dump.
> >> >>
> >> >>It's a debug feature and modelling it exactly the way we are probably makes
> >> >>sense for other architectures too.  The real semantics are basically force
> >> >>guest crash dump.
> >> >Ah, right. (There isn't really an equivalent to this on ARM since
> >> >we don't have a real NMI equivalent. So any implementation for ARM
> >> >qemu would be board dependent since you could wire a watchdog up to
> >> >any interrupt.)
> >> >
> >> >Should we try to pick a command name that says what it's supposed to
> >> >do rather than how it happens to be implemented on x86 ?
> >>
> >> Yup, I was thinking the same thing after I sent the note above.  If
> >> we call it 'force-crash-dump', we can implement it as an NMI on
> >> target-i386 and potentially as something else on a different target.
> >>
> > NMI does not have to generate crash dump on every guest we support.
> > Actually even for windows guest it does not generate one without
> > tweaking registry. For all I know there is a guest that checks mail when
> > NMI arrives. Lets give meaningful name, like inject-nmi, for nmi
> > injection command.
> 
> 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.

--
			Gleb.