Hi Pierrick,
May 13, 2025 at 12:45 AM, Pierrick Bouvier wrote:
> On 5/11/25 6:13 AM, Julian Ganz wrote:
>
> >
> > We recently introduced new plugin API for registration of discontinuity
> > related callbacks. This change introduces a minimal plugin showcasing
> > the new API. It simply counts the occurances of interrupts, exceptions
> > and host calls per CPU and reports the counts when exitting.
> > Signed-off-by: Julian Ganz <neither@nut.email>
> > ---
> > contrib/plugins/meson.build | 3 +-
> > contrib/plugins/traps.c | 100 ++++++++++++++++++++++++++++++++++++
> > docs/about/emulation.rst | 8 +++
> > 3 files changed, 110 insertions(+), 1 deletion(-)
> > create mode 100644 contrib/plugins/traps.c
> > +typedef struct {
> > + uint64_t interrupts;
> > + uint64_t exceptions;
> > + uint64_t hostcalls;
> > + bool active;
> >
> The scoreboard is automatically resized only when a new vcpu is initialized,
> so if an entry is present, it means it's present by definition.
> Thus, you can remove the active field.
In plugin_exit we iterate over all VCPUs and retrieve the corresponding
entry via qemu_plugin_scoreboard_find, which will initialize a new
entry if one didn't exist at that point. We used the active field to
distinguish between entries we created and those created while printing
the results.
Using qemu_plugin_num_vcpus instead of storing max_vcpus will
(probably) solve this issue. I'll check to make sure and then remove
this field.
> > +} TrapCounters;
> > +
> > +static struct qemu_plugin_scoreboard *traps;
> > +static size_t max_vcpus;
> > +
> >
> You can use qemu_plugin_num_vcpus() instead of keeping a copy of max_vcpus.
> It returns the number of vcpus started, which guarantees you'll find
> associated entries in any scoreboard.
Thanks, I must have missed that function.
Regards,
Julian
