Re: [PATCH v3 6/7] tests/qtest: Add API functions to capture IRQ toggling

[Philippe Mathieu-Daudé]

On 7/1/25 19:35, Philippe Mathieu-Daudé wrote:
> Cc'ing maintainers:
>
> $ ./scripts/get_maintainer.pl -f tests/qtest/libqtest.c
> Fabiano Rosas <farosas@suse.de> (maintainer:qtest)
> Laurent Vivier <lvivier@redhat.com> (maintainer:qtest)
> Paolo Bonzini <pbonzini@redhat.com> (reviewer:qtest)
>
> On 16/12/24 15:18, Gustavo Romero wrote:
> > Currently, the QTest API does not provide a function to capture when an
> > IRQ line is raised or lowered, although the QTest Protocol already
> > reports such IRQ transitions. As a consequence, it is also not possible
> > to capture when an IRQ line is toggled. Functions like qtest_get_irq()
> > only read the current state of the intercepted IRQ lines, which is
> > already high (or low) when the function is called if the IRQ line is
> > toggled. Therefore, these functions miss the IRQ line state transitions.
> >
> > This commit introduces two new API functions:
> > qtest_get_irq_raised_counter() and qtest_get_irq_lowered_counter().
> > These functions allow capturing the number of times an observed IRQ line
> > transitioned from low to high state or from high to low state,
> > respectively.
> >
> > When used together, these new API functions then allow checking if one
> > or more pulses were generated (indicating if the IRQ line was toggled).
> >
> > Signed-off-by: Gustavo Romero <gustavo.romero@linaro.org>
> > Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
> > Acked-by: Thomas Huth <thuth@redhat.com>
> > ---
> >   tests/qtest/libqtest.c | 24 ++++++++++++++++++++++++
> >   tests/qtest/libqtest.h | 28 ++++++++++++++++++++++++++++
> >   2 files changed, 52 insertions(+)


> > +uint64_t qtest_get_irq_raised_counter(QTestState *s, int num)
> > +{
> > +    /* dummy operation in order to make sure irq is up to date */
> > +    qtest_inb(s, 0);
>
> Isn't it better to simply call:
>
>         qtest_rsp(s);
>
> ?

Sorry I misunderstood. You want to flush the qtest socket, right?
Could this be sufficient?

          s->ops.send(s, "\n");

Otherwise I'd rather add a "nop" command. Seeing "inb" in traces
is very confusing.

> > +
> > +    return s->irq_raised_counter[num];
> > +}