Re: [PATCH 5/6] target/arm: Share ARM_PSCI_CALL trace event between TCG and HVF

["Daniel P. Berrangé" <berrange@redhat.com>]

On Fri, Jul 04, 2025 at 02:14:35PM +0100, Peter Maydell wrote:
> On Mon, 30 Jun 2025 at 17:53, Pierrick Bouvier
> <pierrick.bouvier@linaro.org> wrote:
> >
> > On 6/30/25 6:09 AM, Philippe Mathieu-Daudé wrote:
> > > It is useful to compare PSCI calls of the same guest running
> > > under TCG or HVF.
> > >
> > > Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
> > > ---
> > >   target/arm/hvf/hvf.c    | 3 ++-
> > >   target/arm/tcg/psci.c   | 3 +++
> > >   target/arm/trace-events | 3 +++
> > >   3 files changed, 8 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/target/arm/hvf/hvf.c b/target/arm/hvf/hvf.c
> > > index 7a99118c8c2..6309c5b872e 100644
> > > --- a/target/arm/hvf/hvf.c
> > > +++ b/target/arm/hvf/hvf.c
> > > @@ -34,6 +34,7 @@
> > >   #include "target/arm/multiprocessing.h"
> > >   #include "target/arm/gtimer.h"
> > >   #include "trace.h"
> > > +#include "../trace.h"
> 
> 
> > Just a nit, using 'target/arm/trace.h' might be more readable than
> > '../trace.h'.
> 
> Mmm. docs/devel/tracing.rst rather discourages this:
> 
> # While it is possible to include a trace.h file from outside a source
> file's own
> # sub-directory, this is discouraged in general. It is strongly preferred that
> # all events be declared directly in the sub-directory that uses them. The only
> # exception is where there are some shared trace events defined in the top level
> # directory trace-events file.
> 
> I don't know if we want to loosen that to permit events
> that are shared between multiple subdirs (cc'ing the
> trace subsystem maintainers for their view).
> 
> git grep 'include.*trace.h' | grep -v '"trace.h"'| grep -v 'trace.h:'|less
> 
> suggests that the only current place where we're including
> a trace.h not in the same directory is linux-user, where
> we opt to use the full linux-user/trace.h path. So probably
> for consistency we should use target/arm/trace.h here.

IMHO using the up-level relative paths is desirable, as it reinforces the
intent that we shouldn't be pulling in trace events from arbitrary different
sub-trees of the codebase, only the current dir & its (near) parents.

With regards,
Daniel
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