Daniel P. Berrangé <berra...@redhat.com> writes:
> On Fri, Jul 18, 2025 at 07:59:50AM +0200, Markus Armbruster wrote:
>> Markus Armbruster <arm...@redhat.com> writes:
>>
>> > Adam Williamson <awill...@redhat.com> writes:
>> >
>> >> In cfcacba an `error_report` was added to this file, but the
>> >> corresponding include of `qemu/error-report.h` was missed. This
>> >> only becomes apparent when building against Xen 4.20+.
>> >>
>> >> Signed-off-by: Adam Williamson <awill...@redhat.com>
>> >> ---
>> >> hw/xen/xen_pt.c | 1 +
>> >> 1 file changed, 1 insertion(+)
>> >>
>> >> diff --git a/hw/xen/xen_pt.c b/hw/xen/xen_pt.c
>> >> index 9d16644d82..006b5b55f2 100644
>> >> --- a/hw/xen/xen_pt.c
>> >> +++ b/hw/xen/xen_pt.c
>> >> @@ -54,6 +54,7 @@
>> >>
>> >> #include "qemu/osdep.h"
>> >> #include "qapi/error.h"
>> >> +#include "qemu/error-report.h"
>> >> #include <sys/ioctl.h>
>> >>
>> >> #include "hw/pci/pci.h"
>> >
>> > Uh, error-report.h is included without this for me. To see, build with
>> > -H:
>> >
>> > . /work/armbru/qemu/hw/xen/xen_pt.h
>> > .. /work/armbru/qemu/include/hw/xen/xen_native.h
>> > ... /work/armbru/qemu/hw/xen/trace.h
>> > .... ./trace/trace-hw_xen.h
>> > ..... /work/armbru/qemu/include/qemu/error-report.h
>>
>> Just remembered: the generated trace header includes error-report.h only
>> when trace's log backend is enabled.
>
> Hmm, that's rather an unfortunate trap-door :-( Given that 'log' is enabled
> by default when building from git we'll never see missing error-report.h
> problems in daily work.
Correct.
> Looking at the log backend it appears that originally it would
> unconditionally include the timestamp when calling qemu_log, but
> then changed that to opt-in with
>
> commit 418ed14268f797a5142b60cd557cd598eb548c66
> Author: Stefan Hajnoczi <stefa...@redhat.com>
> Date: Mon Jan 25 11:35:07 2021 +0000
>
> trace: make the 'log' backend timestamp configurable
>
> requiring -msg timestamp=on, which was a pre-existing flag that already
> did a similar toggle for the 'error_report' function. The goal makes
> sense, but it introduced the error-report.h trap door
>
> When I see that I also question why the 'log' backend should be a
> special case user of qemu_log() ? Why shouldn't we emit timestamps
> for all usage of qemu_log() ?
>
> If we changed the qemu_log impl to honour the timestamp toggle, then
> all users of qemu_log benefit. We then eliminate error-report.h usage
> in trace.h headers, and also cut the code size for trace points
> significantly
>
>
> static inline void _nocheck__trace_object_dynamic_cast_assert(const char *
> type, const char * target, const char * file, int line, const char * func)
> {
> if (trace_event_get_state(TRACE_OBJECT_DYNAMIC_CAST_ASSERT) &&
> qemu_loglevel_mask(LOG_TRACE)) {
> if (message_with_timestamp) {
> struct timeval _now;
> gettimeofday(&_now, NULL);
> qemu_log("%d@%zu.%06zu:object_dynamic_cast_assert " "%s->%s
> (%s:%d:%s)" "\n",
> qemu_get_thread_id(),
> (size_t)_now.tv_sec, (size_t)_now.tv_usec
> , type, target, file, line, func);
> } else {
> qemu_log("object_dynamic_cast_assert " "%s->%s (%s:%d:%s)" "\n",
> type, target, file, line, func);
> }
> }
> }
>
> down to
>
>
> static inline void _nocheck__trace_object_dynamic_cast_assert(const char *
> type, const char * target, const char * file, int line, const char * func)
> {
> if (trace_event_get_state(TRACE_OBJECT_DYNAMIC_CAST_ASSERT) &&
> qemu_loglevel_mask(LOG_TRACE)) {
> qemu_log("object_dynamic_cast_assert " "%s->%s (%s:%d:%s)" "\n",
> type, target, file, line, func);
> }
> }
>
> which feels more in keeping with the kind of level of complexity you should
> want to be inlined in trace callers.
Oh yes. We should do this even if we find a reason for keeping
qemu_log() as it is. The obvious way would be a new function
qemu_log_with_timestamp().
