Am 11.02.2013 15:57, schrieb Stefan Hajnoczi: > On Mon, Feb 11, 2013 at 3:34 PM, Peter Maydell <peter.mayd...@linaro.org> > wrote: >> On 11 February 2013 14:19, Andreas Färber <afaer...@suse.de> wrote: >>> Am 11.02.2013 15:01, schrieb Markus Armbruster: >>>> Kevin Wolf <kw...@redhat.com> writes: >>>> >>>>> Am 11.02.2013 14:27, schrieb Stefan Hajnoczi: >>>>>> I think we need to side-track this patch email to figure out what to >>>>>> use: >>>>>> >>>>>> fprintf(stderr) - some warnings/errors use this >>>>>> error_report() - goes to the monitor, if possible, otherwise stderr >>>>> >>>>> These look wrong to me. >>>> >>>> "Wrong" is a bit strong, in particular since there's ample precedence >>>> for these uses. >> >> Certainly for fprintf() I would say "deprecated" wherever >> we have a better API available. >> >>>>>> qemu_log_*() - goes to the qemu log, seems a little TCG-centric >>>>> >>>>> I would suggest either this or just trace points. (And by the way, it's >>>>> a pity that -d is so TCG-centric, it's been more than once the reason >>>>> why I disabled KVM when debugging a guest... Having at least -d int >>>>> would be so useful.) >>>> >>>> Tracepoints don't really fit when we want to report the guest does >>>> something we don't handle. Users deserve fair warning then, don't they? >>>> >>>> Could qemu_log() & friends be made fit for general use? What's missing? >>> >>> Blue already did some work to make it more usable, and I believe Peter >>> adopted LOG_UNIMPL for ARM devices in place of hw_error() >> >> Yes; in particular where we have classes of error message which the >> user may wish to enable or disable (of which "QEMU doesn't implement >> this" and "the guest just did something that's probably a guest bug" >> are two common ones) qemu_log_mask(LOG_*, ...) is the preferred >> API for devices IMHO. So I think Herve's patch is entirely the >> right thing. > > qemu_log_mask() can replace fprintf() but it needs to default to > stderr and a reasonable default mask. It should be used for > non-monitor command errors and warnings. > > Having said that, I think we should use hw_error() or fprintf() in > this patch until qemu_log_mask() replaces them.
Nack. Like I just pointed out, hw_error() is a fatal abort and not a replacement for logging. I don't mind which of the non-fatal logging methods you choose, but guest-triggerable aborting is a semantic change that we should not choose just because someone doesn't like logging API or defaults. Especially not for 1.4. Regards, Andreas -- SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg, Germany GF: Jeff Hawn, Jennifer Guild, Felix Imendörffer; HRB 16746 AG Nürnberg
