On Thu, 31 Aug 2017 15:44:38 +0200
David Hildenbrand <david@redhat.com> wrote:
> On 31.08.2017 15:19, Igor Mammedov wrote:
> > cpu_s390x_init() is used only *-user targets indirectly
> > via cpu_init() macro and has a hack to assign ids to created
> > cpus (I'm not sure if 'id' really matters to *-user emulation).
>
> It only has one cpu, right? With the below mentioned patch, the default
> "id"/ (the cpu_addr) will be 0. So you can create one CPU without any
> hacks. Or can it create more than 1?
As I understand it creates only one cpu,
but then there is fork related cpu_copy() which creates a cpu
and the rewrites new CPUArchState with old cpu data
CPUState *new_cpu = cpu_init(cpu_model);
CPUArchState *new_env = new_cpu->env_ptr;
...
memcpy(new_env, env, sizeof(CPUArchState));
so I couldn't decide if id is of importance for *-user target
(well, I'm not really interested in *-user), and opted for
keeping current behavior (i.e. not breaking) in this patch
just without cpu_s390x_init().
So if 'id' isn't really needed for *-user target, hunk 2 could be
dropped but it ought to be another patch on top as this change isn't
related to the topic of this patch/series.
> > So to on safe side, instead of having custom wrapper to do numbering
> > replace it with cpu_generic_init() and use S390CPUClass::next_cpu_id
> > which could serve the same purpose as static variable and move cpu->id
> > initialization to s390_cpu_initfn for CONFIG_USER_ONLY use-case.
> >
> > PS:
> > ifdef is ugly but it allows us to hide s390x detail that isn't
> > set by *-user targets and reuse generic cpu creation utility
> > for btoh machine and user emulation.
> >
> > Signed-off-by: Igor Mammedov <imammedo@redhat.com>
> > Acked-by: Cornelia Huck <cohuck@redhat.com>
> > ---
> > v2:
> > - fix merge conflict in target/s390x/cpu.h caused by moving
> > cpu_init/cpu_s390x_init with the file in commit
> > (c862bddbc target/s390x: cleanup cpu.h)
> >
> > CC: Cornelia Huck <cohuck@redhat.com>
> > CC: david@redhat.com
> > CC: Eduardo Habkost <ehabkost@redhat.com>
> >
> > perhaps cpu->id isn't need by CONFIG_USER_ONLY but I'd leave to it
> > s390x maintainers to deal with it.
>
> Will most probably be dropped in
>
> https://lists.gnu.org/archive/html/qemu-devel/2017-08/msg06158.html
>
> > ---
> > target/s390x/cpu.h | 3 +--
> > target/s390x/cpu.c | 7 +++++++
> > target/s390x/helper.c | 14 --------------
> > 3 files changed, 8 insertions(+), 16 deletions(-)
> >
> > diff --git a/target/s390x/cpu.h b/target/s390x/cpu.h
> > index 4ec3380..0bd97a5 100644
> > --- a/target/s390x/cpu.h
> > +++ b/target/s390x/cpu.h
> > @@ -688,8 +688,7 @@ const char *s390_default_cpu_model_name(void);
> >
> >
> > /* helper.c */
> > -S390CPU *cpu_s390x_init(const char *cpu_model);
> > -#define cpu_init(model) CPU(cpu_s390x_init(model))
> > +#define cpu_init(cpu_model) cpu_generic_init(TYPE_S390_CPU, cpu_model)
> > S390CPU *s390x_new_cpu(const char *cpu_model, int64_t id, Error **errp);
> > /* you can call this signal handler from your SIGBUS and SIGSEGV
> > signal handlers to inform the virtual CPU of exceptions. non zero
> > diff --git a/target/s390x/cpu.c b/target/s390x/cpu.c
> > index 7267b60..74b3e4f 100644
> > --- a/target/s390x/cpu.c
> > +++ b/target/s390x/cpu.c
> > @@ -306,6 +306,13 @@ static void s390_cpu_initfn(Object *obj)
> > inited = true;
> > s390x_translate_init();
> > }
> > +
> > +#if defined(CONFIG_USER_ONLY)
> > + {
> > + S390CPUClass *scc = S390_CPU_GET_CLASS(obj);
> > + cpu->id = scc->next_cpu_id;
> > + }
> > +#endif
> > }
> >
> > static void s390_cpu_finalize(Object *obj)
> > diff --git a/target/s390x/helper.c b/target/s390x/helper.c
> > index 3adb9de..ba29504 100644
> > --- a/target/s390x/helper.c
> > +++ b/target/s390x/helper.c
> > @@ -129,20 +129,6 @@ out:
> > return cpu;
> > }
> >
> > -S390CPU *cpu_s390x_init(const char *cpu_model)
> > -{
> > - Error *err = NULL;
> > - S390CPU *cpu;
> > - /* Use to track CPU ID for linux-user only */
> > - static int64_t next_cpu_id;
> > -
> > - cpu = s390x_new_cpu(cpu_model, next_cpu_id++, &err);
> > - if (err) {
> > - error_report_err(err);
> > - }
> > - return cpu;
> > -}
> > -
> > #ifndef CONFIG_USER_ONLY
> >
> > hwaddr s390_cpu_get_phys_page_debug(CPUState *cs, vaddr vaddr)
> >
>
>