On Fri, 12 Apr 2013 18:24:23 +0200 Igor Mammedov <imamm...@redhat.com> wrote:
> On Fri, 12 Apr 2013 12:35:14 -0300 > Eduardo Habkost <ehabk...@redhat.com> wrote: > > > On Fri, Apr 12, 2013 at 05:16:20PM +0200, Igor Mammedov wrote: > > > On Fri, 12 Apr 2013 10:35:53 -0300 > > > Eduardo Habkost <ehabk...@redhat.com> wrote: > > > > > > > On Fri, Apr 12, 2013 at 12:53:51PM +0200, Igor Mammedov wrote: > > > > > On Thu, 11 Apr 2013 15:59:40 -0300 > > > > > Eduardo Habkost <ehabk...@redhat.com> wrote: > > > > > > > > > > > On Thu, Apr 11, 2013 at 04:51:46PM +0200, Igor Mammedov wrote: > > > > > > > ... so that on reboot BIOS could read current available CPU > > > > > > > count > > > > > > > > > > > > > > Signed-off-by: Igor Mammedov <imamm...@redhat.com> > > > > > > > v2: > > > > > > > * > > > > > > > s/qemu_register_cpu_add_notifier()/qemu_register_cpu_added_notifier()/ > > > > > > > --- hw/timer/mc146818rtc.c | 12 ++++++++++++ > > > > > > > 1 file changed, 12 insertions(+) > > > > > > > > > > > > Initialization of the cmos fields (including 0x5F) is done on > > > > > > pc.c:pc_cmos_init(). What about making the field increment inside > > > > > > pc.c as well? > > > > > I looked at possibility but discarded it because to increment it > > > > > there initial value should be -1 (field is zero based) which is not > > > > > obvious, plug ugly casting to singed variable. > > > > > Result looked ugly. > > > > > > > > I was thinking about simply adding exactly the same code with exactly > > > > the same logic, but inside pc.c instead of of mc146818rtc.c. Instead > > > > of registering the notifier inside rtc_initfn(), register exactly the > > > > same notifier with exactly the same code, but inside pc_cmos_init() > > > > (that's where 0x5f is initialized). > > > > > > > > It would even be safer and easier review and ensure correctness: with > > > > this patch, the notifier is registered very early, even before > > > > pc_cmos_init() initializes 0x5f to smp_cpus. CPU hotplug events are > > > > unlikely to be emitted before pc_cmos_init() is called, but still: why > > > it isn't be called, hot-add is available only after machine initialized. > > > > > > > make the initialization ordering so subtle if we don't have to? > > > Currently cmos init doesn't look like proper QOM object and has 3 stage > > > initialization: realize(), then pc_cmos_init() the last > > > pc_cmos_init_late(). The last 2 calls are made after realize(), setting > > > various properties. Which looks wrong from QOM perspective, so I'm > > > against of stuffing more internal stuff in arbitrary places. We should > > > do opposite instead. > > > > True, but as we already have this weird 3-stage initialization process > > and we won't fix it really soon, I would really prefer to keep parts of > > the code that are closely related and depend on each other in the same > > part of the code. > > > > > > > > If you look at mc146818rtc.c or hw/acpi/piix4.c, all notifiers are > > > private to object and registered at realize() time. It looks like > > > initialization order of mc146818rtc should be fixed, instead of > > > adapting new code to it. > > > > > > So since this patch doesn't break or violate anything in current code, > > > I'd like to leave it as it is. > > > > If you insist into making the mc146818rtc device take care of > > maintaining the 0x5f value by itself, why not doing: > > > > s->cmos_data[0x5f] = smp_cpus - 1; > > > > inside rtc_initfn() instead of pc_cmos_init() as well? > Device is used not only by target-i386. > Right way would be to redesign rtc_init() and rtc_initfn() and it would be > quite an intrusive patch. > > That said it looks like current patch is incorrect if other targets > are considered, where s->cmos_data[0x5f] doesn't mean smp_cpus - 1. That > looks like a good reason to place notifier into pc.c and make it board > specific. I'll redo it for the next respin. > On the other hand, it probably would be better to make it a method and override it in pc.c
