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Re: [Qemu-devel] [PATCH 8/8] qom: Make CPU a child of DeviceState
From: |
Igor Mammedov |
Subject: |
Re: [Qemu-devel] [PATCH 8/8] qom: Make CPU a child of DeviceState |
Date: |
Wed, 2 Jan 2013 17:40:58 +0100 |
On Wed, 02 Jan 2013 16:08:42 +0100
Andreas Färber <address@hidden> wrote:
> Am 05.12.2012 17:49, schrieb Eduardo Habkost:
> > This finally makes the CPU class a child of DeviceState, allowing us to
> > start using DeviceState properties on CPU subclasses.
>
> To avoid confusion with child<> properties and DeviceState vs.
> DeviceClass I have reworded this to "subclass of Device" in my
> qom-cpu-dev queue.
>
> >
> > It has no_user=1, as creating CPUs using -device doesn't work yet.
> >
>
> > (based on a previous patch from Igor Mammedov)
>
> Can this comment be turned into or amended by the usual Signed-off-by?
Signed-off-by should be ok.
>
> >
> > Signed-off-by: Eduardo Habkost <address@hidden>
> > ---
> > Changes v1 (imammedo) -> v2 (ehabkost):
> > - Change CPU type declaration to hae TYPE_DEVICE as parent
> >
> > Changes v2 -> v3 (ehabkost):
> > - Set no_user=1 on the CPU class
> > ---
> > include/qemu/cpu.h | 6 +++---
> > qom/cpu.c | 5 ++++-
> > 2 files changed, 7 insertions(+), 4 deletions(-)
> >
> > diff --git a/include/qemu/cpu.h b/include/qemu/cpu.h
> > index 61b7698..bc004fd 100644
> > --- a/include/qemu/cpu.h
> > +++ b/include/qemu/cpu.h
> > @@ -20,7 +20,7 @@
> > #ifndef QEMU_CPU_H
> > #define QEMU_CPU_H
> >
> > -#include "qemu/object.h"
> > +#include "hw/qdev-core.h"
> > #include "qemu-thread.h"
> >
> > /**
> [...]
> > diff --git a/qom/cpu.c b/qom/cpu.c
> > index 5b36046..d301f72 100644
> > --- a/qom/cpu.c
> > +++ b/qom/cpu.c
> > @@ -20,6 +20,7 @@
> >
> > #include "qemu/cpu.h"
> > #include "qemu-common.h"
> > +#include "hw/qdev-core.h"
>
> Already included via qom/cpu.h (formerly qemu/cpu.h) above, dropping.
>
> >
> > void cpu_reset(CPUState *cpu)
> > {
> > @@ -36,14 +37,16 @@ static void cpu_common_reset(CPUState *cpu)
> >
> > static void cpu_class_init(ObjectClass *klass, void *data)
> > {
> > + DeviceClass *dc = DEVICE_CLASS(klass);
> > CPUClass *k = CPU_CLASS(klass);
> >
> > k->reset = cpu_common_reset;
> > + dc->no_user = 1;
> > }
>
> I wonder if we should add a comment that we are intentionally not
> hooking up dc->reset (yet)?
not relevant to this patch, could be separate patch though.
>
> >
> > static TypeInfo cpu_type_info = {
>
> Would like to add the missing const while touching this.
>
> > .name = TYPE_CPU,
> > - .parent = TYPE_OBJECT,
> > + .parent = TYPE_DEVICE,
> > .instance_size = sizeof(CPUState),
> > .abstract = true,
> > .class_size = sizeof(CPUClass),
>
> My testing so far confirms that the combination of object_new() without
> qdev_init[_nofail]() is working fine.
+1, I tested this combo for (x86)-(softmmu|linux-user) targets, no issues were
found so far.
>
> Using qdev_create() in the current state of stubs would lead to a silly
> if-bus-is-NULL-set-it-to-NULL sequence on top of object_new(). I do not
> expect qdev_create() to grow in functionality, so continuing to use
> object_new() should be okay - SoCs like my Tegra model may want to use
> object_initialize() so we cannot prescribe using qdev_create() anyway.
>
> qdev_init_nofail() would call the qdev initfn (to be replaced by
> realizefn, not used for CPU in this patch), then if no parent add it to
> /machine/unassigned, register VMSD if not NULL, update the internal
> state (blocking static property changes) and if hotplugged reset (unused
> due to dc->no_user and lack of dc->reset). The /machine/unassigned part
> may be interesting, e.g., for APIC modelling (so that we can model the
> former ptr property / now pointer-setting as a link<> property).
>
> With these considerations I am leaning towards accepting this patch if
> nobody objects, so that we can move on to the next refactorings...
+1
>
> Regards,
> Andreas
>