Am 07.02.2013 18:46, schrieb Eduardo Habkost:
> On Thu, Feb 07, 2013 at 06:20:52PM +0100, Andreas Färber wrote:
>> Am 07.02.2013 17:40, schrieb Eduardo Habkost:
>>> On Sat, Feb 02, 2013 at 04:04:11PM +0100, Andreas Färber wrote:
>>>> In comparison to DeviceClass::vmsd, CPU VMState is split in two,
>>>> "cpu_common" and "cpu", and uses cpu_index as instance_id instead of -1.
>>>> Therefore add a CPU-specific CPUClass::vmsd field.
>>>>
>>>> Unlike the legacy CPUArchState registration, rather register CPUState.
>>>>
>>>> Signed-off-by: Juan Quintela <quint...@redhat.com>
>>>> Signed-off-by: Andreas Färber <afaer...@suse.de>
>>>> ---
>>>> exec.c | 13 +++++++++++--
>>>> include/qom/cpu.h | 3 +++
>>>> 2 Dateien geändert, 14 Zeilen hinzugefügt(+), 2 Zeilen entfernt(-)
>>>>
>>>> diff --git a/exec.c b/exec.c
>>>> index b85508b..5eee174 100644
>>>> --- a/exec.c
>>>> +++ b/exec.c
>>>> @@ -219,7 +219,7 @@ void cpu_exec_init_all(void)
>>>> #endif
>>>> }
>>>>
>>>> -#if defined(CPU_SAVE_VERSION) && !defined(CONFIG_USER_ONLY)
>>>> +#if !defined(CONFIG_USER_ONLY)
>>>>
>>>> static int cpu_common_post_load(void *opaque, int version_id)
>>>> {
>>>> @@ -266,6 +266,9 @@ CPUState *qemu_get_cpu(int index)
>>>> void cpu_exec_init(CPUArchState *env)
>>>> {
>>>> CPUState *cpu = ENV_GET_CPU(env);
>>>> +#if !defined(CONFIG_USER_ONLY) && !defined(CPU_SAVE_VERSION)
>>>> + CPUClass *cc = CPU_GET_CLASS(cpu);
>>>> +#endif
>>>> CPUArchState **penv;
>>>> int cpu_index;
>>>>
>>>> @@ -290,10 +293,16 @@ void cpu_exec_init(CPUArchState *env)
>>>> #if defined(CONFIG_USER_ONLY)
>>>> cpu_list_unlock();
>>>> #endif
>>>> -#if defined(CPU_SAVE_VERSION) && !defined(CONFIG_USER_ONLY)
>>>> +#if !defined(CONFIG_USER_ONLY)
>>>> vmstate_register(NULL, cpu_index, &vmstate_cpu_common, env);
>>>> +#if defined(CPU_SAVE_VERSION)
>>>> register_savevm(NULL, "cpu", cpu_index, CPU_SAVE_VERSION,
>>>> cpu_save, cpu_load, env);
>>>
>>> What about introducing stub register_savevm() function in libqemustub.a,
>>> so we can eliminate the CONFIG_USER_ONLY ifdefs?
>>>
>>> (we already have vmstate_register()/vmstate_unregister() stubs).
>>
>> register_savevm() itself is not the issue, it's the VMStateDescription
>> itself with all its external references that would be quite some (IMO
>> useless) work to make available to *-user...
>
> Are you talking about the VMStateDescription struct declaration, or
> about actually setting the vmsd field?
I'm talking about, e.g., #include "machine.c", i.e. VMStateDescription
vmstate_something = { ... }; something_else = &vmstate_something;.
This broke horribly.
> The struct declaration is available even if CONFIG_USER_ONLY is set. See
> qdev.c. It doesn't have any #ifdefs around
> vmstate_register()/vmstate_unregister() calls.
>
> I don't suggest we set the field to non-NULL if CONFIG_USER_ONLY is set
> (that would be difficult and unnecessary).
That's what I was saying, yes.
>>>> +#else
>>>
>>> Do we have any architecture that sets CPU_SAVE_VERSION _and_ sets
>>> cc->vmsd at the same time? If not, we could put the "if (cc->vmsd)
>>> vmstate_register()" part outside any #ifdef/#else block.
>>
>> They shouldn't. When this series and any follow-up by Juan himself were
>> applied, there would be no more CPU_SAVE_VERSION and all CPUs would
>> register a vmsd one way or another. Targets to be converted include ppc,
>> arm and sparc.
>>
>> Together with the final RFC patch in this series, doing it inside an
>> #else block avoids repeating the lax checks that have led alpha,
>> openrisc and a few others to not register things correctly.
>
> What exactly were the lax checks that have led them to not register
> things correctly?
In short: Lack of patch 6.
!defined(CPU_SAVE_VERSION) but implementing cpu_save/load when they
should've #define'd CPU_SAVE_VERSION.
In turn I want to assure that when !defined(CPU_SAVE_VERSION)
implementing cpu_save/load leads to build error.
> Would my suggestion below cause the same problems?
>
>> This is the
>> part of the patch that I adopted from Juan. I don't insist though.
>
> I am OK with "#ifdef CPU_SAVE_VERSION" #ifdef because it is for legacy
> code (and should be temporary, right?), but I think we can easily drop
> the #ifdefs around all the other lines. I mean, we can easily make the
> code look like this:
>
> void cpu_exec_init(CPUArchState *env)
> {
> CPUState *cpu = ENV_GET_CPU(env);
> CPUClass *cc = CPU_GET_CLASS(cpu);
> [...]
>
> vmstate_register(NULL, cpu_index, &vmstate_cpu_common, env);
&vmstate_cpu_common will break for linux-user.
> #if defined(CPU_SAVE_VERSION)
> register_savevm(NULL, "cpu", cpu_index, CPU_SAVE_VERSION,
> cpu_save, cpu_load, env);
> #endif
> if (cc->vmsd) {
> vmstate_register(NULL, cpu_index, cc->vmsd, cpu);
> }
> }
>
> If we want to catch architectures that don't set CPU_SAVE_VERSION but
> also don't register any vmsd (is this the bug you are trying to catch?),
> we could do this:
>
> #if defined(CPU_SAVE_VERSION)
> register_savevm(NULL, "cpu", cpu_index, CPU_SAVE_VERSION,
> cpu_save, cpu_load, env);
> #elif !defined(CONFIG_USER_ONLY)
> assert(cc->vmsd);
We would need to leave out the #elif and assert cc->vmsd == NULL, but
then it would address my concern, yes.
!defined(CPU_SAVE_VERSION) => cc->vmsd != NULL is not guaranteed:
For 1.4 some unmigratable CPUs register via dc->vmsd instead.
Regards,
Andreas
> #endif
> if (cc->vmsd) {
> vmstate_register(NULL, cpu_index, cc->vmsd, cpu);
> }
>
>
>>
>> Regards,
>> Andreas
>>
>>>> + if (cc->vmsd != NULL) {
>>>> + vmstate_register(NULL, cpu_index, cc->vmsd, cpu);
>>>> + }
>>>> +#endif
>>>> #endif
>>>> }
>>>>
>>>> diff --git a/include/qom/cpu.h b/include/qom/cpu.h
>>>> index 46f2247..b870752 100644
>>>> --- a/include/qom/cpu.h
>>>> +++ b/include/qom/cpu.h
>>>> @@ -43,6 +43,7 @@ typedef struct CPUState CPUState;
>>>> * @class_by_name: Callback to map -cpu command line model name to an
>>>> * instantiatable CPU type.
>>>> * @reset: Callback to reset the #CPUState to its initial state.
>>>> + * @vmsd: State description for migration.
>>>> *
>>>> * Represents a CPU family or model.
>>>> */
>>>> @@ -54,6 +55,8 @@ typedef struct CPUClass {
>>>> ObjectClass *(*class_by_name)(const char *cpu_model);
>>>>
>>>> void (*reset)(CPUState *cpu);
>>>> +
>>>> + const struct VMStateDescription *vmsd;
>>>> } CPUClass;
>>>>
>>>> struct KVMState;
>>>> --
>>>> 1.7.10.4
>>
>> --
>> SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg, Germany
>> GF: Jeff Hawn, Jennifer Guild, Felix Imendörffer; HRB 16746 AG Nürnberg
--
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg, Germany
GF: Jeff Hawn, Jennifer Guild, Felix Imendörffer; HRB 16746 AG Nürnberg
