Re: [Qemu-devel] [PATCH v6 3/7] s390x/cpu: Move some CPU initialization into realize

[Matthew Rosato]

On 02/22/2016 12:35 PM, Andreas Färber wrote:
> Am 22.02.2016 um 18:06 schrieb Matthew Rosato:
>> In preparation for hotplug, defer some CPU initialization
>> until the device is actually being realized.
>>
>> Signed-off-by: Matthew Rosato 
>> ---
>>  target-s390x/cpu.c | 9 ++---
>>  1 file changed, 6 insertions(+), 3 deletions(-)
> 
> Looks reasonable on a brief sight,
> 
> Reviewed-by: Andreas Färber 
> 
> What is env->cpu_num used for? In particular, have you thought about
> linux-user creating multiple CPUs and possibly destroying them again?
> 

env->cpu_num is intended to map to the s390x architecture concept of a
cpu address, which is a numeric ID used to differentiate between CPUs
when a targeted event occurs (like an unsolicited interrupt that must be
handled on behalf of a particular CPU).  s390x architecture currently
cannot tolerate CPU destruction.

Matt

Re: [Qemu-devel] [PATCH v6 3/7] s390x/cpu: Move some CPU initialization into realize

[Andreas Färber]

Am 22.02.2016 um 18:06 schrieb Matthew Rosato:
> In preparation for hotplug, defer some CPU initialization
> until the device is actually being realized.
> 
> Signed-off-by: Matthew Rosato 
> ---
>  target-s390x/cpu.c | 9 ++---
>  1 file changed, 6 insertions(+), 3 deletions(-)

Looks reasonable on a brief sight,

Reviewed-by: Andreas Färber 

What is env->cpu_num used for? In particular, have you thought about
linux-user creating multiple CPUs and possibly destroying them again?

Regards,
Andreas

-- 
SUSE Linux GmbH, Maxfeldstr. 5, 90409 Nürnberg, Germany
GF: Felix Imendörffer, Jane Smithard, Graham Norton; HRB 21284 (AG Nürnberg)

[Qemu-devel] [PATCH v6 3/7] s390x/cpu: Move some CPU initialization into realize

[Matthew Rosato]

In preparation for hotplug, defer some CPU initialization
until the device is actually being realized.

Signed-off-by: Matthew Rosato 
---
 target-s390x/cpu.c | 9 ++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/target-s390x/cpu.c b/target-s390x/cpu.c
index 603c2a1..8dfd063 100644
--- a/target-s390x/cpu.c
+++ b/target-s390x/cpu.c
@@ -195,7 +195,13 @@ static void s390_cpu_realizefn(DeviceState *dev, Error 
**errp)
 {
 CPUState *cs = CPU(dev);
 S390CPUClass *scc = S390_CPU_GET_CLASS(dev);
+S390CPU *cpu = S390_CPU(dev);
+CPUS390XState *env = >env;
 
+#if !defined(CONFIG_USER_ONLY)
+qemu_register_reset(s390_cpu_machine_reset_cb, cpu);
+#endif
+env->cpu_num = cs->cpu_index;
 s390_cpu_gdb_init(cs);
 qemu_init_vcpu(cs);
 #if !defined(CONFIG_USER_ONLY)
@@ -213,7 +219,6 @@ static void s390_cpu_initfn(Object *obj)
 S390CPU *cpu = S390_CPU(obj);
 CPUS390XState *env = >env;
 static bool inited;
-static int cpu_num = 0;
 #if !defined(CONFIG_USER_ONLY)
 struct tm tm;
 #endif
@@ -223,7 +228,6 @@ static void s390_cpu_initfn(Object *obj)
 cs->exception_index = EXCP_HLT;
 cpu_exec_init(cs, _abort);
 #if !defined(CONFIG_USER_ONLY)
-qemu_register_reset(s390_cpu_machine_reset_cb, cpu);
 qemu_get_timedate(, 0);
 env->tod_offset = TOD_UNIX_EPOCH +
   (time2tod(mktimegm()) * 10ULL);
@@ -232,7 +236,6 @@ static void s390_cpu_initfn(Object *obj)
 env->cpu_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, s390x_cpu_timer, cpu);
 s390_cpu_set_state(CPU_STATE_STOPPED, cpu);
 #endif
-env->cpu_num = cpu_num++;
 
 if (tcg_enabled() && !inited) {
 inited = true;
-- 
1.9.1