Re: [PATCH 2/4] s390x: Cleanup cpu resets

[Janosch Frank <frankja@linux.ibm.com>]

[-- Attachment #1.1: Type: text/plain, Size: 6276 bytes --]

On 11/22/19 11:35 AM, Philippe Mathieu-Daudé wrote:
> Hi Janosh,
> 
> On 11/22/19 8:52 AM, Janosch Frank wrote:
>> Let's move the resets into one function and switch by type, so we can
>> use fallthroughs for shared reset actions.
>>
>> Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
>> ---
>>   target/s390x/cpu.c | 110 ++++++++++++++++++++-------------------------
>>   1 file changed, 48 insertions(+), 62 deletions(-)
>>
>> diff --git a/target/s390x/cpu.c b/target/s390x/cpu.c
>> index 3abe7e80fd..556afecbc1 100644
>> --- a/target/s390x/cpu.c
>> +++ b/target/s390x/cpu.c
>> @@ -82,67 +82,52 @@ static void s390_cpu_load_normal(CPUState *s)
>>   }
>>   #endif
>>   
>> -/* S390CPUClass::cpu_reset() */
>> -static void s390_cpu_reset(CPUState *s)
>> +typedef enum cpu_reset_type {
>> +    S390_CPU_RESET_NORMAL,
>> +    S390_CPU_RESET_INITIAL,
>> +    S390_CPU_RESET_CLEAR,
>> +} cpu_reset_type;
>> +
>> +static void s390_cpu_reset(CPUState *s, cpu_reset_type type)
>>   {
>>       S390CPU *cpu = S390_CPU(s);
>>       S390CPUClass *scc = S390_CPU_GET_CLASS(cpu);
>>       CPUS390XState *env = &cpu->env;
>>   
>> -    env->pfault_token = -1UL;
>> -    env->bpbc = false;
>>       scc->parent_reset(s);
>>       cpu->env.sigp_order = 0;
>>       s390_cpu_set_state(S390_CPU_STATE_STOPPED, cpu);
>> -}
>>   
>> -/* S390CPUClass::initial_reset() */
>> -static void s390_cpu_initial_reset(CPUState *s)
>> -{
>> -    S390CPU *cpu = S390_CPU(s);
>> -    CPUS390XState *env = &cpu->env;
>> +    /* Set initial values after clearing */
>> +    switch (type) {
>> +    case S390_CPU_RESET_CLEAR:
>> +        memset(env, 0, offsetof(CPUS390XState, start_initial_reset_fields));
>> +        /* Fallthrough */
>> +    case S390_CPU_RESET_INITIAL:
>> +        memset(&env->start_initial_reset_fields, 0,
>> +               offsetof(CPUS390XState, end_reset_fields) -
>> +               offsetof(CPUS390XState, start_initial_reset_fields));
>> +        /* architectured initial values for CR 0 and 14 */
>> +        env->cregs[0] = CR0_RESET;
>> +        env->cregs[14] = CR14_RESET;
>>   
>> -    s390_cpu_reset(s);
>> -    /* initial reset does not clear everything! */
>> -    memset(&env->start_initial_reset_fields, 0,
>> -        offsetof(CPUS390XState, end_reset_fields) -
>> -        offsetof(CPUS390XState, start_initial_reset_fields));
>> -
>> -    /* architectured initial values for CR 0 and 14 */
>> -    env->cregs[0] = CR0_RESET;
>> -    env->cregs[14] = CR14_RESET;
>> -
>> -    /* architectured initial value for Breaking-Event-Address register */
>> -    env->gbea = 1;
>> -
>> -    env->pfault_token = -1UL;
>> -
>> -    /* tininess for underflow is detected before rounding */
>> -    set_float_detect_tininess(float_tininess_before_rounding,
>> -                              &env->fpu_status);
>> +        /* architectured initial value for Breaking-Event-Address register */
>> +        env->gbea = 1;
>> +        /* tininess for underflow is detected before rounding */
>> +        set_float_detect_tininess(float_tininess_before_rounding,
>> +                                  &env->fpu_status);
>> +        /* Fallthrough */
>> +    case S390_CPU_RESET_NORMAL:
>> +        env->pfault_token = -1UL;
>> +        env->bpbc = false;
>> +        break;
>> +    }
>>   
>>       /* Reset state inside the kernel that we cannot access yet from QEMU. */
>> -    if (kvm_enabled()) {
>> -        kvm_s390_reset_vcpu(cpu);
>> +    if (kvm_enabled() && (type == S390_CPU_RESET_CLEAR ||
>> +                          type == S390_CPU_RESET_INITIAL)) {
>> +            kvm_s390_reset_vcpu(cpu);
>>       }
>> -}
>> -
>> -/* CPUClass:reset() */
>> -static void s390_cpu_full_reset(CPUState *s)
>> -{
>> -    S390CPU *cpu = S390_CPU(s);
>> -    S390CPUClass *scc = S390_CPU_GET_CLASS(cpu);
>> -    CPUS390XState *env = &cpu->env;
>> -
>> -    scc->parent_reset(s);
>> -    cpu->env.sigp_order = 0;
>> -    s390_cpu_set_state(S390_CPU_STATE_STOPPED, cpu);
>> -
>> -    memset(env, 0, offsetof(CPUS390XState, end_reset_fields));
>> -
>> -    /* architectured initial values for CR 0 and 14 */
>> -    env->cregs[0] = CR0_RESET;
>> -    env->cregs[14] = CR14_RESET;
>>   
>>   #if defined(CONFIG_USER_ONLY)
>>       /* user mode should always be allowed to use the full FPU */
>> @@ -151,20 +136,21 @@ static void s390_cpu_full_reset(CPUState *s)
>>           env->cregs[0] |= CR0_VECTOR;
>>       }
>>   #endif
>> +}
>>   
>> -    /* architectured initial value for Breaking-Event-Address register */
>> -    env->gbea = 1;
>> +static void s390_cpu_reset_normal(CPUState *s)
>> +{
>> +    return s390_cpu_reset(s, S390_CPU_RESET_NORMAL);
>> +}
>>   
>> -    env->pfault_token = -1UL;
>> +static void s390_cpu_reset_initial(CPUState *s)
>> +{
>> +    return s390_cpu_reset(s, S390_CPU_RESET_INITIAL);
>> +}
>>   
>> -    /* tininess for underflow is detected before rounding */
>> -    set_float_detect_tininess(float_tininess_before_rounding,
>> -                              &env->fpu_status);
>> -
>> -    /* Reset state inside the kernel that we cannot access yet from QEMU. */
>> -    if (kvm_enabled()) {
>> -        kvm_s390_reset_vcpu(cpu);
>> -    }
>> +static void s390_cpu_reset_clear(CPUState *s)
>> +{
>> +    return s390_cpu_reset(s, S390_CPU_RESET_CLEAR);
>>   }
>>   
>>   #if !defined(CONFIG_USER_ONLY)
>> @@ -473,9 +459,9 @@ static void s390_cpu_class_init(ObjectClass *oc, void *data)
>>   #if !defined(CONFIG_USER_ONLY)
>>       scc->load_normal = s390_cpu_load_normal;
>>   #endif
>> -    scc->cpu_reset = s390_cpu_reset;
>> -    scc->initial_cpu_reset = s390_cpu_initial_reset;
>> -    cc->reset = s390_cpu_full_reset;
>> +    scc->cpu_reset = s390_cpu_reset_normal;
>> +    scc->initial_cpu_reset = s390_cpu_reset_initial;
>> +    cc->reset = s390_cpu_reset_clear;
>>       cc->class_by_name = s390_cpu_class_by_name,
>>       cc->has_work = s390_cpu_has_work;
>>   #ifdef CONFIG_TCG
>>
> 
> This is a nice cleanup, but the patch is hard to digest.
> Maybe you can split it in 3, one patch for each cpu_reset_type.
> 
> Regards,
> 
> Phil.
> 

I'll try to split it up.



[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 833 bytes --]