Re: [PATCH v4 3/6] s390x: Move initial reset

[Thomas Huth <thuth@redhat.com>]

On 27/11/2019 18.50, Janosch Frank wrote:
> Let's move the intial reset into the reset handler and cleanup
> afterwards.
> 
> Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
> Reviewed-by: David Hildenbrand <david@redhat.com>
> ---
>   target/s390x/cpu-qom.h |  2 +-
>   target/s390x/cpu.c     | 44 ++++++++++++++++--------------------------
>   target/s390x/cpu.h     |  2 +-
>   target/s390x/sigp.c    |  2 +-
>   4 files changed, 20 insertions(+), 30 deletions(-)
> 
> diff --git a/target/s390x/cpu-qom.h b/target/s390x/cpu-qom.h
> index f3b71bac67..6f0a12042e 100644
> --- a/target/s390x/cpu-qom.h
> +++ b/target/s390x/cpu-qom.h
> @@ -36,6 +36,7 @@ typedef struct S390CPUDef S390CPUDef;
>   
>   typedef enum cpu_reset_type {
>       S390_CPU_RESET_NORMAL,
> +    S390_CPU_RESET_INITIAL,
>   } cpu_reset_type;
>   
>   /**
> @@ -62,7 +63,6 @@ typedef struct S390CPUClass {
>       void (*parent_reset)(CPUState *cpu);
>       void (*load_normal)(CPUState *cpu);
>       void (*reset)(CPUState *cpu, cpu_reset_type type);
> -    void (*initial_cpu_reset)(CPUState *cpu);
>   } S390CPUClass;
>   
>   typedef struct S390CPU S390CPU;
> diff --git a/target/s390x/cpu.c b/target/s390x/cpu.c
> index 67d6fbfa44..55e2d1fe7b 100644
> --- a/target/s390x/cpu.c
> +++ b/target/s390x/cpu.c
> @@ -94,6 +94,23 @@ static void s390_cpu_reset(CPUState *s, cpu_reset_type type)
>       s390_cpu_set_state(S390_CPU_STATE_STOPPED, cpu);
>   
>       switch (type) {
> +    case S390_CPU_RESET_INITIAL:
> +        /* 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 value for Breaking-Event-Address register */
> +        env->gbea = 1;
> +
> +        /* architectured initial values for CR 0 and 14 */
> +        env->cregs[0] = CR0_RESET;
> +        env->cregs[14] = CR14_RESET;
> +
> +        /* tininess for underflow is detected before rounding */
> +        set_float_detect_tininess(float_tininess_before_rounding,
> +                                  &env->fpu_status);
> +       /* fall through */
>       case S390_CPU_RESET_NORMAL:
>           env->pfault_token = -1UL;
>           env->bpbc = false;
> @@ -101,32 +118,6 @@ static void s390_cpu_reset(CPUState *s, cpu_reset_type type)
>       default:
>           g_assert_not_reached();
>       }
> -}
> -
> -/* S390CPUClass::initial_reset() */
> -static void s390_cpu_initial_reset(CPUState *s)
> -{
> -    S390CPU *cpu = S390_CPU(s);
> -    CPUS390XState *env = &cpu->env;
> -
> -    s390_cpu_reset(s, S390_CPU_RESET_NORMAL);
> -    /* 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);
>   
>       /* Reset state inside the kernel that we cannot access yet from QEMU. */
>       if (kvm_enabled()) {

You're doing the if (kvm_enabled()) now also for S390_CPU_RESET_NORMAL 
... is that OK? It's doing an KVM_S390_INITIAL_RESET ioctl(), so that 
sounds suspicious to me. Don't you have to add a check for type != 
S390_CPU_RESET_NORMAL here?

  Thomas