Re: [PATCH v2 04/13] s390x: protvirt: Handle diag 308 subcodes 0,1,3,4

[David Hildenbrand <david@redhat.com>]

On 29.11.19 10:48, Janosch Frank wrote:
> Now that we know the protection state off the cpus, we can start
> handling all diag 308 subcodes in the protected state.
> 
> For subcodes 0 and 1 we need to unshare all pages before continuing,
> so the guest doesn't accidentally expose data when dumping.
> 
> For subcode 3/4 we tear down the protected VM and reboot into
> unprotected mode. We do not provide a secure reboot.
> 
> Before we can do the unshare calls, we need to mark all cpus as
> stopped.

This patch should be squashed into the previous one IMHO ...

> 
> Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
> ---
>  hw/s390x/s390-virtio-ccw.c | 31 ++++++++++++++++++++++++++++---
>  target/s390x/diag.c        |  4 ++++
>  2 files changed, 32 insertions(+), 3 deletions(-)
> 
> diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
> index f9481ccace..e2a302398d 100644
> --- a/hw/s390x/s390-virtio-ccw.c
> +++ b/hw/s390x/s390-virtio-ccw.c
> @@ -319,11 +319,26 @@ static inline void s390_do_cpu_ipl(CPUState *cs, run_on_cpu_data arg)
>      s390_cpu_set_state(S390_CPU_STATE_OPERATING, cpu);
>  }
>  
> +static void s390_pv_prepare_reset(CPUS390XState *env)
> +{
> +    CPUState *cs;
> +
> +    if (!env->pv) {
> +        return;
> +    }

I'd suggest doing that check in the callers. (just like e.g., in "case
S390_RESET_REIPL" already)

> +    CPU_FOREACH(cs) {
> +        s390_cpu_set_state(S390_CPU_STATE_STOPPED, S390_CPU(cs));
> +    }
> +    s390_pv_unshare();
> +    s390_pv_perf_clear_reset();
> +}
> +
>  static void s390_machine_reset(MachineState *machine)
>  {
>      enum s390_reset reset_type;
>      CPUState *cs, *t;
>      S390CPU *cpu;
> +    CPUS390XState *env;
>  
>      /* get the reset parameters, reset them once done */
>      s390_ipl_get_reset_request(&cs, &reset_type);
> @@ -332,10 +347,18 @@ static void s390_machine_reset(MachineState *machine)
>      s390_cmma_reset();
>  
>      cpu = S390_CPU(cs);
> +    env = &cpu->env;
>  
>      switch (reset_type) {
>      case S390_RESET_EXTERNAL:
>      case S390_RESET_REIPL:
> +        if (env->pv) {
> +            CPU_FOREACH(t) {
> +                s390_pv_vcpu_destroy(t);
> +            }
> +            s390_pv_vm_destroy();
> +        }
> +
>          qemu_devices_reset();
>          s390_crypto_reset();
>  
> @@ -343,21 +366,23 @@ static void s390_machine_reset(MachineState *machine)
>          run_on_cpu(cs, s390_do_cpu_ipl, RUN_ON_CPU_NULL);
>          break;
>      case S390_RESET_MODIFIED_CLEAR:
> +        subsystem_reset();
> +        s390_crypto_reset();
> +        s390_pv_prepare_reset(env);
>          CPU_FOREACH(t) {
>              run_on_cpu(t, s390_do_cpu_full_reset, RUN_ON_CPU_NULL);
>          }
> -        subsystem_reset();
> -        s390_crypto_reset();
>          run_on_cpu(cs, s390_do_cpu_load_normal, RUN_ON_CPU_NULL);
>          break;
>      case S390_RESET_LOAD_NORMAL:
> +        subsystem_reset();
> +        s390_pv_prepare_reset(env);
>          CPU_FOREACH(t) {
>              if (t == cs) {
>                  continue;
>              }
>              run_on_cpu(t, s390_do_cpu_reset, RUN_ON_CPU_NULL);
>          }
> -        subsystem_reset();

I do wonder if changing the orders here is okay ... why do you have to
move subsystem_reset()?

-- 
Thanks,

David / dhildenb