Re: [PATCH 07/15] s390x: protvirt: Handle diag 308 subcodes 0,1,3,4

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

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On 11/21/19 2:50 PM, Cornelia Huck wrote:
> On Wed, 20 Nov 2019 06:43:26 -0500
> Janosch Frank <frankja@linux.ibm.com> wrote:
> 
>> Now that we know the protection state off the cpus, we can start
>> handling all diag 308 subcodes in the protected state.
> 
> "As we now have access to the protection state of the cpus, we can
> implement special handling of diag 308 subcodes for cpus in the
> protected state."
> 
> ?

Sure

> 
>>
>> For subcodes 0 and 1 we need to unshare all pages before continuing,
>> so the guest doesn't accidently 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.
>>
>> Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
>> ---
>>  hw/s390x/s390-virtio-ccw.c | 30 +++++++++++++++++++++++++++---
>>  target/s390x/diag.c        |  4 ++++
>>  2 files changed, 31 insertions(+), 3 deletions(-)
>>
>> diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
>> index 7262453616..6fd50b4c42 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;
>> +    }
>> +    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);
>> @@ -332,29 +347,38 @@ static void s390_machine_reset(MachineState *machine)
>>      s390_cmma_reset();
>>  
>>      cpu = S390_CPU(cs);
>> +    env = &cpu->env;
>>  
>>      switch (reset_type) {
>>      case S390_RESET_MODIFIED_CLEAR:  /* Subcode 0 */
>> +        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();
> 
> This also switches the order in which different parts are reset for
> normal guests. I presume that order doesn't matter here?

I don't think that the order is specified in the POP, it is however
specified for protected VMs...

> 
>>          run_on_cpu(cs, s390_do_cpu_load_normal, RUN_ON_CPU_NULL);
>>          break;
>>      case S390_RESET_LOAD_NORMAL: /* Subcode 1*/
> 
> missing blank before */ (introduced in a previous patch)

Will fix

> 
> 
>> +        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();
>>          run_on_cpu(cs, s390_do_cpu_initial_reset, RUN_ON_CPU_NULL);
>>          run_on_cpu(cs, s390_do_cpu_load_normal, RUN_ON_CPU_NULL);
>>          break;
>>      case S390_RESET_EXTERNAL:
> 
> Annotate this with the subcode as well? (in the patch introducing it)

Sure

> 
>>      case S390_RESET_REIPL: /* Subcode 4 */
>> +        if (env->pv) {
>> +            CPU_FOREACH(t) {
>> +                s390_pv_vcpu_destroy(t);
>> +            }
>> +            s390_pv_vm_destroy();
>> +        }
>>          qemu_devices_reset();
>>          s390_crypto_reset();
>>          /* configure and start the ipl CPU only */
>> diff --git a/target/s390x/diag.c b/target/s390x/diag.c
>> index 32049bb4ee..db6d79cef3 100644
>> --- a/target/s390x/diag.c
>> +++ b/target/s390x/diag.c
>> @@ -68,6 +68,10 @@ int handle_diag_288(CPUS390XState *env, uint64_t r1, uint64_t r3)
>>  static int diag308_parm_check(CPUS390XState *env, uint64_t r1, uint64_t addr,
>>                                uintptr_t ra, bool write)
>>  {
>> +    /* Handled by the Ultravisor */
>> +    if (env->pv) {
>> +        return 0;
>> +    }
>>      if ((r1 & 1) || (addr & ~TARGET_PAGE_MASK)) {
>>          s390_program_interrupt(env, PGM_SPECIFICATION, ra);
>>          return -EINVAL;
> 



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