Re: [PATCH v7 08/15] s390x: protvirt: SCLP interpretation

[Janosch Frank]

On 3/9/20 4:27 PM, David Hildenbrand wrote:
> On 09.03.20 12:21, Janosch Frank wrote:
>> SCLP for a protected guest is done over the SIDAD, so we need to use
>> the s390_cpu_pv_mem_* functions to access the SIDAD instead of guest
>> memory when reading/writing SCBs.
>>
>> To not confuse the sclp emulation, we set 0x4000 as the SCCB address,
>> since the function that injects the sclp external interrupt would
>> reject a zero sccb address.
>>
>> Signed-off-by: Janosch Frank <address@hidden>
>> ---
>>  hw/s390x/sclp.c         | 28 ++++++++++++++++++++++++++++
>>  include/hw/s390x/sclp.h |  2 ++
>>  target/s390x/kvm.c      | 21 ++++++++++++++++-----
>>  3 files changed, 46 insertions(+), 5 deletions(-)
>>
>> diff --git a/hw/s390x/sclp.c b/hw/s390x/sclp.c
>> index af0bfbc2ec..b4bc2dd659 100644
>> --- a/hw/s390x/sclp.c
>> +++ b/hw/s390x/sclp.c
>> @@ -193,6 +193,34 @@ static void sclp_execute(SCLPDevice *sclp, SCCB *sccb, 
>> uint32_t code)
>>      }
>>  }
>>  
>> +/*
>> +* We only need the address to have something valid for the
>> +* service_interrupt call.
>> +*/
>> +#define SCLP_PV_DUMMY_ADDR 0x4000
>> +int sclp_service_call_protected(CPUS390XState *env, uint64_t sccb,
>> +                                uint32_t code)
>> +{
>> +    SCLPDevice *sclp = get_sclp_device();
>> +    SCLPDeviceClass *sclp_c = SCLP_GET_CLASS(sclp);
>> +    SCCB work_sccb;
>> +    hwaddr sccb_len = sizeof(SCCB);
>> +
>> +    /*
>> +     * Only a very limited amount of calls is permitted by the
>> +     * Ultravisor and we support all of them, so we don't check for
>> +     * them. All other specification exceptions are also interpreted
>> +     * by the Ultravisor and hence never cause an exit we need to
>> +     * handle.
>> +     */
>> +    s390_cpu_pv_mem_read(env_archcpu(env), 0, &work_sccb, sccb_len);
>> +    sclp_c->execute(sclp, &work_sccb, code);
>> +    s390_cpu_pv_mem_write(env_archcpu(env), 0, &work_sccb,
>> +                          be16_to_cpu(work_sccb.h.length));
>> +    sclp_c->service_interrupt(sclp, SCLP_PV_DUMMY_ADDR);
>> +    return 0;
>> +}
>> +
>>  int sclp_service_call(CPUS390XState *env, uint64_t sccb, uint32_t code)
>>  {
>>      SCLPDevice *sclp = get_sclp_device();
>> diff --git a/include/hw/s390x/sclp.h b/include/hw/s390x/sclp.h
>> index c54413b78c..c0a3faa37d 100644
>> --- a/include/hw/s390x/sclp.h
>> +++ b/include/hw/s390x/sclp.h
>> @@ -217,5 +217,7 @@ void s390_sclp_init(void);
>>  void sclp_service_interrupt(uint32_t sccb);
>>  void raise_irq_cpu_hotplug(void);
>>  int sclp_service_call(CPUS390XState *env, uint64_t sccb, uint32_t code);
>> +int sclp_service_call_protected(CPUS390XState *env, uint64_t sccb,
>> +                                uint32_t code);
>>  
>>  #endif
>> diff --git a/target/s390x/kvm.c b/target/s390x/kvm.c
>> index 295ed12a38..5c7757ac28 100644
>> --- a/target/s390x/kvm.c
>> +++ b/target/s390x/kvm.c
>> @@ -1226,12 +1226,23 @@ static void kvm_sclp_service_call(S390CPU *cpu, 
>> struct kvm_run *run,
>>      sccb = env->regs[ipbh0 & 0xf];
>>      code = env->regs[(ipbh0 & 0xf0) >> 4];
>>  
>> -    r = sclp_service_call(env, sccb, code);
>> -    if (r < 0) {
>> -        kvm_s390_program_interrupt(cpu, -r);
>> -        return;
>> +    switch (run->s390_sieic.icptcode) {
>> +    case ICPT_PV_INSTR_NOTIFICATION:
>> +        /* The notification intercepts are currently handled by KVM */
>> +        fprintf(stderr, "unexpected SCLP PV notification\n");
> 
> Maybe g_assert(env->pv);
> 
> error_report() ?

Sure, I just followed suit with the other aborts in this file.

> 
>> +        exit(1);
>> +        break;
>> +    case ICPT_PV_INSTR:
>> +        sclp_service_call_protected(env, sccb, code);
>> +        break;
>> +    case ICPT_INSTRUCTION:
> 
> Maybe g_assert(!env->pv);
> 
>> +        r = sclp_service_call(env, sccb, code);
>> +        if (r < 0) {
>> +            kvm_s390_program_interrupt(cpu, -r);
>> +            return;
>> +        }
>> +        setcc(cpu, r);
>>      }
>> -    setcc(cpu, r);
> 
> What about the cc in case of ICPT_PV_INSTR?

Set to 0 by the Ultravisor/SIE

> 
>>  }
>>  
>>  static int handle_b2(S390CPU *cpu, struct kvm_run *run, uint8_t ipa1)
>>
> 
>

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