Re: [PATCH v11 09/16] s390x: protvirt: SCLP interpretation

[Christian Borntraeger]

On 19.03.20 14:19, 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>
> Reviewed-by: David Hildenbrand <address@hidden>
> Reviewed-by: Claudio Imbrenda <address@hidden>
> Reviewed-by: Cornelia Huck <address@hidden>

Reviewed-by: Christian Borntraeger <address@hidden>

series looks good to me.


> ---
>  hw/s390x/sclp.c         | 56 +++++++++++++++++++++++++++++++++--------
>  include/hw/s390x/sclp.h |  2 ++
>  target/s390x/kvm.c      | 25 ++++++++++++++----
>  3 files changed, 67 insertions(+), 16 deletions(-)
> 
> diff --git a/hw/s390x/sclp.c b/hw/s390x/sclp.c
> index af0bfbc2eca74767..d8ae207731f1060a 100644
> --- a/hw/s390x/sclp.c
> +++ b/hw/s390x/sclp.c
> @@ -33,6 +33,22 @@ static inline SCLPDevice *get_sclp_device(void)
>      return sclp;
>  }
>  
> +static inline bool sclp_command_code_valid(uint32_t code)
> +{
> +    switch (code & SCLP_CMD_CODE_MASK) {
> +    case SCLP_CMDW_READ_SCP_INFO:
> +    case SCLP_CMDW_READ_SCP_INFO_FORCED:
> +    case SCLP_CMDW_READ_CPU_INFO:
> +    case SCLP_CMDW_CONFIGURE_IOA:
> +    case SCLP_CMDW_DECONFIGURE_IOA:
> +    case SCLP_CMD_READ_EVENT_DATA:
> +    case SCLP_CMD_WRITE_EVENT_DATA:
> +    case SCLP_CMD_WRITE_EVENT_MASK:
> +        return true;
> +    }
> +    return false;
> +}
> +
>  static void prepare_cpu_entries(SCLPDevice *sclp, CPUEntry *entry, int 
> *count)
>  {
>      MachineState *ms = MACHINE(qdev_get_machine());
> @@ -193,6 +209,34 @@ 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);
> +
> +    s390_cpu_pv_mem_read(env_archcpu(env), 0, &work_sccb, sccb_len);
> +
> +    if (!sclp_command_code_valid(code)) {
> +        work_sccb.h.response_code = 
> cpu_to_be16(SCLP_RC_INVALID_SCLP_COMMAND);
> +        goto out_write;
> +    }
> +
> +    sclp_c->execute(sclp, &work_sccb, code);
> +out_write:
> +    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();
> @@ -225,17 +269,7 @@ int sclp_service_call(CPUS390XState *env, uint64_t sccb, 
> uint32_t code)
>          return -PGM_SPECIFICATION;
>      }
>  
> -    switch (code & SCLP_CMD_CODE_MASK) {
> -    case SCLP_CMDW_READ_SCP_INFO:
> -    case SCLP_CMDW_READ_SCP_INFO_FORCED:
> -    case SCLP_CMDW_READ_CPU_INFO:
> -    case SCLP_CMDW_CONFIGURE_IOA:
> -    case SCLP_CMDW_DECONFIGURE_IOA:
> -    case SCLP_CMD_READ_EVENT_DATA:
> -    case SCLP_CMD_WRITE_EVENT_DATA:
> -    case SCLP_CMD_WRITE_EVENT_MASK:
> -        break;
> -    default:
> +    if (!sclp_command_code_valid(code)) {
>          work_sccb.h.response_code = 
> cpu_to_be16(SCLP_RC_INVALID_SCLP_COMMAND);
>          goto out_write;
>      }
> diff --git a/include/hw/s390x/sclp.h b/include/hw/s390x/sclp.h
> index cd7b24359f28deb4..822eff4396ff5dde 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 462a1d70ee78104c..6b7819d2c51a111c 100644
> --- a/target/s390x/kvm.c
> +++ b/target/s390x/kvm.c
> @@ -1233,12 +1233,27 @@ 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:
> +        g_assert(s390_is_pv());
> +        /* The notification intercepts are currently handled by KVM */
> +        error_report("unexpected SCLP PV notification");
> +        exit(1);
> +        break;
> +    case ICPT_PV_INSTR:
> +        g_assert(s390_is_pv());
> +        sclp_service_call_protected(env, sccb, code);
> +        /* Setting the CC is done by the Ultravisor. */
> +        break;
> +    case ICPT_INSTRUCTION:
> +        g_assert(!s390_is_pv());
> +        r = sclp_service_call(env, sccb, code);
> +        if (r < 0) {
> +            kvm_s390_program_interrupt(cpu, -r);
> +            return;
> +        }
> +        setcc(cpu, r);
>      }
> -    setcc(cpu, r);
>  }
>  
>  static int handle_b2(S390CPU *cpu, struct kvm_run *run, uint8_t ipa1)
>