Re: [PATCH v10 09/16] s390x: protvirt: SCLP interpretation

[Janosch Frank]

On 3/19/20 1:09 PM, Cornelia Huck wrote:
> On Wed, 18 Mar 2020 10:30:40 -0400
> Janosch Frank <address@hidden> 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>
>> ---
>>  hw/s390x/sclp.c         | 65 ++++++++++++++++++++++++++++++++++-------
>>  include/hw/s390x/sclp.h |  2 ++
>>  target/s390x/kvm.c      | 25 ++++++++++++----
>>  3 files changed, 76 insertions(+), 16 deletions(-)
>>
>> diff --git a/hw/s390x/sclp.c b/hw/s390x/sclp.c
>> index af0bfbc2eca74767..6486890fecea4b3c 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 +209,43 @@ 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 number of calls is permitted by the
>> +     * Ultravisor and we support all of them, so we don't check for
> 
> This is no longer true, no?

Right, I just removed the comment.

> 
>> +     * them. All other specification exceptions are also interpreted
>> +     * by the Ultravisor and hence never cause an exit we need to
>> +     * handle.
>> +     *
>> +     * Setting the CC is also done by the Ultravisor.
>> +     */
>> +    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();
>

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