Re: [PATCH v10 10/16] s390x: protvirt: Set guest IPL PSW

[Janosch Frank]

On 3/18/20 7:00 PM, Cornelia Huck wrote:
> On Wed, 18 Mar 2020 10:30:41 -0400
> Janosch Frank <address@hidden> wrote:
> 
>> Handling of CPU reset and setting of the IPL psw from guest storage at
>> offset 0 is done by a Ultravisor call. Let's only fetch it if
>> necessary.
>>
>> Signed-off-by: Janosch Frank <address@hidden>
>> Reviewed-by: Thomas Huth <address@hidden>
>> Reviewed-by: David Hildenbrand <address@hidden>
>> Reviewed-by: Christian Borntraeger <address@hidden>
>> Reviewed-by: Claudio Imbrenda <address@hidden>
>> ---
>>  target/s390x/cpu.c | 26 +++++++++++++++++---------
>>  1 file changed, 17 insertions(+), 9 deletions(-)
>>
>> diff --git a/target/s390x/cpu.c b/target/s390x/cpu.c
>> index 84029f14814b4980..3ec7d4b2ec1e938f 100644
>> --- a/target/s390x/cpu.c
>> +++ b/target/s390x/cpu.c
>> @@ -78,16 +78,24 @@ static bool s390_cpu_has_work(CPUState *cs)
>>  static void s390_cpu_load_normal(CPUState *s)
>>  {
>>      S390CPU *cpu = S390_CPU(s);
>> -    uint64_t spsw = ldq_phys(s->as, 0);
>> -
>> -    cpu->env.psw.mask = spsw & PSW_MASK_SHORT_CTRL;
>> -    /*
>> -     * Invert short psw indication, so SIE will report a specification
>> -     * exception if it was not set.
>> -     */
>> -    cpu->env.psw.mask ^= PSW_MASK_SHORTPSW;
>> -    cpu->env.psw.addr = spsw & PSW_MASK_SHORT_ADDR;
>> +    uint64_t spsw;
>>  
>> +    if (!s390_is_pv()) {
>> +        spsw = ldq_phys(s->as, 0);
>> +        cpu->env.psw.mask = spsw & PSW_MASK_SHORT_CTRL;
>> +        /*
>> +         * Invert short psw indication, so SIE will report a specification
>> +         * exception if it was not set.
>> +         */
>> +        cpu->env.psw.mask ^= PSW_MASK_SHORTPSW;
>> +        cpu->env.psw.addr = spsw & PSW_MASK_SHORT_ADDR;
>> +    } else {
>> +        /*
>> +         * Firmware requires us to set the load state before we set
>> +         * the cpu to operating on protected guests.
>> +         */
>> +        s390_cpu_set_state(S390_CPU_STATE_LOAD, cpu);
> 
> We probably could do that unconditionally, but this is fine.

As far as I know the load state is only used by lpar and for a normal
KVM guest it doesn't really make sense.

Specification for that state is however a bit sparse.

> 
>> +    }
>>      s390_cpu_set_state(S390_CPU_STATE_OPERATING, cpu);
>>  }
>>  #endif
> 
> Reviewed-by: Cornelia Huck <address@hidden>

Thanks!

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