Re: [PATCH v6 10/18] s390x: protvirt: SCLP interpretation

[David Hildenbrand <david@redhat.com>]

On 04.03.20 12:42, Janosch Frank wrote:
> SCLP for a protected guest is done over the SIDAD, so we need to use
> the s390_cpu_virt_mem_* functions to access the SIDAD instead of guest

nope :)

s390_cpu_pv_mem_*

> 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.

Please add that as a comment to SCLP_PV_DUMMY_ADDR.

> 
> Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
> ---
>  hw/s390x/sclp.c         | 17 +++++++++++++++++
>  include/hw/s390x/sclp.h |  2 ++
>  target/s390x/kvm.c      |  5 +++++
>  3 files changed, 24 insertions(+)
> 
> diff --git a/hw/s390x/sclp.c b/hw/s390x/sclp.c
> index af0bfbc2ec..5136f5fcbe 100644
> --- a/hw/s390x/sclp.c
> +++ b/hw/s390x/sclp.c
> @@ -193,6 +193,23 @@ static void sclp_execute(SCLPDevice *sclp, SCCB *sccb, uint32_t code)
>      }
>  }
>  
> +#define SCLP_PV_DUMMY_ADDR 0x4000

Should we move that to sclp_c->service_interrupt instead and document it
properly?

Or what about providing a

sclp_c->service_interrupt_pv(sclp) that handles this internally?

> +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);

I assume it's valid to always read the full SCCB length?

> +    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 43fc0c088b..a4cbdc5fc6 100644
> --- a/target/s390x/kvm.c
> +++ b/target/s390x/kvm.c
> @@ -1226,6 +1226,11 @@ static void kvm_sclp_service_call(S390CPU *cpu, struct kvm_run *run,
>      sccb = env->regs[ipbh0 & 0xf];
>      code = env->regs[(ipbh0 & 0xf0) >> 4];
>  
> +    if (run->s390_sieic.icptcode == ICPT_PV_INSTR) {

I still somewhat prefer checking for env->pv instead - similar to patch #9.


-- 
Thanks,

David / dhildenb