Re: [PATCH qemu v2 2/3] hw/s390x: add SCLP event type CPI

[Nina Schoetterl-Glausch <nsg@linux.ibm.com>]

On Wed, 2025-03-05 at 19:04 +0100, Thomas Huth wrote:

[...]

> > +
> > +static int write_event_data(SCLPEvent *event, EventBufferHeader *evt_buf_hdr)
> > +{
> > +    ControlProgramIdMsg *cpi = container_of(evt_buf_hdr, ControlProgramIdMsg,
> > +                                            ebh);
> > +    S390CcwMachineState *ms = S390_CCW_MACHINE(qdev_get_machine());
> > +
> > +    ascii_put(ms->cpi.system_type, (char *)cpi->data.system_type, 8);
> > +    ascii_put(ms->cpi.system_name, (char *)cpi->data.system_name, 8);
> > +    ascii_put(ms->cpi.sysplex_name, (char *)cpi->data.sysplex_name, 8);
> > +    ms->cpi.system_level = be64_to_cpu(cpi->data.system_level);
> 
> Can we be confident that system_level is always properly aligned?

It has offset 40 from the start of a heap allocation, so yes, but it is far
from obvious so I wouldn't mind ldq_be_p.

> Otherwise it's maybe better to use ldq_be_p() instead?
> 
>   Thomas
> 
> 

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