Re: [PATCH v3 1/1] vl/s390x: fixup ram sizes for compat machines

[Cornelia Huck <cohuck@redhat.com>]

On Thu, 2 Apr 2020 11:25:34 +0200
Christian Borntraeger <borntraeger@de.ibm.com> wrote:

> On 02.04.20 11:22, Cornelia Huck wrote:
> > On Wed, 1 Apr 2020 15:14:12 +0200
> > David Hildenbrand <david@redhat.com> wrote:
> >   
> >> On 01.04.20 14:37, Christian Borntraeger wrote:  
> >   
> >>> +static ram_addr_t s390_fixup_ram_size(ram_addr_t sz)
> >>> +{
> >>> +    /* same logic as in sclp.c */
> >>> +    int increment_size = 20;
> >>> +    ram_addr_t newsz;
> >>> +
> >>> +    while ((sz >> increment_size) > MAX_STORAGE_INCREMENTS) {
> >>> +        increment_size++;
> >>> +    }
> >>> +    newsz = sz >> increment_size << increment_size;
> >>> +
> >>> +    if (sz != newsz) {
> >>> +        qemu_printf("Ram size %" PRIu64 "MB was fixed up to %" PRIu64
> >>> +                    "MB to match machine restrictions. Consider updating "
> >>> +                    "the guest definition.i\n", sz / MiB, newsz / MiB);    
> >>
> >> Not sure if news/zs will be printed correctly in case ram_addr_t !=
> >> uint64_t.  
> > 
> > RAM_ADDR_FMT might be the right thing to use here?  
> 
> I tried that but it returns a hex value in bytes. This is unusable. Thats why I divided
> by MiB. 

Nod.

> We could simply do an u64 cast?

Not sure if we might end up with "cast to integer of different length"
values on some platforms (that I unfortunately don't have around to
test). I hate that stuff.