Re: [kvm-unit-tests PATCH 4/5] s390x: smp: Allocate memory in DMA31 space

[Claudio Imbrenda <imbrenda@linux.ibm.com>]

On Fri, 14 Jan 2022 13:50:52 +0100
Nico Boehr <nrb@linux.ibm.com> wrote:

> On Fri, 2022-01-14 at 10:02 +0000, Janosch Frank wrote:
> > The store status at address order works with 31 bit addresses so
> > let's
> > use them.
> > 
> > Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
> > ---
> >  s390x/smp.c | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> > 
> > diff --git a/s390x/smp.c b/s390x/smp.c
> > index 32f128b3..c91f170b 100644
> > --- a/s390x/smp.c
> > +++ b/s390x/smp.c  
> 
> [...]
> 
> > @@ -244,7 +244,7 @@ static void test_func_initial(void)
> >  
> >  static void test_reset_initial(void)
> >  {
> > -       struct cpu_status *status = alloc_pages(0);
> > +       struct cpu_status *status = alloc_pages_flags(1, AREA_DMA31);  
> 
> Why do we need two pages now?

actually, wait.....

        struct cpu_status *status = alloc_pages_flags(1, AREA_DMA31);
        uint32_t r;

        report_prefix_push("store status at address");
        memset(status, 0, PAGE_SIZE * 2);

we were allocating one page, and using 2!

@Janosch do we need 1 or 2 pages?