Re: [RFC PATCH 04/10] ppc/pnv: specialise init for powernv8/9/10 machines

["Nicholas Piggin" <npiggin@gmail.com>]

On Tue May 28, 2024 at 5:45 PM AEST, Cédric Le Goater wrote:
> On 5/28/24 09:10, Harsh Prateek Bora wrote:
> > Hi Nick,
> > 
> > On 5/26/24 17:56, Nicholas Piggin wrote:
> >> This will allow different settings and checks for different
> >> machine types with later changes.
> >>
> >> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
> >> ---
> >>   hw/ppc/pnv.c | 35 ++++++++++++++++++++++++++++++-----
> >>   1 file changed, 30 insertions(+), 5 deletions(-)
> >>
> >> diff --git a/hw/ppc/pnv.c b/hw/ppc/pnv.c
> >> index 6e3a5ccdec..a706de2e36 100644
> >> --- a/hw/ppc/pnv.c
> >> +++ b/hw/ppc/pnv.c
> >> @@ -976,11 +976,6 @@ static void pnv_init(MachineState *machine)
> >>       pnv->num_chips =
> >>           machine->smp.max_cpus / (machine->smp.cores * machine->smp.threads);
> >> -    if (machine->smp.threads > 8) {
> >> -        error_report("Cannot support more than 8 threads/core "
> >> -                     "on a powernv machine");
> >> -        exit(1);
> >> -    }
> >>       if (!is_power_of_2(machine->smp.threads)) {
> >>           error_report("Cannot support %d threads/core on a powernv"
> >>                        "machine because it must be a power of 2",
> >> @@ -1076,6 +1071,33 @@ static void pnv_init(MachineState *machine)
> >>       }
> >>   }
> >> +static void pnv_power8_init(MachineState *machine)
> >> +{
> >> +    if (machine->smp.threads > 8) {
> >> +        error_report("Cannot support more than 8 threads/core "
> >> +                     "on a powernv POWER8 machine");
> > 
> > We could use mc->desc for machine name above, so that ..
> > 
> >> +        exit(1);
> >> +    }
> > 
> > with this patch, we can reuse p8 init for both p9 and p10 (and not just reuse p9 for p10 with hard coded string?).
>
> Good idea. You could add a 'max_smt' attribute to PnvMachineClass to limit
> POWER8 to one.

Okay I'll see how that goes. Good suggestions.

Thanks,
Nick