Re: [PATCH 2/3] hw/hppa/machine: Do not limit the RAM to 3840MB

[Philippe Mathieu-Daudé]

On 1/9/20 11:15 AM, Igor Mammedov wrote:
> On Wed,  8 Jan 2020 19:14:24 +0100
> Philippe Mathieu-Daudé <address@hidden> wrote:
>
> > The hardware expects DIMM slots of 1 or 2 GB, allowing up to
> > 4 GB of memory. Accept the same amount of memory the hardware
> > can deal with.
> >
> > The CPU doesn't have access to the RAM mapped in the
> > [0xf0000000 - 0xf1000000] range because this is the PDC area
> > (Processor Dependent Code) where the firmware is loaded.
> > To keep this region with higher priority than the RAM, lower
> > the RAM priority. The PDC will overlap it.
> >
> > Signed-off-by: Philippe Mathieu-Daudé <address@hidden>
> Looks good to me (since board doesn't fix up ram_size and uses
> whatever user specified, proper support for 4Gb could be done on top later).
>
> > ---
> >   hw/hppa/machine.c | 11 +++++------
> >   1 file changed, 5 insertions(+), 6 deletions(-)
> >
> > diff --git a/hw/hppa/machine.c b/hw/hppa/machine.c
> > index 6775d879f8..d10c967d06 100644
> > --- a/hw/hppa/machine.c
> > +++ b/hw/hppa/machine.c
> > @@ -90,16 +90,15 @@ static void machine_hppa_init(MachineState *machine)
> >           g_free(name);
> >       }
> >   
> > -    /* Limit main memory. */
> > -    if (ram_size > FIRMWARE_START) {
> > -        machine->ram_size = ram_size = FIRMWARE_START;
> > -    }
> > -
> >       /* Main memory region. */
> > +    if (machine->ram_size > 4 * GiB) {
> Could it break a build on 32-bit mingw host?
> (machine->ram_size is 32-bit on that host and condition would be
> always false, tripping -Werror)

By following Helge tip to restrict to 3GB, v2 of this series doesn't 
have this problem :)

> that's why I've worked around it using local uint64_t in the last version
>   "[PATCH v3 43/86] hppa: allow max ram size upto 4Gb"
> coincidentally that would get rid of global ram_size usage
> and leave only machine->ram_size on this board.

Since I was not sure how you wanted to clean this, I haven't modified 
it. We can add it on top but I'd rather do a whole codebase cleanup.

Note: you also need to modify hppa_machine_reset() by using ms->ram_size 
instead.

> > +        error_report("RAM size of 4GB or more is not supported");
> > +        exit(EXIT_FAILURE);
> > +    }
> >       ram_region = g_new(MemoryRegion, 1);
> >       memory_region_allocate_system_memory(ram_region, OBJECT(machine),
> >                                            "ram", ram_size);
> > -    memory_region_add_subregion(addr_space, 0, ram_region);
> > +    memory_region_add_subregion_overlap(addr_space, 0, ram_region, -1);
> >   
> >       /* Init Dino (PCI host bus chip).  */
> >       pci_bus = dino_init(addr_space, &rtc_irq, &serial_irq);