Re: [PATCH-for-6.0] hw/ppc/mac_newworld: Restrict RAM to 2 GiB

[David Gibson]

On Wed, Apr 07, 2021 at 03:44:35PM +0200, Philippe Mathieu-Daudé wrote:
> On 4/7/21 3:11 PM, Mark Cave-Ayland wrote:
> > On 06/04/2021 09:48, Philippe Mathieu-Daudé wrote:
> > 
> >> On Mac99 and newer machines, the Uninorth PCI host bridge maps
> >> the PCI hole region at 2GiB, so the RAM area beside 2GiB is not
> >> accessible by the CPU. Restrict the memory to 2GiB to avoid
> >> problems such the one reported in the buglink.
> >>
> >> Buglink: https://bugs.launchpad.net/qemu/+bug/1922391
> >> Reported-by: Håvard Eidnes <he@NetBSD.org>
> >> Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
> >> ---
> >>   hw/ppc/mac_newworld.c | 4 ++++
> >>   1 file changed, 4 insertions(+)
> >>
> >> diff --git a/hw/ppc/mac_newworld.c b/hw/ppc/mac_newworld.c
> >> index 21759628466..d88b38e9258 100644
> >> --- a/hw/ppc/mac_newworld.c
> >> +++ b/hw/ppc/mac_newworld.c
> >> @@ -157,6 +157,10 @@ static void ppc_core99_init(MachineState *machine)
> >>       }
> >>         /* allocate RAM */
> >> +    if (machine->ram_size > 2 * GiB) {
> >> +        error_report("RAM size more than 2 GiB is not supported");
> >> +        exit(1);
> >> +    }
> >>       memory_region_add_subregion(get_system_memory(), 0, machine->ram);
> >>         /* allocate and load firmware ROM */
> > 
> > I think the patch is correct, however I'm fairly sure that the default
> > g3beige machine also has the PCI hole located at 0x80000000 so the same
> > problem exists there too.
> > 
> > Also are you keen to get this merged for 6.0? It doesn't seem to solve a
> > security issue/release blocker and I'm sure the current behaviour has
> > been like this for a long time...
> 
> No problem. I wanted to revisit this bug anyway, I realized during the
> night, while this patch makes QEMU exit cleanly, it hides the bug which
> is likely in TYPE_MACIO_IDE (I haven't tried Håvard's full
> reproducer).

Ah, given the comments above, I've pulled this out of ppc-for-6.0 and
moved it to ppc-for-6.1.

> 
> Regards,
> 
> Phil.
> 

-- 
David Gibson                    | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au  | minimalist, thank you.  NOT _the_ _other_
                                | _way_ _around_!
http://www.ozlabs.org/~dgibson

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