Re: [PATCH] hw/i386/pc: fix max_used_gpa for 32-bit systems

[Ani Sinha]

On Mon, Sep 18, 2023 at 8:59 PM David Hildenbrand <david@redhat.com> wrote:
>
> On 18.09.23 17:22, Ani Sinha wrote:
> > On Mon, Sep 18, 2023 at 7:25 PM Ani Sinha <anisinha@redhat.com> wrote:
> >>
> >> 32-bit systems do not have a reserved memory for hole64 but they may have a
> >> reserved memory space for memory hotplug. Since, hole64 starts after the
> >> reserved hotplug memory, the unaligned hole64 start address gives us the
> >> end address for this memory hotplug region that the processor may use.
> >> Fix this. This ensures that the physical address space bound checking works
> >> correctly for 32-bit systems as well.
> >
> > This patch breaks some unit tests. I am not sure why it did not catch
> > it when I tested it before sending.
> > Will have to resend after fixing the tests.
>
> Probably because they supply more memory than the system can actually
> handle? (e.g., -m 4g on 32bit)?

cxl tests are failing for example.

$ ./qemu-system-i386 -display none -machine q35,cxl=on
qemu-system-i386: Address space limit 0xffffffff < 0x1000fffff
phys-bits too low (32)



>
> Agreed with MST that we should glue this to compat machines.
>
> --
> Cheers,
>
> David / dhildenb
>