Re: [Qemu-devel] [PATCH] Add minimal Vexpress Cortex A15 support

[Peter Maydell]

On 6 December 2011 12:28, Avi Kivity <address@hidden> wrote:
> On 12/01/2011 03:37 AM, address@hidden wrote:
>> +    /* ??? Hack to map an additional page of ram for the secondary CPU
>> +       startup code.  I guess this works on real hardware because the
>> +       BootROM happens to be in ROM/flash or in memory that isn't clobbered
>> +       until after Linux boots the secondary CPUs.  */
>> +    ram_offset = qemu_ram_alloc(NULL, "vexpress.hack", 0x1000);
>> +    cpu_register_physical_memory(SMP_BOOT_ADDR, 0x1000,
>> +                                 ram_offset | IO_MEM_RAM);

> It would be better to unhack this; short-term hacks tend to remain in
> the long term, and even after they're fixed we keep them for backwards
> compatibility.

Do you have a better suggestion in this case? We've had the same
code in the realview board since 2007 when ARM SMP support was first
added...

There's no particular back-compat implication here as far as I know:
the location of the secondary CPU holding pen code is irrelevant to
the actual guest being run. (On a real system it will be somewhere
inside the boot ROM.)

-- PMM