Re: [Qemu-devel] [PATCH] sparc32 machine specific maximums

[Robert Reif <reif@earthlink.net>]

Blue Swirl wrote:

>On 12/3/07, Robert Reif <reif@earthlink.net> wrote:
>  
>
>>This patch sets the maximum number of CPUs and memory to what is
>>supported by the actual hardware.
>>    
>>
>
>While it's not historically accurate to emulate a Sparcstation 5 with
>16 CPUs and 2 gigabytes of memory, it doesn't break anything to have
>this capability. We don't throttle the power of the CPU, speed of the
>network, serial or disk devices either, so they may be unrealistically
>fast. The timers are not accurate at all compared to CPU execution
>speed.
>
>Currently the memory on SS-5 machine is limited by the location of
>IOMMU and that the memory lies in one linear bank starting from zero.
>With more advanced banking and >4G patches, the entire physical
>address space could be filled with RAM.
>
>  
>
I would be surprised if an SMP kernel actually worked on a multi CPU SS5.
Currently OSs like solaris and bsd that actually use more than a minimal
amount of hardware don't work in QEMU.  That's because QEMUs
system emulation is both incomplete and inaccurate.  If you want to make 
a 16
CPU, 64 Gb machine, define a QEMU specific machine.  There are no real
32 bit sparc systems like that. I would like to see real sun openboot ROM
images work on realistic emulated hardware so QEMU could be used for
real OS development.