Re: [Qemu-devel] [Bug 1579327] Re: emulation of vexpress-a9 vexpress-a15 in multicore mode seems to be broken

[Peter Maydell <peter.maydell@linaro.org>]

On 9 May 2016 at 13:47, embedded0n3 <jainformatyka@interia.pl> wrote:
> Does -smp cores=4 means qemu is emulaing versatile espress a9 with 4
> cores ( this is how versatile express board is designed - i mean it's a
> board with 4 cores cotex a9 ) and qemu without -smp parameter emalates
> jus single core ( unicore )?

Yes.

> U-boot configuration file is created to run on physical  versatile a9
> board. And this was confirmed by Tom Rini (  the head custodian of Das
> U-boot project as I see on his stackoverflow page ) to run without
> problems on physical 4 core versatile express a9 board ( see
> stackoverflow disscussion link in 1st message of this bug report ):
>
> Here is citation of his comment:
>
>>I have recently gotten confirmation that the real HW does work on current mainline U-Boot,
>> but I can also replicate your failures. Interestingly, the real board is 4 cores,
>> and I can (with the kernelci.org Linux kernel / device tree) run with -smp cores=2
>> but 3 and 4 result in soft lockups once userland starts. – Tom Rini 2 days ago
>
> So he even had more erors as he get further in linux boot process ( I
> stopped tests so far on just loading u-boot and waiting few minutes if
> it will fail suddenly, what happend ). As I said errors were quiet
> random, and sometimes appeard just after more than minute of inactivity,
> other times almost instantly after boot ).

The next phase is that somebody needs to debug what the u-boot code is
doing that causes it to crash (this is largely working with the guest
code, not trying to debug QEMU itself).

thanks
-- PMM