Re: [Qemu-discuss] Running dual-core ARM Cortexa9

[Ilya Katsnelson]

Thanks, Peter.
My final HW platform is an ALTERA's Arria10 FPGA which has 2 ARM cores. So it 
would be useful to simulate them correctly. But I'll take one core if that's 
the only thing available.
However, QEMU has multicore parameters. If the only thing they do is just 
reduce performance, why support them?
So is there any way to simulate dual ARMs on QEMU?

-Ilya.


________________________________________
From: Peter Maydell <address@hidden>
Sent: Tuesday, December 22, 2015 4:21 AM
To: Ilya Katsnelson
Cc: address@hidden
Subject: Re: [Qemu-discuss] Running dual-core ARM Cortexa9

On 21 December 2015 at 18:40, Ilya Katsnelson <address@hidden> wrote:
> Does anyone have experience running ARM Dual-core (in particular) Cortexa9
> simulation? Can you share the exact parameters that should be used?

Why do you want to run dual-core? At the moment it will just
give worse performance than running a single core TCG guest
(there is extra overhead).

> qemu-system-arm -kernel zImage-vcm4-try.bin -net nic,model=virtio -net
> tap,vlan=0,ifname=tap0,script=no,downscript=no -M versatilepb -drive
> file=core-image-minimal-vcm4-try-20151220011520.rootfs.ext4,if=virtio,format=raw
> -no-reboot -show-cursor -usb -usbdevice wacom-tablet -no-reboot -nographic
> -serial mon:stdio -append 'console=ttyS0' -m 128 -serial null --append
> "root=/dev/vda rw console=ttyAMA0,115200 console=tty
> ip=192.168.7.2::192.168.7.1:255.255.255.0 mem=128M highres=off
> rootfstype=ext4 "
>
>
> However, it uses versatilepb as the machine and it only supports one core.
>
> I've tried using different machine parameter - "-M vexpress-a9 -cpu
> cortex-a9". But then QEMu was complaining that the network driver was
> incorrect, then USB driver, then storage driver.

If you want to run on a different emulated board you will need
to have the correct kernel and command lines for that different
board; you can't in general just change the machine parameter
(this will have about the same effect as putting a versatilepb
kernel onto real vexpress-a9 hardware, ie the guest will crash
on startup.)

There is no PCI support on vexpress-a9, which is why your
command line arguments won't work (they're creating emulated
PCI USB, network, etc devices).

thanks
-- PMM