Re: [Qemu-devel] [target-mips] How to use smp?

[Edgar E. Iglesias]

On Mon, Jun 24, 2013 at 03:52:52PM +0800, Dongxue Zhang wrote:
> Hello everybody, i want to use mips target with smp support.  When use 
> command without smp, then the log stopped at "kernel panic", when -
> smp 2
> added, it stoppted at "NR_IRQS:256".
> 
> I use the git qemu at 576156ffed72ab4feb0b752979db86ff8759a2a1
> qemu configed with "./configure --target-list=mips64el-softmmu"
> qemu run command "qemu-system-mips64el -kernel linux-3.8.2/vmlinux -
> nographic -smp 2"
> 
> The linux kernel used release version.

I'm not up to date with the MIPS SMP terminology and I might remember
wrongly but:

AFAIK the SMP support is only functional for certain 32bit MIPS cores.
And it's not full SMP support, the modelled parts are actually a subset of
the MT parts with multiple VPEs. It's also possible to have multiple
TCs per VPE IIRC but linux doesn't handle that very well.

I've previously succesfully run SMP malta kernels but the support was
developed towards an AXIS camera board. The GIC was never upstreamed as I
never got confirmation wether it was legally OK. MALTA doesn't need it
though, or at least it didnt at the time as the IPIs can be distributed
directly between VPEs on the same CPU group.

Cheers,
Edgar


> 
> 
> qemu-system-mips64el -kernel linux-3.8.2/vmlinux -nographic -smp 2 
> QEMU 1.5.50 monitor - type 'help' for more information
> (qemu) 
> Linux version 3.8.2 (address@hidden) (gcc version 4.7.2 (GCC) ) #1 SMP Mon 
> Jun 24
> 15:35:20 CST 2013
> Config serial console: console=ttyS0,38400n8r
> bootconsole [early0] enabled
> CPU revision is: 000182a0 (MIPS 20Kc)
> FPU revision is: 000f8200
> Checking for the multiply/shift bug... no.
> Checking for the daddiu bug... no.
> Determined physical RAM map:
>  memory: 0000000000001000 @ 0000000000000000 (reserved)
>  memory: 00000000000ef000 @ 0000000000001000 (ROM data)
>  memory: 0000000000be1000 @ 00000000000f0000 (reserved)
>  memory: 000000000732f000 @ 0000000000cd1000 (usable)
> Wasting 183736 bytes for tracking 3281 unused pages
> Zone ranges:
>   DMA      [mem 0x00000000-0x00ffffff]
>   Normal   [mem 0x01000000-0x07ffffff]
> Movable zone start for each node
> Early memory node ranges
>   node   0: [mem 0x00000000-0x07ffffff]
> Primary instruction cache 32kB, VIVT, 4-way, linesize 32 bytes.
> Primary data cache 32kB, 4-way, PIPT, no aliases, linesize 32 bytes
> PERCPU: Embedded 10 pages/cpu @98000000011c3000 s10816 r8192 d21952 u40960
> Built 1 zonelists in Zone order, mobility grouping on.  Total pages: 32320
> Kernel command line:  console=ttyS0,38400n8r
> PID hash table entries: 512 (order: 0, 4096 bytes)
> Dentry cache hash table entries: 16384 (order: 5, 131072 bytes)
> Inode-cache hash table entries: 8192 (order: 4, 65536 bytes)
> __ex_table already sorted, skipping sort
> Enable cache parity protection for MIPS 20KC/25KF CPUs.
> Memory: 115900k/117948k available (8466k kernel code, 2048k reserved, 3014k
> data, 356k init, 0k highmem)
> Hierarchical RCU implementation.
>         CONFIG_RCU_FANOUT set to non-default value of 32
>         RCU restricting CPUs from NR_CPUS=2 to nr_cpu_ids=1.
> NR_IRQS:256
> 
> 
> Is there anyone have ideas to solve this problem?