Re: [Qemu-devel] Does QEMU support MIPS SMP2 malta board?

[Edgar E. Iglesias]

On Fri, Nov 15, 2013 at 05:48:03PM +0800, Nancy wrote:
> It works with -cpu 34Kf, but why cpuinfo display MIPS 34Kc?

I don't know, maybe Linux doesn't differentiate them? Or qemu has
the wrong prid for the 34Kf?


> I notes the smp based on kvm implement, but there do not have kvm
> implement under target-mips? how this smp implement? Is there any
> document record the QEMU MIPS smp internal?

The emulated (TCG) SMP support implements parts of the MIPS MT ASE.
On malta, -smp is a bit of a missuse, it controls the nr of VPEs and
-smp threads=x controls the nr of TCs.

IIRC the SMTC mechanisms are incomplete, both in the kernel and in
QEMU so for example -smp 2,threads=2 wont work.

Not sure what you mean with "based on KVM" but The TCG support for
MT was added independently and AFAIK before KVM mips was published.

Cheers,
Edgar


> 
> Does QEMU for MIPS target support FPU, SIMD instruction?
> 
> cat /proc/cpuinfo
> system type        : MIPS Malta
> machine            : Unknown
> processor        : 0
> cpu model        : MIPS 34Kc V0.0  FPU V0.0
> BogoMIPS        : 875.72
> wait instruction    : yes
> microsecond timers    : yes
> tlb_entries        : 16
> extra interrupt vector    : yes
> hardware watchpoint    : yes, count: 1, address/irw mask: [0x0ff8]
> isa            : mips1 mips2 mips32r1 mips32r2
> ASEs implemented    : mips16 dsp mt
> shadow register sets    : 16
> kscratch registers    : 0
> core            : 0
> VCED exceptions        : not available
> VCEI exceptions        : not available
> 
> processor        : 1
> cpu model        : MIPS 34Kc V0.0  FPU V0.0
> BogoMIPS        : 841.31
> wait instruction    : yes
> microsecond timers    : yes
> tlb_entries        : 16
> extra interrupt vector    : yes
> hardware watchpoint    : yes, count: 1, address/irw mask: [0x0ff8]
> isa            : mips1 mips2 mips32r1 mips32r2
> ASEs implemented    : mips16 dsp mt
> shadow register sets    : 16
> kscratch registers    : 0
> core            : 1
> VCED exceptions        : not available
> VCEI exceptions        : not available
> 
> On Fri, Nov 8, 2013 at 12:13 AM, Edgar E. Iglesias
> <address@hidden> wrote:
> > On Thu, Oct 31, 2013 at 11:47:12AM +0800, Nancy wrote:
> >> Hi,
> >>
> >> Does QEMU support MIPS smp 2 malta board?
> >>
> >> $ qemu-system-mipsel -M malta -kernel vmlinux -initrd  ramfs.cpio.gz \
> >> -append "console=ttyS0 root=/dev/ram0 maxcpus=2"  -nographic -s \
> >> -smp 2
> >>
> >
> > ....
> >
> >>
> >>
> >> There's no problem while I removing "-smp 2" option. (plus the kernel
> >> MIPS configure file " malta_defconfig" support smp 2 )
> >
> >
> > Hi,
> >
> > Yes it should work.
> > Can you please try again with -cpu 34Kf?
> >
> > Cheers,
> > Edgar
> 
> 
> 
> -- 
> Best Regards,
> Yu Rong Tan