Re: [Qemu-devel] [PATCH] RFC: linux-user-i386: crash on cpuid

[Marc-André Lureau]

Hi

----- Original Message -----
> On Fri, Sep 16, 2016 at 06:41:32PM +0400, Marc-André Lureau wrote:
> > Running cpuid instructions with a simple run like:
> > i386-linux-user/qemu-i386 tests/tcg/sha1-i386
> > 
> > Results in the following assert:
> >  #0  0x00007ffff64246f5 in raise () from /lib64/libc.so.6
> >  #1  0x00007ffff64262fa in abort () from /lib64/libc.so.6
> >  #2  0x00007ffff7937ec5 in g_assertion_message () from
> >  /lib64/libglib-2.0.so.0
> >  #3  0x00007ffff7937f5a in g_assertion_message_expr () from
> >  /lib64/libglib-2.0.so.0
> >  #4  0x000055555561b54c in apicid_bitwidth_for_count (count=0) at
> >  /home/elmarco/src/qemu/include/hw/i386/topology.h:58
> >  #5  0x000055555561b58a in apicid_smt_width (nr_cores=0, nr_threads=0) at
> >  /home/elmarco/src/qemu/include/hw/i386/topology.h:67
> >  #6  0x000055555561b5c3 in apicid_core_offset (nr_cores=0, nr_threads=0) at
> >  /home/elmarco/src/qemu/include/hw/i386/topology.h:82
> >  #7  0x000055555561b5e3 in apicid_pkg_offset (nr_cores=0, nr_threads=0) at
> >  /home/elmarco/src/qemu/include/hw/i386/topology.h:89
> >  #8  0x000055555561dd86 in cpu_x86_cpuid (env=0x555557999550, index=4,
> >  count=3, eax=0x7fffffffcae8, ebx=0x7fffffffcaec, ecx=0x7fffffffcaf0,
> >  edx=0x7fffffffcaf4) at /home/elmarco/src/qemu/target-i386/cpu.c:2405
> >  #9  0x0000555555638e8e in helper_cpuid (env=0x555557999550) at
> >  /home/elmarco/src/qemu/target-i386/misc_helper.c:106
> >  #10 0x000055555599dc5e in static_code_gen_buffer ()
> >  #11 0x00005555555952f8 in cpu_tb_exec (cpu=0x5555579912d0,
> >  itb=0x7ffff4371ab0) at /home/elmarco/src/qemu/cpu-exec.c:166
> >  #12 0x0000555555595c8e in cpu_loop_exec_tb (cpu=0x5555579912d0,
> >  tb=0x7ffff4371ab0, last_tb=0x7fffffffd088, tb_exit=0x7fffffffd084,
> >  sc=0x7fffffffd0a0) at /home/elmarco/src/qemu/cpu-exec.c:517
> >  #13 0x0000555555595e50 in cpu_exec (cpu=0x5555579912d0) at
> >  /home/elmarco/src/qemu/cpu-exec.c:612
> >  #14 0x00005555555c065b in cpu_loop (env=0x555557999550) at
> >  /home/elmarco/src/qemu/linux-user/main.c:297
> >  #15 0x00005555555c25b2 in main (argc=2, argv=0x7fffffffd848,
> >  envp=0x7fffffffd860) at /home/elmarco/src/qemu/linux-user/main.c:4803
> > 
> > The fields are set in qemu_init_vcpu() with softmmu, but it's a stub
> > with linux-user.
> > 
> > Signed-off-by: Marc-André Lureau <address@hidden>
> > ---
> >  target-i386/cpu.c | 5 ++++-
> >  1 file changed, 4 insertions(+), 1 deletion(-)
> > 
> > diff --git a/target-i386/cpu.c b/target-i386/cpu.c
> > index 5a5299a..ce8f798 100644
> > --- a/target-i386/cpu.c
> > +++ b/target-i386/cpu.c
> > @@ -3097,7 +3097,10 @@ static void x86_cpu_realizefn(DeviceState *dev,
> > Error **errp)
> >  
> >      mce_init(cpu);
> >  
> > -#ifndef CONFIG_USER_ONLY
> > +#ifdef CONFIG_USER_ONLY
> > +    cs->nr_cores = smp_cores;
> > +    cs->nr_threads = smp_threads;
> > +#else
> 
> On CONFIG_USER_ONLY, smp_cores and smp_threads are defined as:
> 
>   /* *-user doesn't have configurable SMP topology */
>   #define smp_cores   1
>   #define smp_threads 1
> 
> It sounds simpler to just set nr_cores and nr_threads to 1 by
> default in cpu_common_initfn(). (Preferably with a comment noting
> that the default value is changed by qemu_init_vcpu() for
> softmmu).

Ok, I'll resend a patch

thanks