Re: [Qemu-devel] [RESEND 1/2] kvmclock: use a light weight interface to update env->tsc.

[Li, Liang Z]

> This can be simplified a bit:
> 
> int kvm_get_tsc(CPUState *cs)
> {
>     X86CPU *cpu = X86_CPU(cs);
>     CPUX86State *env = &cpu->env;
>     struct {
>         struct kvm_msrs info;
>         struct kvm_msr_entry entries[1];
>     } msr_data;
>     int ret;
> 
>     if (env->tsc_valid) {
>         return 0;
>     }
> 
>     msr_data.info.nmsrs = 1;
>     msr_data.entries[0].index = MSR_IA32_TSC;
>     env->tsc_valid = !runstate_is_running();
> 
>     ret = kvm_vcpu_ioctl(CPU(cpu), KVM_GET_MSRS, &msr_data);
>     if (ret < 0) {
>         return ret;
>     }
> 
>     env->tsc = msr_data.entries[0].data;
>     return 0;
> }
> 
> >
> > +        CPU_FOREACH(cpu) {
> > +            ret = kvm_get_tsc(cpu);
> > +            if (ret < 0) {
> > +                fprintf(stderr, "KVM_GET_MSRS failed: %s\n", 
> > strerror(ret));
> > +                abort();
> > +                return;
> > +            }
> > +        }
> 
> 
> This should be run in the appropriate thread using run_on_cpu.  VCPU ioctls
> should only be invoked from the VCPU thread.  So you should introduce a new
> function kvm_synchronize_all_tsc() or something like that.
> 
> Otherwise, the idea behind the patches is fine.  Thanks!
> 
> Paolo

Thanks for your comments, I will send the v3.

Liang