On Sat, Sep 10, 2016 at 09:03:56AM +1000, Benjamin Herrenschmidt wrote:
> On Fri, 2016-09-09 at 18:44 +0530, Nikunj A Dadhania wrote:
> > +static inline void tlb_clear_flag(CPUState *cs)
> > +{
> > + PowerPCCPU *cpu = POWERPC_CPU(cs);
> > + CPUPPCState *env = &cpu->env;
> > +
> > + env->tlb_need_flush = 0;
> > +}
>
> What is the point of making this a separate function ?
>
> Also I'm not 100% certain about the correctness of clearing
> TLB_NEED_GLOBAL_FLUSH on the "other" guy.
>
> We could have the situation where:
>
> cpu 1: cpu 2:
> sets both ..
> isync (clears local flush) ..
> <insert new translation>
> .. set both
> .. ..
> .. ..
> ptesync (clears global flush) .. (both gets cleared)
>
> Now here, you can see that cpu2 never does a global flush and so the
> new translation inserted by cpu 1 is not cleared while architecturally
> it should be.
>
> That being said, I doubt the above scenario can happen in practice,
> but I think it's safer if you only clear the local bit on the "other"
> CPUs.
I'll wait for a respin addressing these comments.
Please also add a cover letter on the next version.
>
> > static inline void check_tlb_flush(CPUPPCState *env, uint32_t
> > global)
> > {
> > CPUState *cs = CPU(ppc_env_get_cpu(env));
> > @@ -161,6 +169,17 @@ static inline void check_tlb_flush(CPUPPCState
> > *env, uint32_t global)
> > tlb_flush(cs, 1);
> > env->tlb_need_flush &= ~TLB_NEED_LOCAL_FLUSH;
> > }
> > +
> > + if (global && (env->tlb_need_flush & TLB_NEED_GLOBAL_FLUSH)) {
> > + CPUState *other_cs;
> > + CPU_FOREACH(other_cs) {
> > + if (other_cs != cs) {
> > + tlb_clear_flag(other_cs);
> > + tlb_flush(other_cs, 1);
> > + }
> > + }
> > + env->tlb_need_flush &= ~TLB_NEED_GLOBAL_FLUSH;
> > + }
> > }
> > #else
>
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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