Re: [PATCH v8 3/6] KVM: PPC: Book3S HV: Add support for H_RPT_INVALIDATE

[David Gibson <david@gibson.dropbear.id.au>]

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On Tue, Jul 06, 2021 at 10:56:32AM +0530, Bharata B Rao wrote:
> On Mon, Jul 05, 2021 at 02:42:33PM +1000, David Gibson wrote:
> > On Mon, Jun 21, 2021 at 02:20:00PM +0530, Bharata B Rao wrote:
> > > diff --git a/arch/powerpc/include/asm/mmu_context.h b/arch/powerpc/include/asm/mmu_context.h
> > > index 4bc45d3ed8b0..b44f291fc909 100644
> > > --- a/arch/powerpc/include/asm/mmu_context.h
> > > +++ b/arch/powerpc/include/asm/mmu_context.h
> > > @@ -124,8 +124,17 @@ static inline bool need_extra_context(struct mm_struct *mm, unsigned long ea)
> > >  
> > >  #if defined(CONFIG_KVM_BOOK3S_HV_POSSIBLE) && defined(CONFIG_PPC_RADIX_MMU)
> > >  extern void radix_kvm_prefetch_workaround(struct mm_struct *mm);
> > > +void do_h_rpt_invalidate_prt(unsigned long pid, unsigned long lpid,
> > > +			     unsigned long type, unsigned long pg_sizes,
> > > +			     unsigned long start, unsigned long end);
> > >  #else
> > >  static inline void radix_kvm_prefetch_workaround(struct mm_struct *mm) { }
> > > +static inline void do_h_rpt_invalidate_prt(unsigned long pid,
> > > +					   unsigned long lpid,
> > > +					   unsigned long type,
> > > +					   unsigned long pg_sizes,
> > > +					   unsigned long start,
> > > +					   unsigned long end) { }
> > 
> > Since the only plausible caller is in KVM HV code, why do you need the
> > #else clause.
> 
> The call to the above routine is prevented for non-radix guests
> in KVM HV code at runtime using kvm_is_radix() check and not by
> CONFIG_PPC_RADIX_MMU. Hence the #else version would be needed.

kvm_is_radix() should evaluate to false at compile time if
!defined(CONFIG_PPC_RADIX_MMU), in which case, no you shouldn't need
the else version.

-- 
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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