[PATCH] powerpc/64s: use ibm,tlbiel-congruence-classes-(hash|radix) dt property
Nicholas Piggin
npiggin at gmail.com
Wed Apr 26 18:29:48 AEST 2017
On Mon, 24 Apr 2017 13:53:12 +0530
"Aneesh Kumar K.V" <aneesh.kumar at linux.vnet.ibm.com> wrote:
> Nicholas Piggin <npiggin at gmail.com> writes:
>
> > tlbiel instruction with IS!=0 on POWER7 and later Book3s CPUs invalidate
> > TLBs belonging to a specified congruence class. In order to operate on
> > the entire TLB, all congruence classes must be specified, requiring a
> > software loop.
> >
> > This dt property specifies the number of classes that must be operated
> > on. Use this to set tlbiel loop counts. If the property does not exist,
> > fall back to hard coded values based on the cpu table.
> >
> > Signed-off-by: Nicholas Piggin <npiggin at gmail.com>
> > return 0;
> .....
> .....
>
> > diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c
> > index d2f0afeae5a0..08ec2f431eff 100644
> > --- a/arch/powerpc/kernel/prom.c
> > +++ b/arch/powerpc/kernel/prom.c
> > @@ -236,8 +236,27 @@ static void __init init_mmu_slb_size(unsigned long node)
> > if (slb_size_ptr)
> > mmu_slb_size = be32_to_cpup(slb_size_ptr);
> > }
> > +static void __init init_mmu_tlb_sets_hash(unsigned long node)
> > +{
> > + const __be32 *ptr;
> > +
> > + ptr = of_get_flat_dt_prop(node, "ibm,tlbiel-congruence-classes-hash", NULL);
> > + if (ptr)
> > + cur_cpu_spec->tlb_sets_hash = be32_to_cpup(ptr);
> > +}
> > +
> > +static void __init init_mmu_tlb_sets_radix(unsigned long node)
> > +{
> > + const __be32 *ptr;
> > +
> > + ptr = of_get_flat_dt_prop(node, "ibm,tlbiel-congruence-classes-radix", NULL);
> > + if (ptr)
> > + cur_cpu_spec->tlb_sets_radix = be32_to_cpup(ptr);
> > +}
> > #else
> > #define init_mmu_slb_size(node) do { } while(0)
> > +#define init_mmu_hash_sets(node) do { } while(0)
> > +#define init_mmu_radix_sets(node) do { } while(0)
> > #endif
> >
> > static struct feature_property {
> > @@ -385,6 +404,8 @@ static int __init early_init_dt_scan_cpus(unsigned long node,
> > check_cpu_feature_properties(node);
> > check_cpu_pa_features(node);
> > init_mmu_slb_size(node);
> > + init_mmu_tlb_sets_hash(node);
> > + init_mmu_tlb_sets_radix(node);
> >
>
>
> I thought cpu features patch series had a generic mechanism to parse all
> these based on dt_cpu_feature_match_table[] ?
It could in theory. We could have a feature node for this set-wise
invalidation behaviour, and make a custom property of that feature
to give the number of sets to loop over.
At the moment Ben preferred each feature to be just a "binary" (present
or absent), with the accompanying metadata just being for the
compatibility bits. But this is a policy decision, and we may reconsider
it as we start adding extra cpu-features for future hardware.
For these numbers I think it's okay to add this way for now.
> > diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
> > index fadb75abfe37..2211cda5de90 100644
> > --- a/arch/powerpc/kvm/book3s_hv.c
> > +++ b/arch/powerpc/kvm/book3s_hv.c
> > @@ -3430,14 +3430,7 @@ static int kvmppc_core_init_vm_hv(struct kvm *kvm)
> > * Work out how many sets the TLB has, for the use of
> > * the TLB invalidation loop in book3s_hv_rmhandlers.S.
> > */
> > - if (kvm_is_radix(kvm))
> > - kvm->arch.tlb_sets = POWER9_TLB_SETS_RADIX; /* 128 */
> > - else if (cpu_has_feature(CPU_FTR_ARCH_300))
> > - kvm->arch.tlb_sets = POWER9_TLB_SETS_HASH; /* 256 */
> > - else if (cpu_has_feature(CPU_FTR_ARCH_207S))
> > - kvm->arch.tlb_sets = POWER8_TLB_SETS; /* 512 */
> > - else
> > - kvm->arch.tlb_sets = POWER7_TLB_SETS; /* 128 */
> > + kvm->arch.tlb_sets = cur_cpu_spec->tlb_sets;
>
>
> This should be based on guest mode right ? ie, we need to set
> kvm->arch.tlb_sets based on the mode kvm guest is running ?
You mean radix vs hash? Yes... Well, that's a reasonable assumption for
the behaviour of a CPU that supports guest mode != host mode, right? I'll
make the change.
> > /*
> > * Track that we now have a HV mode VM active. This blocks secondary
> > diff --git a/arch/powerpc/kvm/book3s_hv_ras.c b/arch/powerpc/kvm/book3s_hv_ras.c
> > index 7ef0993214f3..f62798ce304b 100644
> > --- a/arch/powerpc/kvm/book3s_hv_ras.c
> > +++ b/arch/powerpc/kvm/book3s_hv_ras.c
> > @@ -87,8 +87,7 @@ static long kvmppc_realmode_mc_power7(struct kvm_vcpu *vcpu)
> > DSISR_MC_SLB_PARITY | DSISR_MC_DERAT_MULTI);
> > }
> > if (dsisr & DSISR_MC_TLB_MULTI) {
> > - if (cur_cpu_spec && cur_cpu_spec->flush_tlb)
> > - cur_cpu_spec->flush_tlb(TLB_INVAL_SCOPE_LPID);
> > + machine_check_flush_tlb(TLB_INVAL_SCOPE_LPID);
> > dsisr &= ~DSISR_MC_TLB_MULTI;
> > }
> > /* Any other errors we don't understand? */
> > @@ -105,8 +104,7 @@ static long kvmppc_realmode_mc_power7(struct kvm_vcpu *vcpu)
> > reload_slb(vcpu);
> > break;
> > case SRR1_MC_IFETCH_TLBMULTI:
> > - if (cur_cpu_spec && cur_cpu_spec->flush_tlb)
> > - cur_cpu_spec->flush_tlb(TLB_INVAL_SCOPE_LPID);
> > + machine_check_flush_tlb(TLB_INVAL_SCOPE_LPID);
> > break;
> > default:
> > handled = 0;
> > diff --git a/arch/powerpc/mm/init_64.c b/arch/powerpc/mm/init_64.c
> > index ec84b31c6c86..a7c771170993 100644
> > --- a/arch/powerpc/mm/init_64.c
> > +++ b/arch/powerpc/mm/init_64.c
> > @@ -405,9 +405,15 @@ void __init mmu_early_init_devtree(void)
> > if (!(mfmsr() & MSR_HV))
> > early_check_vec5();
> >
> > - if (early_radix_enabled())
> > + if (early_radix_enabled()) {
> > + cur_cpu_spec->tlb_sets = cur_cpu_spec->tlb_sets_radix;
> > radix__early_init_devtree();
> > - else
> > + } else {
> > + cur_cpu_spec->tlb_sets = cur_cpu_spec->tlb_sets_hash;
> > hash__early_init_devtree();
> > + }
> > + /* This should not happen, but fall back to 1 set */
> > + if (!cur_cpu_spec->tlb_sets)
> > + cur_cpu_spec->tlb_sets = 1;
> > }
> > #endif /* CONFIG_PPC_STD_MMU_64 */
> > diff --git a/arch/powerpc/mm/tlb-radix.c b/arch/powerpc/mm/tlb-radix.c
> > index b68b5219cf45..76c8ed7549a7 100644
> > --- a/arch/powerpc/mm/tlb-radix.c
> > +++ b/arch/powerpc/mm/tlb-radix.c
> > @@ -38,15 +38,16 @@ static inline void __tlbiel_pid(unsigned long pid, int set,
> > : : "r"(rb), "i"(r), "i"(prs), "i"(ric), "r"(rs) : "memory");
> > }
> >
> > -/*
> > - * We use 128 set in radix mode and 256 set in hpt mode.
> > - */
> > static inline void _tlbiel_pid(unsigned long pid, unsigned long ric)
> > {
> > int set;
> >
> > asm volatile("ptesync": : :"memory");
> > - for (set = 0; set < POWER9_TLB_SETS_RADIX ; set++) {
> > + /*
> > + * tlbiel with IS != 0 operates on a specified congruence class,
> > + * requiring a loop to invalidate the entire TLB (see ISA).
> > + */
> > + for (set = 0; set < cur_cpu_spec->tlb_sets; set++) {
> > __tlbiel_pid(pid, set, ric);
> > }
> > asm volatile("ptesync": : :"memory");
> > --
> > 2.11.0
>
> This may need a rebase if mpe is going to take https://lists.ozlabs.org/pipermail/linuxppc-dev/2017-April/157130.html
Yeah shouldn't be much problem.
Thanks,
Nick
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