Paul Mackerras <paulus@xxxxxxxxxx> writes:
> Although Linux doesn't use PURR and SPURR ((Scaled) Processor
> Utilization of Resources Register), other OSes depend on them.
> On POWER8 they count at a rate depending on whether the VCPU is
> idle or running, the activity of the VCPU, and the value in the
> RWMR (Region-Weighting Mode Register). Hardware expects the
> hypervisor to update the RWMR when a core is dispatched to reflect
> the number of online VCPUs in the vcore.
>
> This adds code to maintain a count in the vcore struct indicating
> how many VCPUs are online. In kvmppc_run_core we use that count
> to set the RWMR register on POWER8. If the core is split because
> of a static or dynamic micro-threading mode, we use the value for
> 8 threads. The RWMR value is not relevant when the host is
> executing because Linux does not use the PURR or SPURR register,
> so we don't bother saving and restoring the host value.
>
> For the sake of old userspace which does not set the KVM_REG_PPC_ONLINE
> register, we set online to 1 if it was 0 at the time of a KVM_RUN
> ioctl.
>
> Signed-off-by: Paul Mackerras <paulus@xxxxxxxxxx>
> ---
> arch/powerpc/include/asm/kvm_book3s.h | 1 +
> arch/powerpc/include/asm/reg.h | 1 +
> arch/powerpc/kvm/book3s_hv.c | 61 ++++++++++++++++++++++++++++++++++-
> 3 files changed, 62 insertions(+), 1 deletion(-)
>
> diff --git a/arch/powerpc/include/asm/kvm_book3s.h b/arch/powerpc/include/asm/kvm_book3s.h
> index e7377b7..c1f3a87 100644
> --- a/arch/powerpc/include/asm/kvm_book3s.h
> +++ b/arch/powerpc/include/asm/kvm_book3s.h
> @@ -104,6 +104,7 @@ struct kvmppc_vcore {
> ulong vtb; /* virtual timebase */
> ulong conferring_threads;
> unsigned int halt_poll_ns;
> + atomic_t online_count;
> };
>
> struct kvmppc_vcpu_book3s {
> diff --git a/arch/powerpc/include/asm/reg.h b/arch/powerpc/include/asm/reg.h
> index cb0f272..44b2be4 100644
> --- a/arch/powerpc/include/asm/reg.h
> +++ b/arch/powerpc/include/asm/reg.h
> @@ -365,6 +365,7 @@
> #define SPRN_PSSCR 0x357 /* Processor Stop Status and Control Register (ISA 3.0) */
> #define SPRN_PSSCR_PR 0x337 /* PSSCR ISA 3.0, privileged mode access */
> #define SPRN_PMCR 0x374 /* Power Management Control Register */
> +#define SPRN_RWMR 0x375 /* Region-Weighting Mode Register */
>
> /* HFSCR and FSCR bit numbers are the same */
> #define FSCR_SCV_LG 12 /* Enable System Call Vectored */
> diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
> index 04bd717..f61dd9e 100644
> --- a/arch/powerpc/kvm/book3s_hv.c
> +++ b/arch/powerpc/kvm/book3s_hv.c
> @@ -123,6 +123,32 @@ static bool no_mixing_hpt_and_radix;
> static void kvmppc_end_cede(struct kvm_vcpu *vcpu);
> static int kvmppc_hv_setup_htab_rma(struct kvm_vcpu *vcpu);
>
> +/*
> + * RWMR values for POWER8. These control the rate at which PURR
> + * and SPURR count and should be set according to the number of
> + * online threads in the vcore being run.
> + */
> +#define RWMR_RPA_P8_1THREAD 0x164520C62609AECA
> +#define RWMR_RPA_P8_2THREAD 0x7FFF2908450D8DA9
> +#define RWMR_RPA_P8_3THREAD 0x164520C62609AECA
> +#define RWMR_RPA_P8_4THREAD 0x199A421245058DA9
> +#define RWMR_RPA_P8_5THREAD 0x164520C62609AECA
> +#define RWMR_RPA_P8_6THREAD 0x164520C62609AECA
> +#define RWMR_RPA_P8_7THREAD 0x164520C62609AECA
> +#define RWMR_RPA_P8_8THREAD 0x164520C62609AECA
> +
> +static unsigned long p8_rwmr_values[MAX_SMT_THREADS + 1] = {
> + RWMR_RPA_P8_1THREAD,
> + RWMR_RPA_P8_1THREAD,
This has repeated twice here?
> + RWMR_RPA_P8_2THREAD,
> + RWMR_RPA_P8_3THREAD,
> + RWMR_RPA_P8_4THREAD,
> + RWMR_RPA_P8_5THREAD,
> + RWMR_RPA_P8_6THREAD,
> + RWMR_RPA_P8_7THREAD,
> + RWMR_RPA_P8_8THREAD,
> +};
> +
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