On Tue, Feb 26, 2019 at 02:05:29PM +1100, Suraj Jitindar Singh wrote: > Prior to POWER9 the decrementer was a 32-bit register which decremented > with each tick of the timebase. From POWER9 onwards the decrementer can > be set to operate in a mode called large decrementer where it acts as a > n-bit decrementing register which is visible as a 64-bit register, that > is the value of the decrementer is sign extended to 64 bits (where n is > implementation dependant). > > The mode in which the decrementer operates is controlled by the LPCR_LD > bit in the logical paritition control register (LPCR). > > >From POWER9 onwards the HDEC (hypervisor decrementer) was enlarged to > h-bits, also sign extended to 64 bits (where h is implementation > dependant). Note this isn't configurable and is always enabled. > > For TCG we allow the user to configure a custom large decrementer size, > so long as it's at least 32 and less than the size of the HDEC (the > restrictions imposed by the ISA). > > Signed-off-by: Suraj Jitindar Singh > Signed-off-by: Cédric Le Goater > --- > hw/ppc/ppc.c | 78 ++++++++++++++++++++++++++++------------- > hw/ppc/spapr.c | 8 +++++ > hw/ppc/spapr_caps.c | 38 +++++++++++++++++++- > target/ppc/cpu-qom.h | 1 + > target/ppc/cpu.h | 11 +++--- > target/ppc/mmu-hash64.c | 2 +- > target/ppc/translate.c | 2 +- > target/ppc/translate_init.inc.c | 1 + > 8 files changed, 109 insertions(+), 32 deletions(-) > > diff --git a/hw/ppc/ppc.c b/hw/ppc/ppc.c > index d1e3d4cd20..853afeed6a 100644 > --- a/hw/ppc/ppc.c > +++ b/hw/ppc/ppc.c > @@ -744,10 +744,10 @@ bool ppc_decr_clear_on_delivery(CPUPPCState *env) > return ((tb_env->flags & flags) == PPC_DECR_UNDERFLOW_TRIGGERED); > } > > -static inline uint32_t _cpu_ppc_load_decr(CPUPPCState *env, uint64_t next) > +static inline uint64_t _cpu_ppc_load_decr(CPUPPCState *env, uint64_t next) Hrm. Given how we use this - and how muldiv64 works, wouldn't it make more sense to have it return int64_t (i.e. signed). > { > ppc_tb_t *tb_env = env->tb_env; > - uint32_t decr; > + uint64_t decr; > int64_t diff; > > diff = next - qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL); > @@ -758,27 +758,42 @@ static inline uint32_t _cpu_ppc_load_decr(CPUPPCState *env, uint64_t next) > } else { > decr = -muldiv64(-diff, tb_env->decr_freq, NANOSECONDS_PER_SECOND); > } > - LOG_TB("%s: %08" PRIx32 "\n", __func__, decr); > + LOG_TB("%s: %016" PRIx64 "\n", __func__, decr); > > return decr; > } > > -uint32_t cpu_ppc_load_decr (CPUPPCState *env) > +target_ulong cpu_ppc_load_decr (CPUPPCState *env) > { > ppc_tb_t *tb_env = env->tb_env; > + uint64_t decr; > > if (kvm_enabled()) { > return env->spr[SPR_DECR]; > } > > - return _cpu_ppc_load_decr(env, tb_env->decr_next); > + decr = _cpu_ppc_load_decr(env, tb_env->decr_next); > + > + /* > + * If large decrementer is enabled then the decrementer is signed extened > + * to 64 bits, otherwise it is a 32 bit value. > + */ > + if (env->spr[SPR_LPCR] & LPCR_LD) > + return decr; > + return (uint32_t) decr; > } > > -uint32_t cpu_ppc_load_hdecr (CPUPPCState *env) > +target_ulong cpu_ppc_load_hdecr (CPUPPCState *env) > { > ppc_tb_t *tb_env = env->tb_env; > + uint64_t decr; > > - return _cpu_ppc_load_decr(env, tb_env->hdecr_next); > + decr = _cpu_ppc_load_decr(env, tb_env->hdecr_next); > + > + /* If POWER9 or later then hdecr is sign extended to 64 bits otherwise 32 */ > + if (env->mmu_model & POWERPC_MMU_3_00) You already have a pcc->hdecr_bits. Wouldn't it make more sense to check against that than the cpu model directly? > + return decr; > + return (uint32_t) decr; > } > > uint64_t cpu_ppc_load_purr (CPUPPCState *env) > @@ -832,13 +847,21 @@ static void __cpu_ppc_store_decr(PowerPCCPU *cpu, uint64_t *nextp, > QEMUTimer *timer, > void (*raise_excp)(void *), > void (*lower_excp)(PowerPCCPU *), > - uint32_t decr, uint32_t value) > + target_ulong decr, target_ulong value, > + int nr_bits) > { > CPUPPCState *env = &cpu->env; > ppc_tb_t *tb_env = env->tb_env; > uint64_t now, next; > + bool negative; > + > + /* Truncate value to decr_width and sign extend for simplicity */ > + value &= ((1ULL << nr_bits) - 1); > + negative = !!(value & (1ULL << (nr_bits - 1))); Could you simplify this by just using negative = (int64_t)decr < 0; before you mask? Or would that be wrong in some edge case or other? > + if (negative) > + value |= (0xFFFFFFFFULL << nr_bits); > > - LOG_TB("%s: %08" PRIx32 " => %08" PRIx32 "\n", __func__, > + LOG_TB("%s: " TARGET_FMT_lx " => " TARGET_FMT_lx "\n", __func__, > decr, value); > > if (kvm_enabled()) { > @@ -860,15 +883,15 @@ static void __cpu_ppc_store_decr(PowerPCCPU *cpu, uint64_t *nextp, > * an edge interrupt, so raise it here too. > */ > if ((value < 3) || > - ((tb_env->flags & PPC_DECR_UNDERFLOW_LEVEL) && (value & 0x80000000)) || > - ((tb_env->flags & PPC_DECR_UNDERFLOW_TRIGGERED) && (value & 0x80000000) > - && !(decr & 0x80000000))) { > + ((tb_env->flags & PPC_DECR_UNDERFLOW_LEVEL) && negative) || > + ((tb_env->flags & PPC_DECR_UNDERFLOW_TRIGGERED) && negative > + && !(decr & (1ULL << (nr_bits - 1))))) { > (*raise_excp)(cpu); > return; > } > > /* On MSB level based systems a 0 for the MSB stops interrupt delivery */ > - if (!(value & 0x80000000) && (tb_env->flags & PPC_DECR_UNDERFLOW_LEVEL)) { > + if (!negative && (tb_env->flags & PPC_DECR_UNDERFLOW_LEVEL)) { > (*lower_excp)(cpu); > } > > @@ -881,21 +904,24 @@ static void __cpu_ppc_store_decr(PowerPCCPU *cpu, uint64_t *nextp, > timer_mod(timer, next); > } > > -static inline void _cpu_ppc_store_decr(PowerPCCPU *cpu, uint32_t decr, > - uint32_t value) > +static inline void _cpu_ppc_store_decr(PowerPCCPU *cpu, target_ulong decr, > + target_ulong value, int nr_bits) > { > ppc_tb_t *tb_env = cpu->env.tb_env; > > __cpu_ppc_store_decr(cpu, &tb_env->decr_next, tb_env->decr_timer, > tb_env->decr_timer->cb, &cpu_ppc_decr_lower, decr, > - value); > + value, nr_bits); > } > > -void cpu_ppc_store_decr (CPUPPCState *env, uint32_t value) > +void cpu_ppc_store_decr (CPUPPCState *env, target_ulong value) > { > PowerPCCPU *cpu = ppc_env_get_cpu(env); > + int nr_bits = 32; > + if ((env->spr[SPR_LPCR] & LPCR_LD) && (env->large_decr_bits > 32)) > + nr_bits = env->large_decr_bits; This would be simpler if you initialized large_decr_bits to 32 on cpus that don't have large decr, wouldn't it? > > - _cpu_ppc_store_decr(cpu, cpu_ppc_load_decr(env), value); > + _cpu_ppc_store_decr(cpu, cpu_ppc_load_decr(env), value, nr_bits); > } > > static void cpu_ppc_decr_cb(void *opaque) > @@ -905,23 +931,25 @@ static void cpu_ppc_decr_cb(void *opaque) > cpu_ppc_decr_excp(cpu); > } > > -static inline void _cpu_ppc_store_hdecr(PowerPCCPU *cpu, uint32_t hdecr, > - uint32_t value) > +static inline void _cpu_ppc_store_hdecr(PowerPCCPU *cpu, target_ulong hdecr, > + target_ulong value, int nr_bits) > { > ppc_tb_t *tb_env = cpu->env.tb_env; > > if (tb_env->hdecr_timer != NULL) { > __cpu_ppc_store_decr(cpu, &tb_env->hdecr_next, tb_env->hdecr_timer, > tb_env->hdecr_timer->cb, &cpu_ppc_hdecr_lower, > - hdecr, value); > + hdecr, value, nr_bits); > } > } > > -void cpu_ppc_store_hdecr (CPUPPCState *env, uint32_t value) > +void cpu_ppc_store_hdecr (CPUPPCState *env, target_ulong value) > { > PowerPCCPU *cpu = ppc_env_get_cpu(env); > + PowerPCCPUClass *pcc = POWERPC_CPU_GET_CLASS(cpu); > + int nr_bits = (pcc->hdecr_bits > 32) ? pcc->hdecr_bits : 32; Similarly with hdecr_bits. > - _cpu_ppc_store_hdecr(cpu, cpu_ppc_load_hdecr(env), value); > + _cpu_ppc_store_hdecr(cpu, cpu_ppc_load_hdecr(env), value, nr_bits); > } > > static void cpu_ppc_hdecr_cb(void *opaque) > @@ -951,8 +979,8 @@ static void cpu_ppc_set_tb_clk (void *opaque, uint32_t freq) > * if a decrementer exception is pending when it enables msr_ee at startup, > * it's not ready to handle it... > */ > - _cpu_ppc_store_decr(cpu, 0xFFFFFFFF, 0xFFFFFFFF); > - _cpu_ppc_store_hdecr(cpu, 0xFFFFFFFF, 0xFFFFFFFF); > + _cpu_ppc_store_decr(cpu, 0xFFFFFFFF, 0xFFFFFFFF, 32); > + _cpu_ppc_store_hdecr(cpu, 0xFFFFFFFF, 0xFFFFFFFF, 32); > cpu_ppc_store_purr(cpu, 0x0000000000000000ULL); > } > > diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c > index acf62a2b9f..966bc74e68 100644 > --- a/hw/ppc/spapr.c > +++ b/hw/ppc/spapr.c > @@ -557,6 +557,14 @@ static void spapr_populate_cpu_dt(CPUState *cs, void *fdt, int offset, > pcc->radix_page_info->count * > sizeof(radix_AP_encodings[0])))); > } > + > + /* > + * We set this property to let the guest know that it can use the large > + * decrementer and its width in bits. > + */ > + if (env->large_decr_bits) > + _FDT((fdt_setprop_u32(fdt, offset, "ibm,dec-bits", > + env->large_decr_bits))); > } > > static void spapr_populate_cpus_dt_node(void *fdt, sPAPRMachineState *spapr) > diff --git a/hw/ppc/spapr_caps.c b/hw/ppc/spapr_caps.c > index 1545a02729..44542fdbb2 100644 > --- a/hw/ppc/spapr_caps.c > +++ b/hw/ppc/spapr_caps.c > @@ -421,8 +421,43 @@ static void cap_nested_kvm_hv_apply(sPAPRMachineState *spapr, > static void cap_large_decr_apply(sPAPRMachineState *spapr, > uint8_t val, Error **errp) > { > - if (val) > + PowerPCCPU *cpu = POWERPC_CPU(first_cpu); > + PowerPCCPUClass *pcc = POWERPC_CPU_GET_CLASS(cpu); > + > + if (!val) > + return; /* Disabled by default */ > + > + if (tcg_enabled()) { > + if (!ppc_check_compat(cpu, CPU_POWERPC_LOGICAL_3_00, 0, > + spapr->max_compat_pvr)) { IIUC this is strictly redundant with the check against hdecr_bits, yes, but will result in a more helpful error message. Is that right? > + error_setg(errp, > + "Large decrementer only supported on POWER9, try -cpu POWER9"); > + return; > + } > + if ((val < 32) || (val > pcc->hdecr_bits)) { > + error_setg(errp, > + "Large decrementer size unsupported, try -cap-large-decr=%d", > + pcc->hdecr_bits); > + return; > + } > + } else { > error_setg(errp, "No large decrementer support, try cap-large-decr=0"); > + } > +} > + > +static void cap_large_decr_cpu_apply(sPAPRMachineState *spapr, > + PowerPCCPU *cpu, > + uint8_t val, Error **errp) > +{ > + CPUPPCState *env = &cpu->env; > + target_ulong lpcr = env->spr[SPR_LPCR]; > + > + if (val) > + lpcr |= LPCR_LD; > + else > + lpcr &= ~LPCR_LD; > + ppc_store_lpcr(cpu, lpcr); > + env->large_decr_bits = val; > } > > sPAPRCapabilityInfo capability_table[SPAPR_CAP_NUM] = { > @@ -511,6 +546,7 @@ sPAPRCapabilityInfo capability_table[SPAPR_CAP_NUM] = { > .set = spapr_cap_set_uint8, > .type = "int", > .apply = cap_large_decr_apply, > + .cpu_apply = cap_large_decr_cpu_apply, > }, > }; > > diff --git a/target/ppc/cpu-qom.h b/target/ppc/cpu-qom.h > index ae51fe754e..cced705e30 100644 > --- a/target/ppc/cpu-qom.h > +++ b/target/ppc/cpu-qom.h > @@ -190,6 +190,7 @@ typedef struct PowerPCCPUClass { > #endif > const PPCHash64Options *hash64_opts; > struct ppc_radix_page_info *radix_page_info; > + uint32_t hdecr_bits; > void (*init_proc)(CPUPPCState *env); > int (*check_pow)(CPUPPCState *env); > int (*handle_mmu_fault)(PowerPCCPU *cpu, vaddr eaddr, int rwx, int mmu_idx); > diff --git a/target/ppc/cpu.h b/target/ppc/cpu.h > index 26604ddf98..8da333e9da 100644 > --- a/target/ppc/cpu.h > +++ b/target/ppc/cpu.h > @@ -1171,6 +1171,9 @@ struct CPUPPCState { > uint32_t tm_vscr; > uint64_t tm_dscr; > uint64_t tm_tar; > + > + /* Large Decrementer */ > + int large_decr_bits; > }; > > #define SET_FIT_PERIOD(a_, b_, c_, d_) \ > @@ -1321,10 +1324,10 @@ uint32_t cpu_ppc_load_atbu (CPUPPCState *env); > void cpu_ppc_store_atbl (CPUPPCState *env, uint32_t value); > void cpu_ppc_store_atbu (CPUPPCState *env, uint32_t value); > bool ppc_decr_clear_on_delivery(CPUPPCState *env); > -uint32_t cpu_ppc_load_decr (CPUPPCState *env); > -void cpu_ppc_store_decr (CPUPPCState *env, uint32_t value); > -uint32_t cpu_ppc_load_hdecr (CPUPPCState *env); > -void cpu_ppc_store_hdecr (CPUPPCState *env, uint32_t value); > +target_ulong cpu_ppc_load_decr (CPUPPCState *env); > +void cpu_ppc_store_decr (CPUPPCState *env, target_ulong value); > +target_ulong cpu_ppc_load_hdecr (CPUPPCState *env); > +void cpu_ppc_store_hdecr (CPUPPCState *env, target_ulong value); > uint64_t cpu_ppc_load_purr (CPUPPCState *env); > uint32_t cpu_ppc601_load_rtcl (CPUPPCState *env); > uint32_t cpu_ppc601_load_rtcu (CPUPPCState *env); > diff --git a/target/ppc/mmu-hash64.c b/target/ppc/mmu-hash64.c > index c431303eff..a2b1ec5040 100644 > --- a/target/ppc/mmu-hash64.c > +++ b/target/ppc/mmu-hash64.c > @@ -1109,7 +1109,7 @@ void ppc_store_lpcr(PowerPCCPU *cpu, target_ulong val) > case POWERPC_MMU_3_00: /* P9 */ > lpcr = val & (LPCR_VPM1 | LPCR_ISL | LPCR_KBV | LPCR_DPFD | > (LPCR_PECE_U_MASK & LPCR_HVEE) | LPCR_ILE | LPCR_AIL | > - LPCR_UPRT | LPCR_EVIRT | LPCR_ONL | LPCR_HR | > + LPCR_UPRT | LPCR_EVIRT | LPCR_ONL | LPCR_HR | LPCR_LD | > (LPCR_PECE_L_MASK & (LPCR_PDEE | LPCR_HDEE | LPCR_EEE | > LPCR_DEE | LPCR_OEE)) | LPCR_MER | LPCR_GTSE | LPCR_TC | > LPCR_HEIC | LPCR_LPES0 | LPCR_HVICE | LPCR_HDICE); > diff --git a/target/ppc/translate.c b/target/ppc/translate.c > index 819221f246..b156be4d98 100644 > --- a/target/ppc/translate.c > +++ b/target/ppc/translate.c > @@ -7417,7 +7417,7 @@ void ppc_cpu_dump_state(CPUState *cs, FILE *f, fprintf_function cpu_fprintf, > #if !defined(NO_TIMER_DUMP) > cpu_fprintf(f, "TB %08" PRIu32 " %08" PRIu64 > #if !defined(CONFIG_USER_ONLY) > - " DECR %08" PRIu32 > + " DECR " TARGET_FMT_lu > #endif > "\n", > cpu_ppc_load_tbu(env), cpu_ppc_load_tbl(env) > diff --git a/target/ppc/translate_init.inc.c b/target/ppc/translate_init.inc.c > index 58542c0fe0..4e0bf1f47a 100644 > --- a/target/ppc/translate_init.inc.c > +++ b/target/ppc/translate_init.inc.c > @@ -8926,6 +8926,7 @@ POWERPC_FAMILY(POWER9)(ObjectClass *oc, void *data) > /* segment page size remain the same */ > pcc->hash64_opts = &ppc_hash64_opts_POWER7; > pcc->radix_page_info = &POWER9_radix_page_info; > + pcc->hdecr_bits = 56; > #endif > pcc->excp_model = POWERPC_EXCP_POWER9; > pcc->bus_model = PPC_FLAGS_INPUT_POWER9; -- 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