On Sun, Jan 21, 2024 at 9:04 PM Alistair Francis <alistai...@gmail.com> wrote:
>
> On Tue, Jan 9, 2024 at 10:29 AM Atish Patra <ati...@rivosinc.com> wrote:
> >
> > Privilege mode filtering can also be emulated for cycle/instret by
> > tracking host_ticks/icount during each privilege mode switch. This
> > patch implements that for both cycle/instret and mhpmcounters. The
> > first one requires Smcntrpmf while the other one requires Sscofpmf
> > to be enabled.
> >
> > The cycle/instret are still computed using host ticks when icount
> > is not enabled. Otherwise, they are computed using raw icount which
> > is more accurate in icount mode.
> >
> > Reviewed-by: Daniel Henrique Barboza <dbarb...@ventanamicro.com>
> > Signed-off-by: Atish Patra <ati...@rivosinc.com>
> > ---
> > target/riscv/cpu.h | 11 +++++
> > target/riscv/cpu_helper.c | 9 +++-
> > target/riscv/csr.c | 95 ++++++++++++++++++++++++++++++---------
> > target/riscv/pmu.c | 43 ++++++++++++++++++
> > target/riscv/pmu.h | 2 +
> > 5 files changed, 136 insertions(+), 24 deletions(-)
> >
> > diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
> > index 34617c4c4bab..40d10726155b 100644
> > --- a/target/riscv/cpu.h
> > +++ b/target/riscv/cpu.h
> > @@ -136,6 +136,15 @@ typedef struct PMUCTRState {
> > target_ulong irq_overflow_left;
> > } PMUCTRState;
> >
> > +typedef struct PMUFixedCtrState {
> > + /* Track cycle and icount for each privilege mode */
> > + uint64_t counter[4];
> > + uint64_t counter_prev[4];
>
> Are these two used?
>
Yes. That's where it tracks the current/previous value cycle/instret.
riscv_pmu_icount_update_priv/riscv_pmu_cycle_update_priv
The priv mode based filtering is enabled in riscv_pmu_ctr_get_fixed_counters_val
using "counter" afterwards.
Did I misunderstand your question ?
> Alistair
>
> > + /* Track cycle and icount for each privilege mode when V = 1*/
> > + uint64_t counter_virt[2];
> > + uint64_t counter_virt_prev[2];
> > +} PMUFixedCtrState;
> > +
> > struct CPUArchState {
> > target_ulong gpr[32];
> > target_ulong gprh[32]; /* 64 top bits of the 128-bit registers */
> > @@ -334,6 +343,8 @@ struct CPUArchState {
> > /* PMU event selector configured values for RV32 */
> > target_ulong mhpmeventh_val[RV_MAX_MHPMEVENTS];
> >
> > + PMUFixedCtrState pmu_fixed_ctrs[2];
> > +
> > target_ulong sscratch;
> > target_ulong mscratch;
> >
> > diff --git a/target/riscv/cpu_helper.c b/target/riscv/cpu_helper.c
> > index e7e23b34f455..3dddb1b433e8 100644
> > --- a/target/riscv/cpu_helper.c
> > +++ b/target/riscv/cpu_helper.c
> > @@ -715,8 +715,13 @@ void riscv_cpu_set_mode(CPURISCVState *env,
> > target_ulong newpriv)
> > {
> > g_assert(newpriv <= PRV_M && newpriv != PRV_RESERVED);
> >
> > - if (icount_enabled() && newpriv != env->priv) {
> > - riscv_itrigger_update_priv(env);
> > + if (newpriv != env->priv) {
> > + if (icount_enabled()) {
> > + riscv_itrigger_update_priv(env);
> > + riscv_pmu_icount_update_priv(env, newpriv);
> > + } else {
> > + riscv_pmu_cycle_update_priv(env, newpriv);
> > + }
> > }
> > /* tlb_flush is unnecessary as mode is contained in mmu_idx */
> > env->priv = newpriv;
> > diff --git a/target/riscv/csr.c b/target/riscv/csr.c
> > index 3bd4aa22374f..307d052021c5 100644
> > --- a/target/riscv/csr.c
> > +++ b/target/riscv/csr.c
> > @@ -782,32 +782,16 @@ static int write_vcsr(CPURISCVState *env, int csrno,
> > target_ulong val)
> > return RISCV_EXCP_NONE;
> > }
> >
> > +#if defined(CONFIG_USER_ONLY)
> > /* User Timers and Counters */
> > static target_ulong get_ticks(bool shift)
> > {
> > - int64_t val;
> > - target_ulong result;
> > -
> > -#if !defined(CONFIG_USER_ONLY)
> > - if (icount_enabled()) {
> > - val = icount_get();
> > - } else {
> > - val = cpu_get_host_ticks();
> > - }
> > -#else
> > - val = cpu_get_host_ticks();
> > -#endif
> > -
> > - if (shift) {
> > - result = val >> 32;
> > - } else {
> > - result = val;
> > - }
> > + int64_t val = cpu_get_host_ticks();
> > + target_ulong result = shift ? val >> 32 : val;
> >
> > return result;
> > }
> >
> > -#if defined(CONFIG_USER_ONLY)
> > static RISCVException read_time(CPURISCVState *env, int csrno,
> > target_ulong *val)
> > {
> > @@ -932,6 +916,70 @@ static int write_mhpmeventh(CPURISCVState *env, int
> > csrno, target_ulong val)
> > return RISCV_EXCP_NONE;
> > }
> >
> > +static target_ulong riscv_pmu_ctr_get_fixed_counters_val(CPURISCVState
> > *env,
> > + int counter_idx,
> > + bool upper_half)
> > +{
> > + uint64_t curr_val = 0;
> > + target_ulong result = 0;
> > + uint64_t *counter_arr = icount_enabled() ?
> > env->pmu_fixed_ctrs[1].counter :
> > + env->pmu_fixed_ctrs[0].counter;
> > + uint64_t *counter_arr_virt = icount_enabled() ?
> > + env->pmu_fixed_ctrs[1].counter_virt :
> > + env->pmu_fixed_ctrs[0].counter_virt;
> > + uint64_t cfg_val = 0;
> > +
> > + if (counter_idx == 0) {
> > + cfg_val = upper_half ? ((uint64_t)env->mcyclecfgh << 32) :
> > + env->mcyclecfg;
> > + } else if (counter_idx == 2) {
> > + cfg_val = upper_half ? ((uint64_t)env->minstretcfgh << 32) :
> > + env->minstretcfg;
> > + } else {
> > + cfg_val = upper_half ?
> > + ((uint64_t)env->mhpmeventh_val[counter_idx] << 32) :
> > + env->mhpmevent_val[counter_idx];
> > + }
> > +
> > + if (!cfg_val) {
> > + if (icount_enabled()) {
> > + curr_val = icount_get_raw();
> > + } else {
> > + curr_val = cpu_get_host_ticks();
> > + }
> > + goto done;
> > + }
> > +
> > + if (!(cfg_val & MCYCLECFG_BIT_MINH)) {
> > + curr_val += counter_arr[PRV_M];
> > + }
> > +
> > + if (!(cfg_val & MCYCLECFG_BIT_SINH)) {
> > + curr_val += counter_arr[PRV_S];
> > + }
> > +
> > + if (!(cfg_val & MCYCLECFG_BIT_UINH)) {
> > + curr_val += counter_arr[PRV_U];
> > + }
> > +
> > + if (!(cfg_val & MCYCLECFG_BIT_VSINH)) {
> > + curr_val += counter_arr_virt[PRV_S];
> > + }
> > +
> > + if (!(cfg_val & MCYCLECFG_BIT_VUINH)) {
> > + curr_val += counter_arr_virt[PRV_U];
> > + }
> > +
> > +done:
> > + if (riscv_cpu_mxl(env) == MXL_RV32) {
> > + result = upper_half ? curr_val >> 32 : curr_val;
> > + } else {
> > + result = curr_val;
> > + }
> > +
> > + return result;
> > +}
> > +
> > static int write_mhpmcounter(CPURISCVState *env, int csrno, target_ulong
> > val)
> > {
> > int ctr_idx = csrno - CSR_MCYCLE;
> > @@ -941,7 +989,8 @@ static int write_mhpmcounter(CPURISCVState *env, int
> > csrno, target_ulong val)
> > counter->mhpmcounter_val = val;
> > if (riscv_pmu_ctr_monitor_cycles(env, ctr_idx) ||
> > riscv_pmu_ctr_monitor_instructions(env, ctr_idx)) {
> > - counter->mhpmcounter_prev = get_ticks(false);
> > + counter->mhpmcounter_prev =
> > riscv_pmu_ctr_get_fixed_counters_val(env,
> > + ctr_idx,
> > false);
> > if (ctr_idx > 2) {
> > if (riscv_cpu_mxl(env) == MXL_RV32) {
> > mhpmctr_val = mhpmctr_val |
> > @@ -968,7 +1017,8 @@ static int write_mhpmcounterh(CPURISCVState *env, int
> > csrno, target_ulong val)
> > mhpmctr_val = mhpmctr_val | (mhpmctrh_val << 32);
> > if (riscv_pmu_ctr_monitor_cycles(env, ctr_idx) ||
> > riscv_pmu_ctr_monitor_instructions(env, ctr_idx)) {
> > - counter->mhpmcounterh_prev = get_ticks(true);
> > + counter->mhpmcounterh_prev =
> > riscv_pmu_ctr_get_fixed_counters_val(env,
> > + ctr_idx,
> > true);
> > if (ctr_idx > 2) {
> > riscv_pmu_setup_timer(env, mhpmctr_val, ctr_idx);
> > }
> > @@ -1009,7 +1059,8 @@ static RISCVException
> > riscv_pmu_read_ctr(CPURISCVState *env, target_ulong *val,
> > */
> > if (riscv_pmu_ctr_monitor_cycles(env, ctr_idx) ||
> > riscv_pmu_ctr_monitor_instructions(env, ctr_idx)) {
> > - *val = get_ticks(upper_half) - ctr_prev + ctr_val;
> > + *val = riscv_pmu_ctr_get_fixed_counters_val(env, ctr_idx,
> > upper_half) -
> > + ctr_prev + ctr_val;
> > } else {
> > *val = ctr_val;
> > }
> > diff --git a/target/riscv/pmu.c b/target/riscv/pmu.c
> > index 0e7d58b8a5c2..8b6cc4c6bb4d 100644
> > --- a/target/riscv/pmu.c
> > +++ b/target/riscv/pmu.c
> > @@ -19,6 +19,7 @@
> > #include "qemu/osdep.h"
> > #include "qemu/log.h"
> > #include "qemu/error-report.h"
> > +#include "qemu/timer.h"
> > #include "cpu.h"
> > #include "pmu.h"
> > #include "sysemu/cpu-timers.h"
> > @@ -176,6 +177,48 @@ static int riscv_pmu_incr_ctr_rv64(RISCVCPU *cpu,
> > uint32_t ctr_idx)
> > return 0;
> > }
> >
> > +void riscv_pmu_icount_update_priv(CPURISCVState *env, target_ulong newpriv)
> > +{
> > + uint64_t delta;
> > + uint64_t *counter_arr;
> > + uint64_t *counter_arr_prev;
> > + uint64_t current_icount = icount_get_raw();
> > +
> > + if (env->virt_enabled) {
> > + counter_arr = env->pmu_fixed_ctrs[1].counter_virt;
> > + counter_arr_prev = env->pmu_fixed_ctrs[1].counter_virt_prev;
> > + } else {
> > + counter_arr = env->pmu_fixed_ctrs[1].counter;
> > + counter_arr_prev = env->pmu_fixed_ctrs[1].counter_prev;
> > + }
> > +
> > + counter_arr_prev[newpriv] = current_icount;
> > + delta = current_icount - counter_arr_prev[env->priv];
> > +
> > + counter_arr[env->priv] += delta;
> > +}
> > +
> > +void riscv_pmu_cycle_update_priv(CPURISCVState *env, target_ulong newpriv)
> > +{
> > + uint64_t delta;
> > + uint64_t *counter_arr;
> > + uint64_t *counter_arr_prev;
> > + uint64_t current_host_ticks = cpu_get_host_ticks();
> > +
> > + if (env->virt_enabled) {
> > + counter_arr = env->pmu_fixed_ctrs[0].counter_virt;
> > + counter_arr_prev = env->pmu_fixed_ctrs[0].counter_virt_prev;
> > + } else {
> > + counter_arr = env->pmu_fixed_ctrs[0].counter;
> > + counter_arr_prev = env->pmu_fixed_ctrs[0].counter_prev;
> > + }
> > +
> > + counter_arr_prev[newpriv] = current_host_ticks;
> > + delta = current_host_ticks - counter_arr_prev[env->priv];
> > +
> > + counter_arr[env->priv] += delta;
> > +}
> > +
> > int riscv_pmu_incr_ctr(RISCVCPU *cpu, enum riscv_pmu_event_idx event_idx)
> > {
> > uint32_t ctr_idx;
> > diff --git a/target/riscv/pmu.h b/target/riscv/pmu.h
> > index 505fc850d38e..50de6031a730 100644
> > --- a/target/riscv/pmu.h
> > +++ b/target/riscv/pmu.h
> > @@ -31,3 +31,5 @@ int riscv_pmu_incr_ctr(RISCVCPU *cpu, enum
> > riscv_pmu_event_idx event_idx);
> > void riscv_pmu_generate_fdt_node(void *fdt, uint32_t cmask, char
> > *pmu_name);
> > int riscv_pmu_setup_timer(CPURISCVState *env, uint64_t value,
> > uint32_t ctr_idx);
> > +void riscv_pmu_icount_update_priv(CPURISCVState *env, target_ulong
> > newpriv);
> > +void riscv_pmu_cycle_update_priv(CPURISCVState *env, target_ulong newpriv);
> > --
> > 2.34.1
> >
> >
