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Re: [PATCH v4 5/5] target/riscv: Implement privilege mode filtering for
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From: |
Alistair Francis |
|
Subject: |
Re: [PATCH v4 5/5] target/riscv: Implement privilege mode filtering for cycle/instret |
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Date: |
Thu, 15 Feb 2024 14:45:06 +1000 |
On Tue, Jan 9, 2024 at 10:29 AM Atish Patra <atishp@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 <dbarboza@ventanamicro.com>
> Signed-off-by: Atish Patra <atishp@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];
> + /* 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;
I don't follow why we access different arrays depending if
icount_enabled(). Can we at least comment this?
Alistair
> + 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
>
>