On Thu, Mar 20, 2025 at 5:24 AM Jim Shu <jim....@sifive.com> wrote:
>
> Updating STCE will enable/disable SSTC in S-mode or/and VS-mode, so we
> also need to update S/VS-mode Timer and S/VSTIP bits in $mip CSR.
>
> Signed-off-by: Jim Shu <jim....@sifive.com>
> ---
> target/riscv/csr.c | 44 ++++++++++++++++++++++++++++++++
> target/riscv/time_helper.c | 51 ++++++++++++++++++++++++++++++++++++++
> target/riscv/time_helper.h | 1 +
> 3 files changed, 96 insertions(+)
>
> diff --git a/target/riscv/csr.c b/target/riscv/csr.c
> index ba026dfc8e..c954e49cae 100644
> --- a/target/riscv/csr.c
> +++ b/target/riscv/csr.c
> @@ -3156,6 +3156,7 @@ static RISCVException write_menvcfg(CPURISCVState *env,
> int csrno,
> const RISCVCPUConfig *cfg = riscv_cpu_cfg(env);
> uint64_t mask = MENVCFG_FIOM | MENVCFG_CBIE | MENVCFG_CBCFE |
> MENVCFG_CBZE | MENVCFG_CDE;
> + bool stce_changed = false;
>
> if (riscv_cpu_mxl(env) == MXL_RV64) {
> mask |= (cfg->ext_svpbmt ? MENVCFG_PBMTE : 0) |
> @@ -3181,10 +3182,19 @@ static RISCVException write_menvcfg(CPURISCVState
> *env, int csrno,
> if ((val & MENVCFG_DTE) == 0) {
> env->mstatus &= ~MSTATUS_SDT;
> }
> +
> + if (cfg->ext_sstc &&
> + ((env->menvcfg & MENVCFG_STCE) != (val & MENVCFG_STCE))) {
> + stce_changed = true;
> + }
> }
> env->menvcfg = (env->menvcfg & ~mask) | (val & mask);
> write_henvcfg(env, CSR_HENVCFG, env->henvcfg);
>
> + if (stce_changed) {
> + riscv_timer_stce_changed(env, true, !!(val & MENVCFG_STCE));
> + }
> +
> return RISCV_EXCP_NONE;
> }
>
> @@ -3207,6 +3217,12 @@ static RISCVException write_menvcfgh(CPURISCVState
> *env, int csrno,
> (cfg->ext_smcdeleg ? MENVCFG_CDE : 0) |
> (cfg->ext_ssdbltrp ? MENVCFG_DTE : 0);
> uint64_t valh = (uint64_t)val << 32;
> + bool stce_changed = false;
> +
> + if (cfg->ext_sstc &&
> + ((env->menvcfg & MENVCFG_STCE) != (valh & MENVCFG_STCE))) {
> + stce_changed = true;
> + }
>
> if ((valh & MENVCFG_DTE) == 0) {
> env->mstatus &= ~MSTATUS_SDT;
> @@ -3215,6 +3231,10 @@ static RISCVException write_menvcfgh(CPURISCVState
> *env, int csrno,
> env->menvcfg = (env->menvcfg & ~mask) | (valh & mask);
> write_henvcfgh(env, CSR_HENVCFGH, env->henvcfg >> 32);
>
> + if (stce_changed) {
> + riscv_timer_stce_changed(env, true, !!(valh & MENVCFG_STCE));
> + }
> +
> return RISCV_EXCP_NONE;
> }
>
> @@ -3292,8 +3312,10 @@ static RISCVException read_henvcfg(CPURISCVState *env,
> int csrno,
> static RISCVException write_henvcfg(CPURISCVState *env, int csrno,
> target_ulong val)
> {
> + const RISCVCPUConfig *cfg = riscv_cpu_cfg(env);
> uint64_t mask = HENVCFG_FIOM | HENVCFG_CBIE | HENVCFG_CBCFE |
> HENVCFG_CBZE;
> RISCVException ret;
> + bool stce_changed = false;
>
> ret = smstateen_acc_ok(env, 0, SMSTATEEN0_HSENVCFG);
> if (ret != RISCV_EXCP_NONE) {
> @@ -3319,6 +3341,11 @@ static RISCVException write_henvcfg(CPURISCVState
> *env, int csrno,
> get_field(val, HENVCFG_PMM) != PMM_FIELD_RESERVED) {
> mask |= HENVCFG_PMM;
> }
> +
> + if (cfg->ext_sstc &&
> + ((env->henvcfg & HENVCFG_STCE) != (val & HENVCFG_STCE))) {
> + stce_changed = true;
> + }
> }
>
> env->henvcfg = val & mask;
> @@ -3326,6 +3353,10 @@ static RISCVException write_henvcfg(CPURISCVState
> *env, int csrno,
> env->vsstatus &= ~MSTATUS_SDT;
> }
>
> + if (stce_changed) {
> + riscv_timer_stce_changed(env, false, !!(val & HENVCFG_STCE));
> + }
> +
> return RISCV_EXCP_NONE;
> }
>
> @@ -3347,19 +3378,32 @@ static RISCVException read_henvcfgh(CPURISCVState
> *env, int csrno,
> static RISCVException write_henvcfgh(CPURISCVState *env, int csrno,
> target_ulong val)
> {
> + const RISCVCPUConfig *cfg = riscv_cpu_cfg(env);
> uint64_t mask = env->menvcfg & (HENVCFG_PBMTE | HENVCFG_STCE |
> HENVCFG_ADUE | HENVCFG_DTE);
> uint64_t valh = (uint64_t)val << 32;
> RISCVException ret;
> + bool stce_changed = false;
>
> ret = smstateen_acc_ok(env, 0, SMSTATEEN0_HSENVCFG);
> if (ret != RISCV_EXCP_NONE) {
> return ret;
> }
> +
> + if (cfg->ext_sstc &&
> + ((env->henvcfg & HENVCFG_STCE) != (valh & HENVCFG_STCE))) {
> + stce_changed = true;
> + }
> +
> env->henvcfg = (env->henvcfg & 0xFFFFFFFF) | (valh & mask);
> if ((env->henvcfg & HENVCFG_DTE) == 0) {
> env->vsstatus &= ~MSTATUS_SDT;
> }
> +
> + if (stce_changed) {
> + riscv_timer_stce_changed(env, false, !!(val & HENVCFG_STCE));
> + }
> +
> return RISCV_EXCP_NONE;
> }
>
> diff --git a/target/riscv/time_helper.c b/target/riscv/time_helper.c
> index aebf0798d0..c648c9fac7 100644
> --- a/target/riscv/time_helper.c
> +++ b/target/riscv/time_helper.c
> @@ -140,6 +140,57 @@ void riscv_timer_write_timecmp(CPURISCVState *env,
> QEMUTimer *timer,
> timer_mod(timer, next);
> }
>
> +/*
> + * When disabling xenvcfg.STCE, the S/VS Timer may be disabled at the same
> time.
> + * It is safe to call this function regardless of whether the timer has been
> + * deleted or not. timer_del() will do nothing if the timer has already
> + * been deleted.
> + */
> +static void riscv_timer_disable_timecmp(CPURISCVState *env, QEMUTimer *timer,
> + uint32_t timer_irq)
> +{
> + /* Disable S-mode Timer IRQ and HW-based STIP */
> + if ((timer_irq == MIP_STIP) && !get_field(env->menvcfg, MENVCFG_STCE)) {
> + riscv_cpu_update_mip(env, timer_irq, BOOL_TO_MASK(0));
> + timer_del(timer);
> + return;
> + }
> +
> + /* Disable VS-mode Timer IRQ and HW-based VSTIP */
> + if ((timer_irq == MIP_VSTIP) &&
> + (!get_field(env->menvcfg, MENVCFG_STCE) ||
> + !get_field(env->henvcfg, HENVCFG_STCE))) {
> + env->vstime_irq = 0;
> + riscv_cpu_update_mip(env, 0, BOOL_TO_MASK(0));
> + timer_del(timer);
> + return;
> + }
> +}
> +
> +/* Enable or disable S/VS-mode Timer when xenvcfg.STCE is changed */
> +void riscv_timer_stce_changed(CPURISCVState *env, bool is_m_mode, bool
> enable)
> +{
> + if (is_m_mode) {
> + /* menvcfg.STCE changes */
> + if (enable) {
> + riscv_timer_write_timecmp(env, env->stimer, env->stimecmp, 0,
> MIP_STIP);
> + riscv_timer_write_timecmp(env, env->vstimer, env->vstimecmp,
> + env->htimedelta, MIP_VSTIP);
This line and ...
> + } else {
> + riscv_timer_disable_timecmp(env, env->stimer, MIP_STIP);
> + riscv_timer_disable_timecmp(env, env->vstimer, MIP_VSTIP);
This line are duplicated below.
> + }
> + } else {
We can remove the else
> + /* henvcfg.STCE changes */
> + if (enable) {
> + riscv_timer_write_timecmp(env, env->vstimer, env->vstimecmp,
> + env->htimedelta, MIP_VSTIP);
> + } else {
> + riscv_timer_disable_timecmp(env, env->vstimer, MIP_VSTIP);
> + }
and always run this branch to remove the duplicated code above
Alistair
> + }
> +}
> +
> void riscv_timer_init(RISCVCPU *cpu)
> {
> CPURISCVState *env;
> diff --git a/target/riscv/time_helper.h b/target/riscv/time_helper.h
> index cacd79b80c..af1f634f89 100644
> --- a/target/riscv/time_helper.h
> +++ b/target/riscv/time_helper.h
> @@ -25,6 +25,7 @@
> void riscv_timer_write_timecmp(CPURISCVState *env, QEMUTimer *timer,
> uint64_t timecmp, uint64_t delta,
> uint32_t timer_irq);
> +void riscv_timer_stce_changed(CPURISCVState *env, bool is_m_mode, bool
> enable);
> void riscv_timer_init(RISCVCPU *cpu);
>
> #endif
> --
> 2.17.1
>
>
