diff mbox series

[v7,2/3] target/riscv: Add stimecmp support

Message ID 20220803082516.2271344-3-atishp@rivosinc.com
State New
Headers show
Series Implement Sstc extension | expand

Commit Message

Atish Kumar Patra Aug. 3, 2022, 8:25 a.m. UTC
stimecmp allows the supervisor mode to update stimecmp CSR directly
to program the next timer interrupt. This CSR is part of the Sstc
extension which was ratified recently.

Signed-off-by: Atish Patra <atishp@rivosinc.com>
---
 target/riscv/cpu.c         | 12 +++++
 target/riscv/cpu.h         |  5 ++
 target/riscv/cpu_bits.h    |  4 ++
 target/riscv/csr.c         | 81 +++++++++++++++++++++++++++++++
 target/riscv/machine.c     |  1 +
 target/riscv/meson.build   |  3 +-
 target/riscv/time_helper.c | 98 ++++++++++++++++++++++++++++++++++++++
 target/riscv/time_helper.h | 30 ++++++++++++
 8 files changed, 233 insertions(+), 1 deletion(-)
 create mode 100644 target/riscv/time_helper.c
 create mode 100644 target/riscv/time_helper.h

Comments

Weiwei Li Aug. 3, 2022, 8:42 a.m. UTC | #1
在 2022/8/3 下午4:25, Atish Patra 写道:
> stimecmp allows the supervisor mode to update stimecmp CSR directly
> to program the next timer interrupt. This CSR is part of the Sstc
> extension which was ratified recently.
>
> Signed-off-by: Atish Patra <atishp@rivosinc.com>
> ---
>   target/riscv/cpu.c         | 12 +++++
>   target/riscv/cpu.h         |  5 ++
>   target/riscv/cpu_bits.h    |  4 ++
>   target/riscv/csr.c         | 81 +++++++++++++++++++++++++++++++
>   target/riscv/machine.c     |  1 +
>   target/riscv/meson.build   |  3 +-
>   target/riscv/time_helper.c | 98 ++++++++++++++++++++++++++++++++++++++
>   target/riscv/time_helper.h | 30 ++++++++++++
>   8 files changed, 233 insertions(+), 1 deletion(-)
>   create mode 100644 target/riscv/time_helper.c
>   create mode 100644 target/riscv/time_helper.h
>
> diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c
> index d4635c7df46b..e0c3e786849f 100644
> --- a/target/riscv/cpu.c
> +++ b/target/riscv/cpu.c
> @@ -23,6 +23,7 @@
>   #include "qemu/log.h"
>   #include "cpu.h"
>   #include "internals.h"
> +#include "time_helper.h"
>   #include "exec/exec-all.h"
>   #include "qapi/error.h"
>   #include "qemu/error-report.h"
> @@ -99,6 +100,7 @@ static const struct isa_ext_data isa_edata_arr[] = {
>       ISA_EXT_DATA_ENTRY(zve64f, true, PRIV_VERSION_1_12_0, ext_zve64f),
>       ISA_EXT_DATA_ENTRY(zhinx, true, PRIV_VERSION_1_12_0, ext_zhinx),
>       ISA_EXT_DATA_ENTRY(zhinxmin, true, PRIV_VERSION_1_12_0, ext_zhinxmin),
> +    ISA_EXT_DATA_ENTRY(sstc, true, PRIV_VERSION_1_12_0, ext_sstc),
>       ISA_EXT_DATA_ENTRY(svinval, true, PRIV_VERSION_1_12_0, ext_svinval),
>       ISA_EXT_DATA_ENTRY(svnapot, true, PRIV_VERSION_1_12_0, ext_svnapot),
>       ISA_EXT_DATA_ENTRY(svpbmt, true, PRIV_VERSION_1_12_0, ext_svpbmt),
> @@ -675,6 +677,13 @@ static void riscv_cpu_realize(DeviceState *dev, Error **errp)
>   
>       set_resetvec(env, cpu->cfg.resetvec);
>   
> +#ifndef CONFIG_USER_ONLY
> +    if (cpu->cfg.ext_sstc) {
> +        riscv_timer_init(cpu);
> +    }
> +#endif /* CONFIG_USER_ONLY */
> +
> +

multi blink line here.

Regards,

Weiwei Li

>       /* Validate that MISA_MXL is set properly. */
>       switch (env->misa_mxl_max) {
>   #ifdef TARGET_RISCV64
> @@ -968,7 +977,9 @@ static void riscv_cpu_init(Object *obj)
>   #ifndef CONFIG_USER_ONLY
>       qdev_init_gpio_in(DEVICE(cpu), riscv_cpu_set_irq,
>                         IRQ_LOCAL_MAX + IRQ_LOCAL_GUEST_MAX);
> +
>   #endif /* CONFIG_USER_ONLY */
> +
>   }
>   
>   static Property riscv_cpu_extensions[] = {
> @@ -995,6 +1006,7 @@ static Property riscv_cpu_extensions[] = {
>       DEFINE_PROP_BOOL("Zve64f", RISCVCPU, cfg.ext_zve64f, false),
>       DEFINE_PROP_BOOL("mmu", RISCVCPU, cfg.mmu, true),
>       DEFINE_PROP_BOOL("pmp", RISCVCPU, cfg.pmp, true),
> +    DEFINE_PROP_BOOL("sstc", RISCVCPU, cfg.ext_sstc, true),
>   
>       DEFINE_PROP_STRING("priv_spec", RISCVCPU, cfg.priv_spec),
>       DEFINE_PROP_STRING("vext_spec", RISCVCPU, cfg.vext_spec),
> diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
> index 0fae1569945c..4cda2905661e 100644
> --- a/target/riscv/cpu.h
> +++ b/target/riscv/cpu.h
> @@ -309,6 +309,9 @@ struct CPUArchState {
>       uint64_t mfromhost;
>       uint64_t mtohost;
>   
> +    /* Sstc CSRs */
> +    uint64_t stimecmp;
> +
>       /* physical memory protection */
>       pmp_table_t pmp_state;
>       target_ulong mseccfg;
> @@ -362,6 +365,7 @@ struct CPUArchState {
>       float_status fp_status;
>   
>       /* Fields from here on are preserved across CPU reset. */
> +    QEMUTimer *stimer; /* Internal timer for S-mode interrupt */
>   
>       hwaddr kernel_addr;
>       hwaddr fdt_addr;
> @@ -425,6 +429,7 @@ struct RISCVCPUConfig {
>       bool ext_ifencei;
>       bool ext_icsr;
>       bool ext_zihintpause;
> +    bool ext_sstc;
>       bool ext_svinval;
>       bool ext_svnapot;
>       bool ext_svpbmt;
> diff --git a/target/riscv/cpu_bits.h b/target/riscv/cpu_bits.h
> index 6be5a9e9f046..ac17cf1515c0 100644
> --- a/target/riscv/cpu_bits.h
> +++ b/target/riscv/cpu_bits.h
> @@ -206,6 +206,10 @@
>   #define CSR_STVAL           0x143
>   #define CSR_SIP             0x144
>   
> +/* Sstc supervisor CSRs */
> +#define CSR_STIMECMP        0x14D
> +#define CSR_STIMECMPH       0x15D
> +
>   /* Supervisor Protection and Translation */
>   #define CSR_SPTBR           0x180
>   #define CSR_SATP            0x180
> diff --git a/target/riscv/csr.c b/target/riscv/csr.c
> index 0fb042b2fd0f..b71e2509b64f 100644
> --- a/target/riscv/csr.c
> +++ b/target/riscv/csr.c
> @@ -22,6 +22,7 @@
>   #include "qemu/timer.h"
>   #include "cpu.h"
>   #include "pmu.h"
> +#include "time_helper.h"
>   #include "qemu/main-loop.h"
>   #include "exec/exec-all.h"
>   #include "sysemu/cpu-timers.h"
> @@ -803,6 +804,76 @@ static RISCVException read_timeh(CPURISCVState *env, int csrno,
>       return RISCV_EXCP_NONE;
>   }
>   
> +static RISCVException sstc(CPURISCVState *env, int csrno)
> +{
> +    CPUState *cs = env_cpu(env);
> +    RISCVCPU *cpu = RISCV_CPU(cs);
> +
> +    if (!cpu->cfg.ext_sstc || !env->rdtime_fn) {
> +        return RISCV_EXCP_ILLEGAL_INST;
> +    }
> +
> +    if (env->priv == PRV_M) {
> +        return RISCV_EXCP_NONE;
> +    }
> +
> +    if (env->priv != PRV_S) {
> +        return RISCV_EXCP_ILLEGAL_INST;
> +    }
> +

This check seems unnecessary here. Stimecmp is a S mode  csr. So any 
priv less than S

mode will trigger exception in csrrw related check and cannot reach here.

And maybe we need call smode predicate for it in this function.

> +    /*
> +     * No need of separate function for rv32 as menvcfg stores both menvcfg
> +     * menvcfgh for RV32.
> +     */
> +    if (!(get_field(env->mcounteren, COUNTEREN_TM) &&
> +          get_field(env->menvcfg, MENVCFG_STCE))) {
> +        return RISCV_EXCP_ILLEGAL_INST;
> +    }
> +
> +    return RISCV_EXCP_NONE;
> +}
> +
> +static RISCVException read_stimecmp(CPURISCVState *env, int csrno,
> +                                    target_ulong *val)
> +{
> +    *val = env->stimecmp;
> +    return RISCV_EXCP_NONE;
> +}
> +
> +static RISCVException read_stimecmph(CPURISCVState *env, int csrno,
> +                                    target_ulong *val)
> +{
> +    *val = env->stimecmp >> 32;
> +    return RISCV_EXCP_NONE;
> +}
> +
> +static RISCVException write_stimecmp(CPURISCVState *env, int csrno,
> +                                    target_ulong val)
> +{
> +    RISCVCPU *cpu = env_archcpu(env);
> +
> +    if (riscv_cpu_mxl(env) == MXL_RV32) {
> +        env->stimecmp = deposit64(env->stimecmp, 0, 32, (uint64_t)val);
> +    } else {
> +        env->stimecmp = val;
> +    }
> +
> +    riscv_timer_write_timecmp(cpu, env->stimer, env->stimecmp, 0, MIP_STIP);
> +
> +    return RISCV_EXCP_NONE;
> +}
> +
> +static RISCVException write_stimecmph(CPURISCVState *env, int csrno,
> +                                    target_ulong val)
> +{
> +    RISCVCPU *cpu = env_archcpu(env);
> +
> +    env->stimecmp = deposit64(env->stimecmp, 32, 32, (uint64_t)val);
> +    riscv_timer_write_timecmp(cpu, env->stimer, env->stimecmp, 0, MIP_STIP);
> +
> +    return RISCV_EXCP_NONE;
> +}
> +
>   /* Machine constants */
>   
>   #define M_MODE_INTERRUPTS  ((uint64_t)(MIP_MSIP | MIP_MTIP | MIP_MEIP))
> @@ -1719,6 +1790,12 @@ static RISCVException rmw_mip64(CPURISCVState *env, int csrno,
>           new_val |= env->external_seip * MIP_SEIP;
>       }
>   
> +    if (cpu->cfg.ext_sstc && (env->priv == PRV_M) &&
> +        get_field(env->menvcfg, MENVCFG_STCE)) {
> +        /* sstc extension forbids STIP & VSTIP to be writeable in mip */
> +        mask = mask & ~(MIP_STIP | MIP_VSTIP);
> +    }
> +
>       if (mask) {
>           old_mip = riscv_cpu_update_mip(cpu, mask, (new_val & mask));
>       } else {
> @@ -3584,6 +3661,10 @@ riscv_csr_operations csr_ops[CSR_TABLE_SIZE] = {
>       [CSR_SCAUSE]   = { "scause",   smode, read_scause,   write_scause   },
>       [CSR_STVAL]    = { "stval",    smode, read_stval,    write_stval    },
>       [CSR_SIP]      = { "sip",      smode, NULL,    NULL, rmw_sip        },
> +    [CSR_STIMECMP] = { "stimecmp", sstc, read_stimecmp, write_stimecmp,
> +                                          .min_priv_ver = PRIV_VERSION_1_12_0 },
> +    [CSR_STIMECMPH] = { "stimecmph", sstc, read_stimecmph, write_stimecmph,
> +                                          .min_priv_ver = PRIV_VERSION_1_12_0 },
>   
>       /* Supervisor Protection and Translation */
>       [CSR_SATP]     = { "satp",     smode, read_satp,     write_satp     },
> diff --git a/target/riscv/machine.c b/target/riscv/machine.c
> index b508b042cb73..622fface484e 100644
> --- a/target/riscv/machine.c
> +++ b/target/riscv/machine.c
> @@ -359,6 +359,7 @@ const VMStateDescription vmstate_riscv_cpu = {
>           VMSTATE_UINTTL(env.mscratch, RISCVCPU),
>           VMSTATE_UINT64(env.mfromhost, RISCVCPU),
>           VMSTATE_UINT64(env.mtohost, RISCVCPU),
> +        VMSTATE_UINT64(env.stimecmp, RISCVCPU),
>   
>           VMSTATE_END_OF_LIST()
>       },
> diff --git a/target/riscv/meson.build b/target/riscv/meson.build
> index 2c1975e72c4e..24893c614ee4 100644
> --- a/target/riscv/meson.build
> +++ b/target/riscv/meson.build
> @@ -31,7 +31,8 @@ riscv_softmmu_ss.add(files(
>     'debug.c',
>     'monitor.c',
>     'machine.c',
> -  'pmu.c'
> +  'pmu.c',
> +  'time_helper.c'
>   ))
>   
>   target_arch += {'riscv': riscv_ss}
> diff --git a/target/riscv/time_helper.c b/target/riscv/time_helper.c
> new file mode 100644
> index 000000000000..f3fb5eac7b7b
> --- /dev/null
> +++ b/target/riscv/time_helper.c
> @@ -0,0 +1,98 @@
> +/*
> + * RISC-V timer helper implementation.
> + *
> + * Copyright (c) 2022 Rivos Inc.
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms and conditions of the GNU General Public License,
> + * version 2 or later, as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope it will be useful, but WITHOUT
> + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
> + * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
> + * more details.
> + *
> + * You should have received a copy of the GNU General Public License along with
> + * this program.  If not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#include "qemu/osdep.h"
> +#include "qemu/log.h"
> +#include "cpu_bits.h"
> +#include "time_helper.h"
> +#include "hw/intc/riscv_aclint.h"
> +
> +static void riscv_stimer_cb(void *opaque)
> +{
> +    RISCVCPU *cpu = opaque;
> +    riscv_cpu_update_mip(cpu, MIP_STIP, BOOL_TO_MASK(1));
> +}
> +
> +/*
> + * Called when timecmp is written to update the QEMU timer or immediately
> + * trigger timer interrupt if mtimecmp <= current timer value.
> + */
> +void riscv_timer_write_timecmp(RISCVCPU *cpu, QEMUTimer *timer,
> +                               uint64_t timecmp, uint64_t delta,
> +                               uint32_t timer_irq)
> +{
> +    uint64_t diff, ns_diff, next;
> +    CPURISCVState *env = &cpu->env;
> +    RISCVAclintMTimerState *mtimer = env->rdtime_fn_arg;
> +    uint32_t timebase_freq = mtimer->timebase_freq;
> +    uint64_t rtc_r = env->rdtime_fn(env->rdtime_fn_arg) + delta;
> +
> +    if (timecmp <= rtc_r) {
> +        /*
> +         * If we're setting an stimecmp value in the "past",
> +         * immediately raise the timer interrupt
> +         */
> +        riscv_cpu_update_mip(cpu, timer_irq, BOOL_TO_MASK(1));
> +        return;
> +    }
> +
> +    /* Clear the [V]STIP bit in mip */
> +    riscv_cpu_update_mip(cpu, timer_irq, BOOL_TO_MASK(0));
> +
> +    /* otherwise, set up the future timer interrupt */
> +    diff = timecmp - rtc_r;
> +    /* back to ns (note args switched in muldiv64) */
> +    ns_diff = muldiv64(diff, NANOSECONDS_PER_SECOND, timebase_freq);
> +
> +    /*
> +     * check if ns_diff overflowed and check if the addition would potentially
> +     * overflow
> +     */
> +    if ((NANOSECONDS_PER_SECOND > timebase_freq && ns_diff < diff) ||
> +        ns_diff > INT64_MAX) {
> +        next = INT64_MAX;
> +    } else {
> +        /*
> +         * as it is very unlikely qemu_clock_get_ns will return a value
> +         * greater than INT64_MAX, no additional check is needed for an
> +         * unsigned integer overflow.
> +         */
> +        next = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + ns_diff;
> +        /*
> +         * if ns_diff is INT64_MAX next may still be outside the range
> +         * of a signed integer.
> +         */
> +        next = MIN(next, INT64_MAX);
> +    }
> +
> +    timer_mod(timer, next);
> +}
> +
> +void riscv_timer_init(RISCVCPU *cpu)
> +{
> +    CPURISCVState *env;
> +
> +    if (!cpu) {
> +        return;
> +    }
> +
> +    env = &cpu->env;
> +    env->stimer = timer_new_ns(QEMU_CLOCK_VIRTUAL, &riscv_stimer_cb, cpu);
> +    env->stimecmp = 0;
> +
> +}
> diff --git a/target/riscv/time_helper.h b/target/riscv/time_helper.h
> new file mode 100644
> index 000000000000..7b3cdcc35020
> --- /dev/null
> +++ b/target/riscv/time_helper.h
> @@ -0,0 +1,30 @@
> +/*
> + * RISC-V timer header file.
> + *
> + * Copyright (c) 2022 Rivos Inc.
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms and conditions of the GNU General Public License,
> + * version 2 or later, as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope it will be useful, but WITHOUT
> + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
> + * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
> + * more details.
> + *
> + * You should have received a copy of the GNU General Public License along with
> + * this program.  If not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#ifndef RISCV_TIME_HELPER_H
> +#define RISCV_TIME_HELPER_H
> +
> +#include "cpu.h"
> +#include "qemu/timer.h"
> +
> +void riscv_timer_write_timecmp(RISCVCPU *cpu, QEMUTimer *timer,
> +                               uint64_t timecmp, uint64_t delta,
> +                               uint32_t timer_irq);
> +void riscv_timer_init(RISCVCPU *cpu);
> +
> +#endif
Ben Dooks Aug. 3, 2022, 10:26 a.m. UTC | #2
On 03/08/2022 09:25, Atish Patra wrote:
> stimecmp allows the supervisor mode to update stimecmp CSR directly
> to program the next timer interrupt. This CSR is part of the Sstc
> extension which was ratified recently.
> 
> Signed-off-by: Atish Patra <atishp@rivosinc.com>
> ---
>   target/riscv/cpu.c         | 12 +++++
>   target/riscv/cpu.h         |  5 ++
>   target/riscv/cpu_bits.h    |  4 ++
>   target/riscv/csr.c         | 81 +++++++++++++++++++++++++++++++
>   target/riscv/machine.c     |  1 +
>   target/riscv/meson.build   |  3 +-
>   target/riscv/time_helper.c | 98 ++++++++++++++++++++++++++++++++++++++
>   target/riscv/time_helper.h | 30 ++++++++++++
>   8 files changed, 233 insertions(+), 1 deletion(-)
>   create mode 100644 target/riscv/time_helper.c
>   create mode 100644 target/riscv/time_helper.h
> 
> diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c
> index d4635c7df46b..e0c3e786849f 100644
> --- a/target/riscv/cpu.c
> +++ b/target/riscv/cpu.c
> @@ -23,6 +23,7 @@
>   #include "qemu/log.h"
>   #include "cpu.h"
>   #include "internals.h"
> +#include "time_helper.h"
>   #include "exec/exec-all.h"
>   #include "qapi/error.h"
>   #include "qemu/error-report.h"
> @@ -99,6 +100,7 @@ static const struct isa_ext_data isa_edata_arr[] = {
>       ISA_EXT_DATA_ENTRY(zve64f, true, PRIV_VERSION_1_12_0, ext_zve64f),
>       ISA_EXT_DATA_ENTRY(zhinx, true, PRIV_VERSION_1_12_0, ext_zhinx),
>       ISA_EXT_DATA_ENTRY(zhinxmin, true, PRIV_VERSION_1_12_0, ext_zhinxmin),
> +    ISA_EXT_DATA_ENTRY(sstc, true, PRIV_VERSION_1_12_0, ext_sstc),
>       ISA_EXT_DATA_ENTRY(svinval, true, PRIV_VERSION_1_12_0, ext_svinval),
>       ISA_EXT_DATA_ENTRY(svnapot, true, PRIV_VERSION_1_12_0, ext_svnapot),
>       ISA_EXT_DATA_ENTRY(svpbmt, true, PRIV_VERSION_1_12_0, ext_svpbmt),
> @@ -675,6 +677,13 @@ static void riscv_cpu_realize(DeviceState *dev, Error **errp)
>   
>       set_resetvec(env, cpu->cfg.resetvec);
>   
> +#ifndef CONFIG_USER_ONLY
> +    if (cpu->cfg.ext_sstc) {
> +        riscv_timer_init(cpu);
> +    }
> +#endif /* CONFIG_USER_ONLY */
> +
> +
>       /* Validate that MISA_MXL is set properly. */
>       switch (env->misa_mxl_max) {
>   #ifdef TARGET_RISCV64
> @@ -968,7 +977,9 @@ static void riscv_cpu_init(Object *obj)
>   #ifndef CONFIG_USER_ONLY
>       qdev_init_gpio_in(DEVICE(cpu), riscv_cpu_set_irq,
>                         IRQ_LOCAL_MAX + IRQ_LOCAL_GUEST_MAX);
> +
>   #endif /* CONFIG_USER_ONLY */
> +
>   }
>   
>   static Property riscv_cpu_extensions[] = {
> @@ -995,6 +1006,7 @@ static Property riscv_cpu_extensions[] = {
>       DEFINE_PROP_BOOL("Zve64f", RISCVCPU, cfg.ext_zve64f, false),
>       DEFINE_PROP_BOOL("mmu", RISCVCPU, cfg.mmu, true),
>       DEFINE_PROP_BOOL("pmp", RISCVCPU, cfg.pmp, true),
> +    DEFINE_PROP_BOOL("sstc", RISCVCPU, cfg.ext_sstc, true),
>   
>       DEFINE_PROP_STRING("priv_spec", RISCVCPU, cfg.priv_spec),
>       DEFINE_PROP_STRING("vext_spec", RISCVCPU, cfg.vext_spec),
> diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
> index 0fae1569945c..4cda2905661e 100644
> --- a/target/riscv/cpu.h
> +++ b/target/riscv/cpu.h
> @@ -309,6 +309,9 @@ struct CPUArchState {
>       uint64_t mfromhost;
>       uint64_t mtohost;
>   
> +    /* Sstc CSRs */
> +    uint64_t stimecmp;
> +
>       /* physical memory protection */
>       pmp_table_t pmp_state;
>       target_ulong mseccfg;
> @@ -362,6 +365,7 @@ struct CPUArchState {
>       float_status fp_status;
>   
>       /* Fields from here on are preserved across CPU reset. */
> +    QEMUTimer *stimer; /* Internal timer for S-mode interrupt */
>   
>       hwaddr kernel_addr;
>       hwaddr fdt_addr;
> @@ -425,6 +429,7 @@ struct RISCVCPUConfig {
>       bool ext_ifencei;
>       bool ext_icsr;
>       bool ext_zihintpause;
> +    bool ext_sstc;
>       bool ext_svinval;
>       bool ext_svnapot;
>       bool ext_svpbmt;
> diff --git a/target/riscv/cpu_bits.h b/target/riscv/cpu_bits.h
> index 6be5a9e9f046..ac17cf1515c0 100644
> --- a/target/riscv/cpu_bits.h
> +++ b/target/riscv/cpu_bits.h
> @@ -206,6 +206,10 @@
>   #define CSR_STVAL           0x143
>   #define CSR_SIP             0x144
>   
> +/* Sstc supervisor CSRs */
> +#define CSR_STIMECMP        0x14D
> +#define CSR_STIMECMPH       0x15D
> +
>   /* Supervisor Protection and Translation */
>   #define CSR_SPTBR           0x180
>   #define CSR_SATP            0x180
> diff --git a/target/riscv/csr.c b/target/riscv/csr.c
> index 0fb042b2fd0f..b71e2509b64f 100644
> --- a/target/riscv/csr.c
> +++ b/target/riscv/csr.c
> @@ -22,6 +22,7 @@
>   #include "qemu/timer.h"
>   #include "cpu.h"
>   #include "pmu.h"
> +#include "time_helper.h"
>   #include "qemu/main-loop.h"
>   #include "exec/exec-all.h"
>   #include "sysemu/cpu-timers.h"
> @@ -803,6 +804,76 @@ static RISCVException read_timeh(CPURISCVState *env, int csrno,
>       return RISCV_EXCP_NONE;
>   }
>   
> +static RISCVException sstc(CPURISCVState *env, int csrno)
> +{
> +    CPUState *cs = env_cpu(env);
> +    RISCVCPU *cpu = RISCV_CPU(cs);
> +
> +    if (!cpu->cfg.ext_sstc || !env->rdtime_fn) {
> +        return RISCV_EXCP_ILLEGAL_INST;
> +    }
> +
> +    if (env->priv == PRV_M) {
> +        return RISCV_EXCP_NONE;
> +    }
> +
> +    if (env->priv != PRV_S) {
> +        return RISCV_EXCP_ILLEGAL_INST;
> +    }

These seem to be checking env->priv twice, wouldnt
one check for nv->priv != PRV_S be sufficient?
Atish Kumar Patra Aug. 3, 2022, 9:09 p.m. UTC | #3
On Wed, Aug 3, 2022 at 1:42 AM Weiwei Li <liweiwei@iscas.ac.cn> wrote:

>
> 在 2022/8/3 下午4:25, Atish Patra 写道:
> > stimecmp allows the supervisor mode to update stimecmp CSR directly
> > to program the next timer interrupt. This CSR is part of the Sstc
> > extension which was ratified recently.
> >
> > Signed-off-by: Atish Patra <atishp@rivosinc.com>
> > ---
> >   target/riscv/cpu.c         | 12 +++++
> >   target/riscv/cpu.h         |  5 ++
> >   target/riscv/cpu_bits.h    |  4 ++
> >   target/riscv/csr.c         | 81 +++++++++++++++++++++++++++++++
> >   target/riscv/machine.c     |  1 +
> >   target/riscv/meson.build   |  3 +-
> >   target/riscv/time_helper.c | 98 ++++++++++++++++++++++++++++++++++++++
> >   target/riscv/time_helper.h | 30 ++++++++++++
> >   8 files changed, 233 insertions(+), 1 deletion(-)
> >   create mode 100644 target/riscv/time_helper.c
> >   create mode 100644 target/riscv/time_helper.h
> >
> > diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c
> > index d4635c7df46b..e0c3e786849f 100644
> > --- a/target/riscv/cpu.c
> > +++ b/target/riscv/cpu.c
> > @@ -23,6 +23,7 @@
> >   #include "qemu/log.h"
> >   #include "cpu.h"
> >   #include "internals.h"
> > +#include "time_helper.h"
> >   #include "exec/exec-all.h"
> >   #include "qapi/error.h"
> >   #include "qemu/error-report.h"
> > @@ -99,6 +100,7 @@ static const struct isa_ext_data isa_edata_arr[] = {
> >       ISA_EXT_DATA_ENTRY(zve64f, true, PRIV_VERSION_1_12_0, ext_zve64f),
> >       ISA_EXT_DATA_ENTRY(zhinx, true, PRIV_VERSION_1_12_0, ext_zhinx),
> >       ISA_EXT_DATA_ENTRY(zhinxmin, true, PRIV_VERSION_1_12_0,
> ext_zhinxmin),
> > +    ISA_EXT_DATA_ENTRY(sstc, true, PRIV_VERSION_1_12_0, ext_sstc),
> >       ISA_EXT_DATA_ENTRY(svinval, true, PRIV_VERSION_1_12_0,
> ext_svinval),
> >       ISA_EXT_DATA_ENTRY(svnapot, true, PRIV_VERSION_1_12_0,
> ext_svnapot),
> >       ISA_EXT_DATA_ENTRY(svpbmt, true, PRIV_VERSION_1_12_0, ext_svpbmt),
> > @@ -675,6 +677,13 @@ static void riscv_cpu_realize(DeviceState *dev,
> Error **errp)
> >
> >       set_resetvec(env, cpu->cfg.resetvec);
> >
> > +#ifndef CONFIG_USER_ONLY
> > +    if (cpu->cfg.ext_sstc) {
> > +        riscv_timer_init(cpu);
> > +    }
> > +#endif /* CONFIG_USER_ONLY */
> > +
> > +
>
> multi blink line here.
>
>
Fixed it.


> Regards,
>
> Weiwei Li
>
> >       /* Validate that MISA_MXL is set properly. */
> >       switch (env->misa_mxl_max) {
> >   #ifdef TARGET_RISCV64
> > @@ -968,7 +977,9 @@ static void riscv_cpu_init(Object *obj)
> >   #ifndef CONFIG_USER_ONLY
> >       qdev_init_gpio_in(DEVICE(cpu), riscv_cpu_set_irq,
> >                         IRQ_LOCAL_MAX + IRQ_LOCAL_GUEST_MAX);
> > +
> >   #endif /* CONFIG_USER_ONLY */
> > +
> >   }
> >
> >   static Property riscv_cpu_extensions[] = {
> > @@ -995,6 +1006,7 @@ static Property riscv_cpu_extensions[] = {
> >       DEFINE_PROP_BOOL("Zve64f", RISCVCPU, cfg.ext_zve64f, false),
> >       DEFINE_PROP_BOOL("mmu", RISCVCPU, cfg.mmu, true),
> >       DEFINE_PROP_BOOL("pmp", RISCVCPU, cfg.pmp, true),
> > +    DEFINE_PROP_BOOL("sstc", RISCVCPU, cfg.ext_sstc, true),
> >
> >       DEFINE_PROP_STRING("priv_spec", RISCVCPU, cfg.priv_spec),
> >       DEFINE_PROP_STRING("vext_spec", RISCVCPU, cfg.vext_spec),
> > diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
> > index 0fae1569945c..4cda2905661e 100644
> > --- a/target/riscv/cpu.h
> > +++ b/target/riscv/cpu.h
> > @@ -309,6 +309,9 @@ struct CPUArchState {
> >       uint64_t mfromhost;
> >       uint64_t mtohost;
> >
> > +    /* Sstc CSRs */
> > +    uint64_t stimecmp;
> > +
> >       /* physical memory protection */
> >       pmp_table_t pmp_state;
> >       target_ulong mseccfg;
> > @@ -362,6 +365,7 @@ struct CPUArchState {
> >       float_status fp_status;
> >
> >       /* Fields from here on are preserved across CPU reset. */
> > +    QEMUTimer *stimer; /* Internal timer for S-mode interrupt */
> >
> >       hwaddr kernel_addr;
> >       hwaddr fdt_addr;
> > @@ -425,6 +429,7 @@ struct RISCVCPUConfig {
> >       bool ext_ifencei;
> >       bool ext_icsr;
> >       bool ext_zihintpause;
> > +    bool ext_sstc;
> >       bool ext_svinval;
> >       bool ext_svnapot;
> >       bool ext_svpbmt;
> > diff --git a/target/riscv/cpu_bits.h b/target/riscv/cpu_bits.h
> > index 6be5a9e9f046..ac17cf1515c0 100644
> > --- a/target/riscv/cpu_bits.h
> > +++ b/target/riscv/cpu_bits.h
> > @@ -206,6 +206,10 @@
> >   #define CSR_STVAL           0x143
> >   #define CSR_SIP             0x144
> >
> > +/* Sstc supervisor CSRs */
> > +#define CSR_STIMECMP        0x14D
> > +#define CSR_STIMECMPH       0x15D
> > +
> >   /* Supervisor Protection and Translation */
> >   #define CSR_SPTBR           0x180
> >   #define CSR_SATP            0x180
> > diff --git a/target/riscv/csr.c b/target/riscv/csr.c
> > index 0fb042b2fd0f..b71e2509b64f 100644
> > --- a/target/riscv/csr.c
> > +++ b/target/riscv/csr.c
> > @@ -22,6 +22,7 @@
> >   #include "qemu/timer.h"
> >   #include "cpu.h"
> >   #include "pmu.h"
> > +#include "time_helper.h"
> >   #include "qemu/main-loop.h"
> >   #include "exec/exec-all.h"
> >   #include "sysemu/cpu-timers.h"
> > @@ -803,6 +804,76 @@ static RISCVException read_timeh(CPURISCVState
> *env, int csrno,
> >       return RISCV_EXCP_NONE;
> >   }
> >
> > +static RISCVException sstc(CPURISCVState *env, int csrno)
> > +{
> > +    CPUState *cs = env_cpu(env);
> > +    RISCVCPU *cpu = RISCV_CPU(cs);
> > +
> > +    if (!cpu->cfg.ext_sstc || !env->rdtime_fn) {
> > +        return RISCV_EXCP_ILLEGAL_INST;
> > +    }
> > +
> > +    if (env->priv == PRV_M) {
> > +        return RISCV_EXCP_NONE;
> > +    }
> > +
> > +    if (env->priv != PRV_S) {
> > +        return RISCV_EXCP_ILLEGAL_INST;
> > +    }
> > +
>
> This check seems unnecessary here. Stimecmp is a S mode  csr. So any
> priv less than S
>
> mode will trigger exception in csrrw related check and cannot reach here.
>
>
Yeah. We can remove it.


> And maybe we need call smode predicate for it in this function.
>
>
You mean at the end instead of returning RISCV_EXCP_NONE ? We can do that.


> > +    /*
> > +     * No need of separate function for rv32 as menvcfg stores both
> menvcfg
> > +     * menvcfgh for RV32.
> > +     */
> > +    if (!(get_field(env->mcounteren, COUNTEREN_TM) &&
> > +          get_field(env->menvcfg, MENVCFG_STCE))) {
> > +        return RISCV_EXCP_ILLEGAL_INST;
> > +    }
> > +
> > +    return RISCV_EXCP_NONE;
> > +}
> > +
> > +static RISCVException read_stimecmp(CPURISCVState *env, int csrno,
> > +                                    target_ulong *val)
> > +{
> > +    *val = env->stimecmp;
> > +    return RISCV_EXCP_NONE;
> > +}
> > +
> > +static RISCVException read_stimecmph(CPURISCVState *env, int csrno,
> > +                                    target_ulong *val)
> > +{
> > +    *val = env->stimecmp >> 32;
> > +    return RISCV_EXCP_NONE;
> > +}
> > +
> > +static RISCVException write_stimecmp(CPURISCVState *env, int csrno,
> > +                                    target_ulong val)
> > +{
> > +    RISCVCPU *cpu = env_archcpu(env);
> > +
> > +    if (riscv_cpu_mxl(env) == MXL_RV32) {
> > +        env->stimecmp = deposit64(env->stimecmp, 0, 32, (uint64_t)val);
> > +    } else {
> > +        env->stimecmp = val;
> > +    }
> > +
> > +    riscv_timer_write_timecmp(cpu, env->stimer, env->stimecmp, 0,
> MIP_STIP);
> > +
> > +    return RISCV_EXCP_NONE;
> > +}
> > +
> > +static RISCVException write_stimecmph(CPURISCVState *env, int csrno,
> > +                                    target_ulong val)
> > +{
> > +    RISCVCPU *cpu = env_archcpu(env);
> > +
> > +    env->stimecmp = deposit64(env->stimecmp, 32, 32, (uint64_t)val);
> > +    riscv_timer_write_timecmp(cpu, env->stimer, env->stimecmp, 0,
> MIP_STIP);
> > +
> > +    return RISCV_EXCP_NONE;
> > +}
> > +
> >   /* Machine constants */
> >
> >   #define M_MODE_INTERRUPTS  ((uint64_t)(MIP_MSIP | MIP_MTIP | MIP_MEIP))
> > @@ -1719,6 +1790,12 @@ static RISCVException rmw_mip64(CPURISCVState
> *env, int csrno,
> >           new_val |= env->external_seip * MIP_SEIP;
> >       }
> >
> > +    if (cpu->cfg.ext_sstc && (env->priv == PRV_M) &&
> > +        get_field(env->menvcfg, MENVCFG_STCE)) {
> > +        /* sstc extension forbids STIP & VSTIP to be writeable in mip */
> > +        mask = mask & ~(MIP_STIP | MIP_VSTIP);
> > +    }
> > +
> >       if (mask) {
> >           old_mip = riscv_cpu_update_mip(cpu, mask, (new_val & mask));
> >       } else {
> > @@ -3584,6 +3661,10 @@ riscv_csr_operations csr_ops[CSR_TABLE_SIZE] = {
> >       [CSR_SCAUSE]   = { "scause",   smode, read_scause,   write_scause
>  },
> >       [CSR_STVAL]    = { "stval",    smode, read_stval,    write_stval
>   },
> >       [CSR_SIP]      = { "sip",      smode, NULL,    NULL, rmw_sip
>   },
> > +    [CSR_STIMECMP] = { "stimecmp", sstc, read_stimecmp, write_stimecmp,
> > +                                          .min_priv_ver =
> PRIV_VERSION_1_12_0 },
> > +    [CSR_STIMECMPH] = { "stimecmph", sstc, read_stimecmph,
> write_stimecmph,
> > +                                          .min_priv_ver =
> PRIV_VERSION_1_12_0 },
> >
> >       /* Supervisor Protection and Translation */
> >       [CSR_SATP]     = { "satp",     smode, read_satp,     write_satp
>  },
> > diff --git a/target/riscv/machine.c b/target/riscv/machine.c
> > index b508b042cb73..622fface484e 100644
> > --- a/target/riscv/machine.c
> > +++ b/target/riscv/machine.c
> > @@ -359,6 +359,7 @@ const VMStateDescription vmstate_riscv_cpu = {
> >           VMSTATE_UINTTL(env.mscratch, RISCVCPU),
> >           VMSTATE_UINT64(env.mfromhost, RISCVCPU),
> >           VMSTATE_UINT64(env.mtohost, RISCVCPU),
> > +        VMSTATE_UINT64(env.stimecmp, RISCVCPU),
> >
> >           VMSTATE_END_OF_LIST()
> >       },
> > diff --git a/target/riscv/meson.build b/target/riscv/meson.build
> > index 2c1975e72c4e..24893c614ee4 100644
> > --- a/target/riscv/meson.build
> > +++ b/target/riscv/meson.build
> > @@ -31,7 +31,8 @@ riscv_softmmu_ss.add(files(
> >     'debug.c',
> >     'monitor.c',
> >     'machine.c',
> > -  'pmu.c'
> > +  'pmu.c',
> > +  'time_helper.c'
> >   ))
> >
> >   target_arch += {'riscv': riscv_ss}
> > diff --git a/target/riscv/time_helper.c b/target/riscv/time_helper.c
> > new file mode 100644
> > index 000000000000..f3fb5eac7b7b
> > --- /dev/null
> > +++ b/target/riscv/time_helper.c
> > @@ -0,0 +1,98 @@
> > +/*
> > + * RISC-V timer helper implementation.
> > + *
> > + * Copyright (c) 2022 Rivos Inc.
> > + *
> > + * This program is free software; you can redistribute it and/or modify
> it
> > + * under the terms and conditions of the GNU General Public License,
> > + * version 2 or later, as published by the Free Software Foundation.
> > + *
> > + * This program is distributed in the hope it will be useful, but
> WITHOUT
> > + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
> > + * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public
> License for
> > + * more details.
> > + *
> > + * You should have received a copy of the GNU General Public License
> along with
> > + * this program.  If not, see <http://www.gnu.org/licenses/>.
> > + */
> > +
> > +#include "qemu/osdep.h"
> > +#include "qemu/log.h"
> > +#include "cpu_bits.h"
> > +#include "time_helper.h"
> > +#include "hw/intc/riscv_aclint.h"
> > +
> > +static void riscv_stimer_cb(void *opaque)
> > +{
> > +    RISCVCPU *cpu = opaque;
> > +    riscv_cpu_update_mip(cpu, MIP_STIP, BOOL_TO_MASK(1));
> > +}
> > +
> > +/*
> > + * Called when timecmp is written to update the QEMU timer or
> immediately
> > + * trigger timer interrupt if mtimecmp <= current timer value.
> > + */
> > +void riscv_timer_write_timecmp(RISCVCPU *cpu, QEMUTimer *timer,
> > +                               uint64_t timecmp, uint64_t delta,
> > +                               uint32_t timer_irq)
> > +{
> > +    uint64_t diff, ns_diff, next;
> > +    CPURISCVState *env = &cpu->env;
> > +    RISCVAclintMTimerState *mtimer = env->rdtime_fn_arg;
> > +    uint32_t timebase_freq = mtimer->timebase_freq;
> > +    uint64_t rtc_r = env->rdtime_fn(env->rdtime_fn_arg) + delta;
> > +
> > +    if (timecmp <= rtc_r) {
> > +        /*
> > +         * If we're setting an stimecmp value in the "past",
> > +         * immediately raise the timer interrupt
> > +         */
> > +        riscv_cpu_update_mip(cpu, timer_irq, BOOL_TO_MASK(1));
> > +        return;
> > +    }
> > +
> > +    /* Clear the [V]STIP bit in mip */
> > +    riscv_cpu_update_mip(cpu, timer_irq, BOOL_TO_MASK(0));
> > +
> > +    /* otherwise, set up the future timer interrupt */
> > +    diff = timecmp - rtc_r;
> > +    /* back to ns (note args switched in muldiv64) */
> > +    ns_diff = muldiv64(diff, NANOSECONDS_PER_SECOND, timebase_freq);
> > +
> > +    /*
> > +     * check if ns_diff overflowed and check if the addition would
> potentially
> > +     * overflow
> > +     */
> > +    if ((NANOSECONDS_PER_SECOND > timebase_freq && ns_diff < diff) ||
> > +        ns_diff > INT64_MAX) {
> > +        next = INT64_MAX;
> > +    } else {
> > +        /*
> > +         * as it is very unlikely qemu_clock_get_ns will return a value
> > +         * greater than INT64_MAX, no additional check is needed for an
> > +         * unsigned integer overflow.
> > +         */
> > +        next = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + ns_diff;
> > +        /*
> > +         * if ns_diff is INT64_MAX next may still be outside the range
> > +         * of a signed integer.
> > +         */
> > +        next = MIN(next, INT64_MAX);
> > +    }
> > +
> > +    timer_mod(timer, next);
> > +}
> > +
> > +void riscv_timer_init(RISCVCPU *cpu)
> > +{
> > +    CPURISCVState *env;
> > +
> > +    if (!cpu) {
> > +        return;
> > +    }
> > +
> > +    env = &cpu->env;
> > +    env->stimer = timer_new_ns(QEMU_CLOCK_VIRTUAL, &riscv_stimer_cb,
> cpu);
> > +    env->stimecmp = 0;
> > +
> > +}
> > diff --git a/target/riscv/time_helper.h b/target/riscv/time_helper.h
> > new file mode 100644
> > index 000000000000..7b3cdcc35020
> > --- /dev/null
> > +++ b/target/riscv/time_helper.h
> > @@ -0,0 +1,30 @@
> > +/*
> > + * RISC-V timer header file.
> > + *
> > + * Copyright (c) 2022 Rivos Inc.
> > + *
> > + * This program is free software; you can redistribute it and/or modify
> it
> > + * under the terms and conditions of the GNU General Public License,
> > + * version 2 or later, as published by the Free Software Foundation.
> > + *
> > + * This program is distributed in the hope it will be useful, but
> WITHOUT
> > + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
> > + * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public
> License for
> > + * more details.
> > + *
> > + * You should have received a copy of the GNU General Public License
> along with
> > + * this program.  If not, see <http://www.gnu.org/licenses/>.
> > + */
> > +
> > +#ifndef RISCV_TIME_HELPER_H
> > +#define RISCV_TIME_HELPER_H
> > +
> > +#include "cpu.h"
> > +#include "qemu/timer.h"
> > +
> > +void riscv_timer_write_timecmp(RISCVCPU *cpu, QEMUTimer *timer,
> > +                               uint64_t timecmp, uint64_t delta,
> > +                               uint32_t timer_irq);
> > +void riscv_timer_init(RISCVCPU *cpu);
> > +
> > +#endif
>
>
Atish Kumar Patra Aug. 3, 2022, 9:11 p.m. UTC | #4
On Wed, Aug 3, 2022 at 3:26 AM Ben Dooks <ben.dooks@codethink.co.uk> wrote:

> On 03/08/2022 09:25, Atish Patra wrote:
> > stimecmp allows the supervisor mode to update stimecmp CSR directly
> > to program the next timer interrupt. This CSR is part of the Sstc
> > extension which was ratified recently.
> >
> > Signed-off-by: Atish Patra <atishp@rivosinc.com>
> > ---
> >   target/riscv/cpu.c         | 12 +++++
> >   target/riscv/cpu.h         |  5 ++
> >   target/riscv/cpu_bits.h    |  4 ++
> >   target/riscv/csr.c         | 81 +++++++++++++++++++++++++++++++
> >   target/riscv/machine.c     |  1 +
> >   target/riscv/meson.build   |  3 +-
> >   target/riscv/time_helper.c | 98 ++++++++++++++++++++++++++++++++++++++
> >   target/riscv/time_helper.h | 30 ++++++++++++
> >   8 files changed, 233 insertions(+), 1 deletion(-)
> >   create mode 100644 target/riscv/time_helper.c
> >   create mode 100644 target/riscv/time_helper.h
> >
> > diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c
> > index d4635c7df46b..e0c3e786849f 100644
> > --- a/target/riscv/cpu.c
> > +++ b/target/riscv/cpu.c
> > @@ -23,6 +23,7 @@
> >   #include "qemu/log.h"
> >   #include "cpu.h"
> >   #include "internals.h"
> > +#include "time_helper.h"
> >   #include "exec/exec-all.h"
> >   #include "qapi/error.h"
> >   #include "qemu/error-report.h"
> > @@ -99,6 +100,7 @@ static const struct isa_ext_data isa_edata_arr[] = {
> >       ISA_EXT_DATA_ENTRY(zve64f, true, PRIV_VERSION_1_12_0, ext_zve64f),
> >       ISA_EXT_DATA_ENTRY(zhinx, true, PRIV_VERSION_1_12_0, ext_zhinx),
> >       ISA_EXT_DATA_ENTRY(zhinxmin, true, PRIV_VERSION_1_12_0,
> ext_zhinxmin),
> > +    ISA_EXT_DATA_ENTRY(sstc, true, PRIV_VERSION_1_12_0, ext_sstc),
> >       ISA_EXT_DATA_ENTRY(svinval, true, PRIV_VERSION_1_12_0,
> ext_svinval),
> >       ISA_EXT_DATA_ENTRY(svnapot, true, PRIV_VERSION_1_12_0,
> ext_svnapot),
> >       ISA_EXT_DATA_ENTRY(svpbmt, true, PRIV_VERSION_1_12_0, ext_svpbmt),
> > @@ -675,6 +677,13 @@ static void riscv_cpu_realize(DeviceState *dev,
> Error **errp)
> >
> >       set_resetvec(env, cpu->cfg.resetvec);
> >
> > +#ifndef CONFIG_USER_ONLY
> > +    if (cpu->cfg.ext_sstc) {
> > +        riscv_timer_init(cpu);
> > +    }
> > +#endif /* CONFIG_USER_ONLY */
> > +
> > +
> >       /* Validate that MISA_MXL is set properly. */
> >       switch (env->misa_mxl_max) {
> >   #ifdef TARGET_RISCV64
> > @@ -968,7 +977,9 @@ static void riscv_cpu_init(Object *obj)
> >   #ifndef CONFIG_USER_ONLY
> >       qdev_init_gpio_in(DEVICE(cpu), riscv_cpu_set_irq,
> >                         IRQ_LOCAL_MAX + IRQ_LOCAL_GUEST_MAX);
> > +
> >   #endif /* CONFIG_USER_ONLY */
> > +
> >   }
> >
> >   static Property riscv_cpu_extensions[] = {
> > @@ -995,6 +1006,7 @@ static Property riscv_cpu_extensions[] = {
> >       DEFINE_PROP_BOOL("Zve64f", RISCVCPU, cfg.ext_zve64f, false),
> >       DEFINE_PROP_BOOL("mmu", RISCVCPU, cfg.mmu, true),
> >       DEFINE_PROP_BOOL("pmp", RISCVCPU, cfg.pmp, true),
> > +    DEFINE_PROP_BOOL("sstc", RISCVCPU, cfg.ext_sstc, true),
> >
> >       DEFINE_PROP_STRING("priv_spec", RISCVCPU, cfg.priv_spec),
> >       DEFINE_PROP_STRING("vext_spec", RISCVCPU, cfg.vext_spec),
> > diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
> > index 0fae1569945c..4cda2905661e 100644
> > --- a/target/riscv/cpu.h
> > +++ b/target/riscv/cpu.h
> > @@ -309,6 +309,9 @@ struct CPUArchState {
> >       uint64_t mfromhost;
> >       uint64_t mtohost;
> >
> > +    /* Sstc CSRs */
> > +    uint64_t stimecmp;
> > +
> >       /* physical memory protection */
> >       pmp_table_t pmp_state;
> >       target_ulong mseccfg;
> > @@ -362,6 +365,7 @@ struct CPUArchState {
> >       float_status fp_status;
> >
> >       /* Fields from here on are preserved across CPU reset. */
> > +    QEMUTimer *stimer; /* Internal timer for S-mode interrupt */
> >
> >       hwaddr kernel_addr;
> >       hwaddr fdt_addr;
> > @@ -425,6 +429,7 @@ struct RISCVCPUConfig {
> >       bool ext_ifencei;
> >       bool ext_icsr;
> >       bool ext_zihintpause;
> > +    bool ext_sstc;
> >       bool ext_svinval;
> >       bool ext_svnapot;
> >       bool ext_svpbmt;
> > diff --git a/target/riscv/cpu_bits.h b/target/riscv/cpu_bits.h
> > index 6be5a9e9f046..ac17cf1515c0 100644
> > --- a/target/riscv/cpu_bits.h
> > +++ b/target/riscv/cpu_bits.h
> > @@ -206,6 +206,10 @@
> >   #define CSR_STVAL           0x143
> >   #define CSR_SIP             0x144
> >
> > +/* Sstc supervisor CSRs */
> > +#define CSR_STIMECMP        0x14D
> > +#define CSR_STIMECMPH       0x15D
> > +
> >   /* Supervisor Protection and Translation */
> >   #define CSR_SPTBR           0x180
> >   #define CSR_SATP            0x180
> > diff --git a/target/riscv/csr.c b/target/riscv/csr.c
> > index 0fb042b2fd0f..b71e2509b64f 100644
> > --- a/target/riscv/csr.c
> > +++ b/target/riscv/csr.c
> > @@ -22,6 +22,7 @@
> >   #include "qemu/timer.h"
> >   #include "cpu.h"
> >   #include "pmu.h"
> > +#include "time_helper.h"
> >   #include "qemu/main-loop.h"
> >   #include "exec/exec-all.h"
> >   #include "sysemu/cpu-timers.h"
> > @@ -803,6 +804,76 @@ static RISCVException read_timeh(CPURISCVState
> *env, int csrno,
> >       return RISCV_EXCP_NONE;
> >   }
> >
> > +static RISCVException sstc(CPURISCVState *env, int csrno)
> > +{
> > +    CPUState *cs = env_cpu(env);
> > +    RISCVCPU *cpu = RISCV_CPU(cs);
> > +
> > +    if (!cpu->cfg.ext_sstc || !env->rdtime_fn) {
> > +        return RISCV_EXCP_ILLEGAL_INST;
> > +    }
> > +
> > +    if (env->priv == PRV_M) {
> > +        return RISCV_EXCP_NONE;
> > +    }
> > +
> > +    if (env->priv != PRV_S) {
> > +        return RISCV_EXCP_ILLEGAL_INST;
> > +    }
>
> These seem to be checking env->priv twice, wouldnt
> one check for nv->priv != PRV_S be sufficient?
>
>
nope as we need to allow the access from M-mode unconditionally.
But we can remove the non-Smode check as suggested by Weiwei.


>
> --
> Ben Dooks                               http://www.codethink.co.uk/
> Senior Engineer                         Codethink - Providing Genius
>
> https://www.codethink.co.uk/privacy.html
>
diff mbox series

Patch

diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c
index d4635c7df46b..e0c3e786849f 100644
--- a/target/riscv/cpu.c
+++ b/target/riscv/cpu.c
@@ -23,6 +23,7 @@ 
 #include "qemu/log.h"
 #include "cpu.h"
 #include "internals.h"
+#include "time_helper.h"
 #include "exec/exec-all.h"
 #include "qapi/error.h"
 #include "qemu/error-report.h"
@@ -99,6 +100,7 @@  static const struct isa_ext_data isa_edata_arr[] = {
     ISA_EXT_DATA_ENTRY(zve64f, true, PRIV_VERSION_1_12_0, ext_zve64f),
     ISA_EXT_DATA_ENTRY(zhinx, true, PRIV_VERSION_1_12_0, ext_zhinx),
     ISA_EXT_DATA_ENTRY(zhinxmin, true, PRIV_VERSION_1_12_0, ext_zhinxmin),
+    ISA_EXT_DATA_ENTRY(sstc, true, PRIV_VERSION_1_12_0, ext_sstc),
     ISA_EXT_DATA_ENTRY(svinval, true, PRIV_VERSION_1_12_0, ext_svinval),
     ISA_EXT_DATA_ENTRY(svnapot, true, PRIV_VERSION_1_12_0, ext_svnapot),
     ISA_EXT_DATA_ENTRY(svpbmt, true, PRIV_VERSION_1_12_0, ext_svpbmt),
@@ -675,6 +677,13 @@  static void riscv_cpu_realize(DeviceState *dev, Error **errp)
 
     set_resetvec(env, cpu->cfg.resetvec);
 
+#ifndef CONFIG_USER_ONLY
+    if (cpu->cfg.ext_sstc) {
+        riscv_timer_init(cpu);
+    }
+#endif /* CONFIG_USER_ONLY */
+
+
     /* Validate that MISA_MXL is set properly. */
     switch (env->misa_mxl_max) {
 #ifdef TARGET_RISCV64
@@ -968,7 +977,9 @@  static void riscv_cpu_init(Object *obj)
 #ifndef CONFIG_USER_ONLY
     qdev_init_gpio_in(DEVICE(cpu), riscv_cpu_set_irq,
                       IRQ_LOCAL_MAX + IRQ_LOCAL_GUEST_MAX);
+
 #endif /* CONFIG_USER_ONLY */
+
 }
 
 static Property riscv_cpu_extensions[] = {
@@ -995,6 +1006,7 @@  static Property riscv_cpu_extensions[] = {
     DEFINE_PROP_BOOL("Zve64f", RISCVCPU, cfg.ext_zve64f, false),
     DEFINE_PROP_BOOL("mmu", RISCVCPU, cfg.mmu, true),
     DEFINE_PROP_BOOL("pmp", RISCVCPU, cfg.pmp, true),
+    DEFINE_PROP_BOOL("sstc", RISCVCPU, cfg.ext_sstc, true),
 
     DEFINE_PROP_STRING("priv_spec", RISCVCPU, cfg.priv_spec),
     DEFINE_PROP_STRING("vext_spec", RISCVCPU, cfg.vext_spec),
diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
index 0fae1569945c..4cda2905661e 100644
--- a/target/riscv/cpu.h
+++ b/target/riscv/cpu.h
@@ -309,6 +309,9 @@  struct CPUArchState {
     uint64_t mfromhost;
     uint64_t mtohost;
 
+    /* Sstc CSRs */
+    uint64_t stimecmp;
+
     /* physical memory protection */
     pmp_table_t pmp_state;
     target_ulong mseccfg;
@@ -362,6 +365,7 @@  struct CPUArchState {
     float_status fp_status;
 
     /* Fields from here on are preserved across CPU reset. */
+    QEMUTimer *stimer; /* Internal timer for S-mode interrupt */
 
     hwaddr kernel_addr;
     hwaddr fdt_addr;
@@ -425,6 +429,7 @@  struct RISCVCPUConfig {
     bool ext_ifencei;
     bool ext_icsr;
     bool ext_zihintpause;
+    bool ext_sstc;
     bool ext_svinval;
     bool ext_svnapot;
     bool ext_svpbmt;
diff --git a/target/riscv/cpu_bits.h b/target/riscv/cpu_bits.h
index 6be5a9e9f046..ac17cf1515c0 100644
--- a/target/riscv/cpu_bits.h
+++ b/target/riscv/cpu_bits.h
@@ -206,6 +206,10 @@ 
 #define CSR_STVAL           0x143
 #define CSR_SIP             0x144
 
+/* Sstc supervisor CSRs */
+#define CSR_STIMECMP        0x14D
+#define CSR_STIMECMPH       0x15D
+
 /* Supervisor Protection and Translation */
 #define CSR_SPTBR           0x180
 #define CSR_SATP            0x180
diff --git a/target/riscv/csr.c b/target/riscv/csr.c
index 0fb042b2fd0f..b71e2509b64f 100644
--- a/target/riscv/csr.c
+++ b/target/riscv/csr.c
@@ -22,6 +22,7 @@ 
 #include "qemu/timer.h"
 #include "cpu.h"
 #include "pmu.h"
+#include "time_helper.h"
 #include "qemu/main-loop.h"
 #include "exec/exec-all.h"
 #include "sysemu/cpu-timers.h"
@@ -803,6 +804,76 @@  static RISCVException read_timeh(CPURISCVState *env, int csrno,
     return RISCV_EXCP_NONE;
 }
 
+static RISCVException sstc(CPURISCVState *env, int csrno)
+{
+    CPUState *cs = env_cpu(env);
+    RISCVCPU *cpu = RISCV_CPU(cs);
+
+    if (!cpu->cfg.ext_sstc || !env->rdtime_fn) {
+        return RISCV_EXCP_ILLEGAL_INST;
+    }
+
+    if (env->priv == PRV_M) {
+        return RISCV_EXCP_NONE;
+    }
+
+    if (env->priv != PRV_S) {
+        return RISCV_EXCP_ILLEGAL_INST;
+    }
+
+    /*
+     * No need of separate function for rv32 as menvcfg stores both menvcfg
+     * menvcfgh for RV32.
+     */
+    if (!(get_field(env->mcounteren, COUNTEREN_TM) &&
+          get_field(env->menvcfg, MENVCFG_STCE))) {
+        return RISCV_EXCP_ILLEGAL_INST;
+    }
+
+    return RISCV_EXCP_NONE;
+}
+
+static RISCVException read_stimecmp(CPURISCVState *env, int csrno,
+                                    target_ulong *val)
+{
+    *val = env->stimecmp;
+    return RISCV_EXCP_NONE;
+}
+
+static RISCVException read_stimecmph(CPURISCVState *env, int csrno,
+                                    target_ulong *val)
+{
+    *val = env->stimecmp >> 32;
+    return RISCV_EXCP_NONE;
+}
+
+static RISCVException write_stimecmp(CPURISCVState *env, int csrno,
+                                    target_ulong val)
+{
+    RISCVCPU *cpu = env_archcpu(env);
+
+    if (riscv_cpu_mxl(env) == MXL_RV32) {
+        env->stimecmp = deposit64(env->stimecmp, 0, 32, (uint64_t)val);
+    } else {
+        env->stimecmp = val;
+    }
+
+    riscv_timer_write_timecmp(cpu, env->stimer, env->stimecmp, 0, MIP_STIP);
+
+    return RISCV_EXCP_NONE;
+}
+
+static RISCVException write_stimecmph(CPURISCVState *env, int csrno,
+                                    target_ulong val)
+{
+    RISCVCPU *cpu = env_archcpu(env);
+
+    env->stimecmp = deposit64(env->stimecmp, 32, 32, (uint64_t)val);
+    riscv_timer_write_timecmp(cpu, env->stimer, env->stimecmp, 0, MIP_STIP);
+
+    return RISCV_EXCP_NONE;
+}
+
 /* Machine constants */
 
 #define M_MODE_INTERRUPTS  ((uint64_t)(MIP_MSIP | MIP_MTIP | MIP_MEIP))
@@ -1719,6 +1790,12 @@  static RISCVException rmw_mip64(CPURISCVState *env, int csrno,
         new_val |= env->external_seip * MIP_SEIP;
     }
 
+    if (cpu->cfg.ext_sstc && (env->priv == PRV_M) &&
+        get_field(env->menvcfg, MENVCFG_STCE)) {
+        /* sstc extension forbids STIP & VSTIP to be writeable in mip */
+        mask = mask & ~(MIP_STIP | MIP_VSTIP);
+    }
+
     if (mask) {
         old_mip = riscv_cpu_update_mip(cpu, mask, (new_val & mask));
     } else {
@@ -3584,6 +3661,10 @@  riscv_csr_operations csr_ops[CSR_TABLE_SIZE] = {
     [CSR_SCAUSE]   = { "scause",   smode, read_scause,   write_scause   },
     [CSR_STVAL]    = { "stval",    smode, read_stval,    write_stval    },
     [CSR_SIP]      = { "sip",      smode, NULL,    NULL, rmw_sip        },
+    [CSR_STIMECMP] = { "stimecmp", sstc, read_stimecmp, write_stimecmp,
+                                          .min_priv_ver = PRIV_VERSION_1_12_0 },
+    [CSR_STIMECMPH] = { "stimecmph", sstc, read_stimecmph, write_stimecmph,
+                                          .min_priv_ver = PRIV_VERSION_1_12_0 },
 
     /* Supervisor Protection and Translation */
     [CSR_SATP]     = { "satp",     smode, read_satp,     write_satp     },
diff --git a/target/riscv/machine.c b/target/riscv/machine.c
index b508b042cb73..622fface484e 100644
--- a/target/riscv/machine.c
+++ b/target/riscv/machine.c
@@ -359,6 +359,7 @@  const VMStateDescription vmstate_riscv_cpu = {
         VMSTATE_UINTTL(env.mscratch, RISCVCPU),
         VMSTATE_UINT64(env.mfromhost, RISCVCPU),
         VMSTATE_UINT64(env.mtohost, RISCVCPU),
+        VMSTATE_UINT64(env.stimecmp, RISCVCPU),
 
         VMSTATE_END_OF_LIST()
     },
diff --git a/target/riscv/meson.build b/target/riscv/meson.build
index 2c1975e72c4e..24893c614ee4 100644
--- a/target/riscv/meson.build
+++ b/target/riscv/meson.build
@@ -31,7 +31,8 @@  riscv_softmmu_ss.add(files(
   'debug.c',
   'monitor.c',
   'machine.c',
-  'pmu.c'
+  'pmu.c',
+  'time_helper.c'
 ))
 
 target_arch += {'riscv': riscv_ss}
diff --git a/target/riscv/time_helper.c b/target/riscv/time_helper.c
new file mode 100644
index 000000000000..f3fb5eac7b7b
--- /dev/null
+++ b/target/riscv/time_helper.c
@@ -0,0 +1,98 @@ 
+/*
+ * RISC-V timer helper implementation.
+ *
+ * Copyright (c) 2022 Rivos Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2 or later, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "qemu/osdep.h"
+#include "qemu/log.h"
+#include "cpu_bits.h"
+#include "time_helper.h"
+#include "hw/intc/riscv_aclint.h"
+
+static void riscv_stimer_cb(void *opaque)
+{
+    RISCVCPU *cpu = opaque;
+    riscv_cpu_update_mip(cpu, MIP_STIP, BOOL_TO_MASK(1));
+}
+
+/*
+ * Called when timecmp is written to update the QEMU timer or immediately
+ * trigger timer interrupt if mtimecmp <= current timer value.
+ */
+void riscv_timer_write_timecmp(RISCVCPU *cpu, QEMUTimer *timer,
+                               uint64_t timecmp, uint64_t delta,
+                               uint32_t timer_irq)
+{
+    uint64_t diff, ns_diff, next;
+    CPURISCVState *env = &cpu->env;
+    RISCVAclintMTimerState *mtimer = env->rdtime_fn_arg;
+    uint32_t timebase_freq = mtimer->timebase_freq;
+    uint64_t rtc_r = env->rdtime_fn(env->rdtime_fn_arg) + delta;
+
+    if (timecmp <= rtc_r) {
+        /*
+         * If we're setting an stimecmp value in the "past",
+         * immediately raise the timer interrupt
+         */
+        riscv_cpu_update_mip(cpu, timer_irq, BOOL_TO_MASK(1));
+        return;
+    }
+
+    /* Clear the [V]STIP bit in mip */
+    riscv_cpu_update_mip(cpu, timer_irq, BOOL_TO_MASK(0));
+
+    /* otherwise, set up the future timer interrupt */
+    diff = timecmp - rtc_r;
+    /* back to ns (note args switched in muldiv64) */
+    ns_diff = muldiv64(diff, NANOSECONDS_PER_SECOND, timebase_freq);
+
+    /*
+     * check if ns_diff overflowed and check if the addition would potentially
+     * overflow
+     */
+    if ((NANOSECONDS_PER_SECOND > timebase_freq && ns_diff < diff) ||
+        ns_diff > INT64_MAX) {
+        next = INT64_MAX;
+    } else {
+        /*
+         * as it is very unlikely qemu_clock_get_ns will return a value
+         * greater than INT64_MAX, no additional check is needed for an
+         * unsigned integer overflow.
+         */
+        next = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + ns_diff;
+        /*
+         * if ns_diff is INT64_MAX next may still be outside the range
+         * of a signed integer.
+         */
+        next = MIN(next, INT64_MAX);
+    }
+
+    timer_mod(timer, next);
+}
+
+void riscv_timer_init(RISCVCPU *cpu)
+{
+    CPURISCVState *env;
+
+    if (!cpu) {
+        return;
+    }
+
+    env = &cpu->env;
+    env->stimer = timer_new_ns(QEMU_CLOCK_VIRTUAL, &riscv_stimer_cb, cpu);
+    env->stimecmp = 0;
+
+}
diff --git a/target/riscv/time_helper.h b/target/riscv/time_helper.h
new file mode 100644
index 000000000000..7b3cdcc35020
--- /dev/null
+++ b/target/riscv/time_helper.h
@@ -0,0 +1,30 @@ 
+/*
+ * RISC-V timer header file.
+ *
+ * Copyright (c) 2022 Rivos Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2 or later, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef RISCV_TIME_HELPER_H
+#define RISCV_TIME_HELPER_H
+
+#include "cpu.h"
+#include "qemu/timer.h"
+
+void riscv_timer_write_timecmp(RISCVCPU *cpu, QEMUTimer *timer,
+                               uint64_t timecmp, uint64_t delta,
+                               uint32_t timer_irq);
+void riscv_timer_init(RISCVCPU *cpu);
+
+#endif