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 <ati...@rivosinc.com> --- target/riscv/cpu.c | 7 +++ target/riscv/cpu.h | 5 ++ target/riscv/cpu_bits.h | 4 ++ target/riscv/csr.c | 84 +++++++++++++++++++++++++++++++++ target/riscv/machine.c | 1 + target/riscv/meson.build | 3 +- target/riscv/time_helper.c | 97 ++++++++++++++++++++++++++++++++++++++ target/riscv/time_helper.h | 30 ++++++++++++ 8 files changed, 230 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 5d24a191c059..c609ed3c5834 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" @@ -751,6 +752,10 @@ static void riscv_cpu_init(Object *obj) qdev_init_gpio_in(DEVICE(cpu), riscv_cpu_set_irq, IRQ_LOCAL_MAX + IRQ_LOCAL_GUEST_MAX); #endif /* CONFIG_USER_ONLY */ + + if (cpu->cfg.ext_sstc) { + riscv_timer_init(cpu); + } } static Property riscv_cpu_properties[] = { @@ -776,6 +781,7 @@ static Property riscv_cpu_properties[] = { 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), @@ -898,6 +904,7 @@ static void riscv_isa_string_ext(RISCVCPU *cpu, char **isa_str, int max_str_len) { "svpbmt", cpu->cfg.ext_svpbmt }, { "svinval", cpu->cfg.ext_svinval }, { "svnapot", cpu->cfg.ext_svnapot }, + { "sstc", cpu->cfg.ext_sstc }, }; for (i = 0; i < ARRAY_SIZE(isa_edata_arr); i++) { diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h index 94234c59ffa8..fa90ab9f473b 100644 --- a/target/riscv/cpu.h +++ b/target/riscv/cpu.h @@ -267,6 +267,9 @@ struct CPURISCVState { uint64_t mtohost; uint64_t mtimecmp; + /* Sstc CSRs */ + uint64_t stimecmp; + /* physical memory protection */ pmp_table_t pmp_state; target_ulong mseccfg; @@ -317,6 +320,7 @@ struct CPURISCVState { /* Fields from here on are preserved across CPU reset. */ QEMUTimer *mtimer; /* Internal timer for M-mode interrupt */ + QEMUTimer *stimer; /* Internal timer for S-mode interrupt */ hwaddr kernel_addr; hwaddr fdt_addr; @@ -371,6 +375,7 @@ struct RISCVCPUConfig { bool ext_svinval; bool ext_svnapot; bool ext_svpbmt; + bool ext_sstc; bool ext_zfh; bool ext_zfhmin; bool ext_zve32f; diff --git a/target/riscv/cpu_bits.h b/target/riscv/cpu_bits.h index bb47cf7e77a2..34496ac5aa80 100644 --- a/target/riscv/cpu_bits.h +++ b/target/riscv/cpu_bits.h @@ -212,6 +212,10 @@ #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 b16881615997..ad7a8db2dd0d 100644 --- a/target/riscv/csr.c +++ b/target/riscv/csr.c @@ -20,8 +20,10 @@ #include "qemu/osdep.h" #include "qemu/log.h" #include "cpu.h" +#include "time_helper.h" #include "qemu/main-loop.h" #include "exec/exec-all.h" +#include "hw/intc/riscv_aclint.h" /* CSR function table public API */ void riscv_get_csr_ops(int csrno, riscv_csr_operations *ops) @@ -519,6 +521,78 @@ 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) { + uint64_t stimecmp_hi = env->stimecmp >> 32; + env->stimecmp = (stimecmp_hi << 32) | (val & 0xFFFFFFFF); + } 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); + uint64_t timer_val = 0; + + timer_val = (uint64_t)val << 32 | (env->stimecmp & 0xFFFFFFFF); + env->stimecmp = timer_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)) @@ -1485,6 +1559,12 @@ static RISCVException rmw_mip64(CPURISCVState *env, int csrno, uint64_t old_mip, mask = wr_mask & delegable_ints & ~env->miclaim; uint32_t gin; + 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 { @@ -3265,6 +3345,10 @@ 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, + NULL, NULL, NULL, PRIV_VERSION_1_12_0}, + [CSR_STIMECMPH] = { "stimecmph", sstc, read_stimecmph, write_stimecmph, + NULL, NULL, NULL, 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 be3022082a46..2f2e16c72607 100644 --- a/target/riscv/machine.c +++ b/target/riscv/machine.c @@ -304,6 +304,7 @@ const VMStateDescription vmstate_riscv_cpu = { VMSTATE_UINT64(env.mfromhost, RISCVCPU), VMSTATE_UINT64(env.mtohost, RISCVCPU), VMSTATE_UINT64(env.mtimecmp, RISCVCPU), + VMSTATE_UINT64(env.stimecmp, RISCVCPU), VMSTATE_END_OF_LIST() }, diff --git a/target/riscv/meson.build b/target/riscv/meson.build index 91f0ac32ff3d..b51d9d5858cc 100644 --- a/target/riscv/meson.build +++ b/target/riscv/meson.build @@ -19,7 +19,8 @@ riscv_ss.add(files( 'vector_helper.c', 'bitmanip_helper.c', 'translate.c', - 'm128_helper.c' + 'm128_helper.c', + 'time_helper.c' )) riscv_ss.add(when: 'CONFIG_KVM', if_true: files('kvm.c'), if_false: files('kvm-stub.c')) diff --git a/target/riscv/time_helper.c b/target/riscv/time_helper.c new file mode 100644 index 000000000000..105a051caace --- /dev/null +++ b/target/riscv/time_helper.c @@ -0,0 +1,97 @@ +/* + * 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; + uint32_t timebase_freq = env->rdtime_fn_arg; + uint64_t rtc_r = env->rdtime_fn(timebase_freq) + 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 -- 2.30.2