target/riscv: Add the checking into stimecmp write function.

Preparation commit to let aclint timer to use stimecmp write function.
Aclint timer doesn't call sstc() predicate so we need to check inside
the stimecmp write function.

Signed-off-by: Jim Shu <jim.shu@sifive.com>
Acked-by: Alistair Francis <alistair.francis@wdc.com>
Message-ID: <20250519143518.11086-2-jim.shu@sifive.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

1 files changed, 17 insertions, 2 deletions

diff --git a/target/riscv/time_helper.c b/target/riscv/time_helper.c
index bc0d9a0c4c..aebf0798d0 100644
--- a/target/riscv/time_helper.c
+++ b/target/riscv/time_helper.c
@@ -46,8 +46,23 @@ void riscv_timer_write_timecmp(CPURISCVState *env, QEMUTimer *timer,
 {
     uint64_t diff, ns_diff, next;
     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;
+    uint32_t timebase_freq;
+    uint64_t rtc_r;
+
+    if (!riscv_cpu_cfg(env)->ext_sstc || !env->rdtime_fn ||
+        !env->rdtime_fn_arg || !get_field(env->menvcfg, MENVCFG_STCE)) {
+        /* S/VS Timer IRQ depends on sstc extension, rdtime_fn(), and STCE. */
+        return;
+    }
+
+    if (timer_irq == MIP_VSTIP &&
+        (!riscv_has_ext(env, RVH) || !get_field(env->henvcfg, HENVCFG_STCE))) {
+        /* VS Timer IRQ also depends on RVH and henvcfg.STCE. */
+        return;
+    }
+
+    timebase_freq = mtimer->timebase_freq;
+    rtc_r = env->rdtime_fn(env->rdtime_fn_arg) + delta;
 
     if (timecmp <= rtc_r) {
         /*