[PATCH 4/5] target/riscv: No need to re-start QEMU timer when timecmp == UINT64_MAX

[Anup Patel]

The time CSR will wrap-around immediately after reaching UINT64_MAX
so we don't need to re-start QEMU timer when timecmp == UINT64_MAX
in riscv_timer_write_timecmp().

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
---
 target/riscv/time_helper.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/target/riscv/time_helper.c b/target/riscv/time_helper.c
index 4fb2a471a9..1ee9f94813 100644
--- a/target/riscv/time_helper.c
+++ b/target/riscv/time_helper.c
@@ -72,6 +72,14 @@ void riscv_timer_write_timecmp(RISCVCPU *cpu, QEMUTimer 
*timer,
         riscv_cpu_update_mip(cpu, timer_irq, BOOL_TO_MASK(0));
     }
 
+    /*
+     * Don't re-start the QEMU timer when timecmp == UINT64_MAX because
+     * time CSR will wrap-around immediately after reaching UINT64_MAX.
+     */
+    if (timecmp == UINT64_MAX) {
+        return;
+    }
+
     /* otherwise, set up the future timer interrupt */
     diff = timecmp - rtc_r;
     /* back to ns (note args switched in muldiv64) */
-- 
2.34.1