[PATCH] target/ppc: Add lower bound check for watchdogNumber

Add missing lower bound check for H_WATCHDOG H_CALL's watchdogNumber parameter
as per PAPR documentation ver 12.10.00 section 14.15.5 'H_WATCHDOG'.

Closes : https://gitlab.com/qemu-project/qemu/-/work_items/3600

Signed-off-by: Chinmay Rath <[email protected]>
---
 hw/watchdog/spapr_watchdog.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/hw/watchdog/spapr_watchdog.c b/hw/watchdog/spapr_watchdog.c
index 5b3f50de3a..5d7478e833 100644
--- a/hw/watchdog/spapr_watchdog.c
+++ b/hw/watchdog/spapr_watchdog.c
@@ -145,7 +145,7 @@ static target_ulong h_watchdog(PowerPCCPU *cpu,
 
     switch (operation) {
     case PSERIES_WDTF_OP_START:
-        if (watchdogNumber > ARRAY_SIZE(spapr->wds)) {
+        if (watchdogNumber < 1 || watchdogNumber > ARRAY_SIZE(spapr->wds)) {
             return H_P2;
         }
         if (timeoutInMs <= WDT_MIN_TIMEOUT) {
@@ -170,7 +170,8 @@ static target_ulong h_watchdog(PowerPCCPU *cpu,
     case PSERIES_WDTF_OP_STOP:
         if (watchdogNumber == PSERIES_WDT_STOP_ALL) {
             ret = watchdog_stop_all(spapr);
-        } else if (watchdogNumber <= ARRAY_SIZE(spapr->wds)) {
+        } else if (watchdogNumber > 0 &&
+                   watchdogNumber <= ARRAY_SIZE(spapr->wds)) {
             ret = watchdog_stop(watchdogNumber,
                                 &spapr->wds[watchdogNumber - 1]);
         } else {
@@ -184,7 +185,7 @@ static target_ulong h_watchdog(PowerPCCPU *cpu,
         trace_spapr_watchdog_query(args[0]);
         break;
     case PSERIES_WDTF_OP_QUERY_LPM:
-        if (watchdogNumber > ARRAY_SIZE(spapr->wds)) {
+        if (watchdogNumber < 1 || watchdogNumber > ARRAY_SIZE(spapr->wds)) {
             return H_P2;
         }
         args[0] = PSERIES_WDTQL_QUERY_NOT_STOPPED;
-- 
2.55.0