diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 9353268cc1..bd0c99859d 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -9058,6 +9058,8 @@ static int do_getdents64(abi_long dirfd, abi_long arg2, abi_long count)
 #define     RISCV_HWPROBE_MISALIGNED_UNSUPPORTED (4 << 0)
 #define     RISCV_HWPROBE_MISALIGNED_MASK        (7 << 0)
 
+#define RISCV_HWPROBE_KEY_ZICBOZ_BLOCK_SIZE 6
+
 struct riscv_hwprobe {
     abi_llong  key;
     abi_ullong value;
@@ -9102,6 +9104,10 @@ static void risc_hwprobe_fill_pairs(CPURISCVState *env,
         case RISCV_HWPROBE_KEY_CPUPERF_0:
             __put_user(RISCV_HWPROBE_MISALIGNED_FAST, &pair->value);
             break;
+        case RISCV_HWPROBE_KEY_ZICBOZ_BLOCK_SIZE:
+            value = cfg->ext_icboz ? cfg->cboz_blocksize : 0;
+            __put_user(value, &pair->value);
+            break;
         default:
             __put_user(-1, &pair->key);
             break;