riscv_csr: Set OPST=ES16 to indicate success

Previously, the OPST field was set to BIST (0), indicating that a
Built-In Self-Test is running.

Author: spholz

src/riscv_csr.c

@@ -166,7 +166,7 @@ static inline bool riscv_csr_seed(rvvm_hart_t* vm, rvvm_uxlen_t* dest)
     if (riscv_csr_seed_enabled(vm)) {
         uint16_t seed = 0;
         rvvm_randombytes(&seed, sizeof(seed));
-        return riscv_csr_const(dest, seed);
+        return riscv_csr_const(dest, seed | CSR_SEED_OPST_ES16);
     }
     return false;
 }

src/riscv_csr.h

@@ -297,6 +297,8 @@ file, You can obtain one at https://mozilla.org/MPL/2.0/.
 #define CSR_COUNTEREN_TM   0x2U
 #define CSR_COUNTEREN_IR   0x4U
 
+#define CSR_SEED_OPST_ES16 (3ULL << 30)
+
 /*
  * CSR Masks (For WARL behavior of CSRs)
  */