target/riscv: Extend the SIP CSR to support virtulisation

Signed-off-by: NAlistair Francis <alistair.francis@wdc.com>
Reviewed-by: NPalmer Dabbelt <palmerdabbelt@google.com>
Signed-off-by: NPalmer Dabbelt <palmerdabbelt@google.com>

target/riscv/csr.c

@@ -743,8 +743,19 @@ static int write_sbadaddr(CPURISCVState *env, int csrno, target_ulong val)
 static int rmw_sip(CPURISCVState *env, int csrno, target_ulong *ret_value,
                    target_ulong new_value, target_ulong write_mask)
 {
-    int ret = rmw_mip(env, CSR_MSTATUS, ret_value, new_value,
+    int ret;
+
+    if (riscv_cpu_virt_enabled(env)) {
+        /* Shift the new values to line up with the VS bits */
+        ret = rmw_mip(env, CSR_MSTATUS, ret_value, new_value << 1,
+                      (write_mask & sip_writable_mask) << 1 & env->mideleg);
+        ret &= vsip_writable_mask;
+        ret >>= 1;
+    } else {
+        ret = rmw_mip(env, CSR_MSTATUS, ret_value, new_value,
                       write_mask & env->mideleg & sip_writable_mask);
+    }
+
     *ret_value &= env->mideleg;
     return ret;
 }