diff --git a/target/riscv/csr.c b/target/riscv/csr.c
index 9264db6..a3e0e57 100644
--- a/target/riscv/csr.c
+++ b/target/riscv/csr.c
@@ -3360,7 +3360,7 @@
     if (!check_pmp_reg_index(env, reg_index)) {
         return RISCV_EXCP_ILLEGAL_INST;
     }
-    *val = pmpcfg_csr_read(env, csrno - CSR_PMPCFG0);
+    *val = pmpcfg_csr_read(env, reg_index);
     return RISCV_EXCP_NONE;
 }
 
@@ -3372,7 +3372,7 @@
     if (!check_pmp_reg_index(env, reg_index)) {
         return RISCV_EXCP_ILLEGAL_INST;
     }
-    pmpcfg_csr_write(env, csrno - CSR_PMPCFG0, val);
+    pmpcfg_csr_write(env, reg_index, val);
     return RISCV_EXCP_NONE;
 }