target/riscv: Fix csr number based privilege checking

When hypervisor and VS CSRs are accessed from VS-mode or VU-mode,
the riscv_csrrw_check() function should generate virtual instruction
trap instead illegal instruction trap.

Fixes: 0a42f4c (" target/riscv: Fix CSR perm checking for HS mode")
Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Frank Chang <frank.chang@sifive.com>
Message-Id: <20220511144528.393530-2-apatel@ventanamicro.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

target/riscv/csr.c

@@ -3139,7 +3139,7 @@ static inline RISCVException riscv_csrrw_check(CPURISCVState *env,
     int read_only = get_field(csrno, 0xC00) == 3;
     int csr_min_priv = csr_ops[csrno].min_priv_ver;
 #if !defined(CONFIG_USER_ONLY)
-    int effective_priv = env->priv;
+    int csr_priv, effective_priv = env->priv;
 
     if (riscv_has_ext(env, RVH) && env->priv == PRV_S) {
         /*
@@ -3152,7 +3152,11 @@ static inline RISCVException riscv_csrrw_check(CPURISCVState *env,
         effective_priv++;
     }
 
-    if (!env->debugger && (effective_priv < get_field(csrno, 0x300))) {
+    csr_priv = get_field(csrno, 0x300);
+    if (!env->debugger && (effective_priv < csr_priv)) {
+        if (csr_priv == (PRV_S + 1) && riscv_cpu_virt_enabled(env)) {
+            return RISCV_EXCP_VIRT_INSTRUCTION_FAULT;
+        }
         return RISCV_EXCP_ILLEGAL_INST;
     }
 #endif