target/riscv: generate virtual instruction exception

This patch adds a mechanism to generate a virtual instruction
instruction exception instead of an illegal instruction exception
during instruction decode when virt is enabled.

Signed-off-by: Mayuresh Chitale <mchitale@ventanamicro.com>
Reviewed-by: Weiwei Li <liweiwei@iscas.ac.cn>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-Id: <20221016124726.102129-4-mchitale@ventanamicro.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

diff --git a/target/riscv/translate.c b/target/riscv/translate.c
index db123da5ec1b89a323e9e7417404a91e8f1a6a20..8b0bd38bb2da2b8db489a878f530b36cb3dd3758 100644 (file)
--- a/target/riscv/translate.c
+++ b/target/riscv/translate.c
@@ -76,6 +76,7 @@ typedef struct DisasContext {
        to reset this known value.  */
     int frm;
     RISCVMXL ol;
+    bool virt_inst_excp;
     bool virt_enabled;
     const RISCVCPUConfig *cfg_ptr;
     bool hlsx;
@@ -243,7 +244,11 @@ static void gen_exception_illegal(DisasContext *ctx)
 {
     tcg_gen_st_i32(tcg_constant_i32(ctx->opcode), cpu_env,
                    offsetof(CPURISCVState, bins));
-    generate_exception(ctx, RISCV_EXCP_ILLEGAL_INST);
+    if (ctx->virt_inst_excp) {
+        generate_exception(ctx, RISCV_EXCP_VIRT_INSTRUCTION_FAULT);
+    } else {
+        generate_exception(ctx, RISCV_EXCP_ILLEGAL_INST);
+    }
 }
 
 static void gen_exception_inst_addr_mis(DisasContext *ctx)
@@ -1062,6 +1067,7 @@ static void decode_opc(CPURISCVState *env, DisasContext *ctx, uint16_t opcode)
         { has_XVentanaCondOps_p,  decode_XVentanaCodeOps },
     };
 
+    ctx->virt_inst_excp = false;
     /* Check for compressed insn */
     if (insn_len(opcode) == 2) {
         if (!has_ext(ctx, RVC)) {