[PATCH v10 3/5] target/riscv: generate virtual instruction exception

[Mayuresh Chitale]

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 <mchit...@ventanamicro.com>
---
 target/riscv/translate.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/target/riscv/translate.c b/target/riscv/translate.c
index db123da5ec..6926b639de 100644
--- 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)
@@ -1067,6 +1072,7 @@ static void decode_opc(CPURISCVState *env, DisasContext 
*ctx, uint16_t opcode)
         if (!has_ext(ctx, RVC)) {
             gen_exception_illegal(ctx);
         } else {
+            ctx->virt_inst_excp = false;
             ctx->opcode = opcode;
             ctx->pc_succ_insn = ctx->base.pc_next + 2;
             if (decode_insn16(ctx, opcode)) {
@@ -1078,6 +1084,7 @@ static void decode_opc(CPURISCVState *env, DisasContext 
*ctx, uint16_t opcode)
         opcode32 = deposit32(opcode32, 16, 16,
                              translator_lduw(env, &ctx->base,
                                              ctx->base.pc_next + 2));
+        ctx->virt_inst_excp = false;
         ctx->opcode = opcode32;
         ctx->pc_succ_insn = ctx->base.pc_next + 4;
 
-- 
2.25.1