[PATCH] target/riscv: fix vs() to return proper error code

[frank . chang]

From: Frank Chang <frank.ch...@sifive.com>

vs() should return -RISCV_EXCP_ILLEGAL_INST instead of -1 if rvv feature
is not enabled.

If -1 is returned, exception will be raised and cs->exception_index will
be set to the negative return value. The exception will then be treated
as an instruction access fault instead of illegal instruction fault.

Signed-off-by: Frank Chang <frank.ch...@sifive.com>
---
 target/riscv/csr.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/target/riscv/csr.c b/target/riscv/csr.c
index fd2e6363f39..d2ae73e4a08 100644
--- a/target/riscv/csr.c
+++ b/target/riscv/csr.c
@@ -54,7 +54,7 @@ static int vs(CPURISCVState *env, int csrno)
     if (env->misa & RVV) {
         return 0;
     }
-    return -1;
+    return -RISCV_EXCP_ILLEGAL_INST;
 }
 
 static int ctr(CPURISCVState *env, int csrno)
-- 
2.17.1