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[PATCH] target/riscv: Fix VS mode hypervisor CSR access


From: Dylan Reid
Subject: [PATCH] target/riscv: Fix VS mode hypervisor CSR access
Date: Fri, 6 May 2022 16:54:57 +0000

VS mode access to hypervisor CSRs should generate virtual, not illegal,
instruction exceptions.

Don't return early and indicate an illegal instruction exception when
accessing a hypervisor CSR from VS mode. Instead, fall through to the
`hmode` predicate to return the correct virtual instruction exception.

Signed-off-by: Dylan Reid <dgreid@rivosinc.com>
---
 target/riscv/csr.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/target/riscv/csr.c b/target/riscv/csr.c
index 3500e07f92..4ea7df02c9 100644
--- a/target/riscv/csr.c
+++ b/target/riscv/csr.c
@@ -3141,13 +3141,13 @@ static inline RISCVException 
riscv_csrrw_check(CPURISCVState *env,
 #if !defined(CONFIG_USER_ONLY)
     int effective_priv = env->priv;
 
-    if (riscv_has_ext(env, RVH) &&
-        env->priv == PRV_S &&
-        !riscv_cpu_virt_enabled(env)) {
+    if (riscv_has_ext(env, RVH) && env->priv == PRV_S) {
         /*
-         * We are in S mode without virtualisation, therefore we are in HS 
Mode.
+         * We are in either HS or VS mode.
          * Add 1 to the effective privledge level to allow us to access the
-         * Hypervisor CSRs.
+         * Hypervisor CSRs. The `hmode` predicate will determine if access
+         * should be allowed(HS) or if a virtual instruction exception should 
be
+         * raised(VS).
          */
         effective_priv++;
     }
-- 
2.30.2




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