From 5de124538b618c864508868eae505e77149649b7 Mon Sep 17 00:00:00 2001 From: Weiwei Li Date: Mon, 18 Jul 2022 21:09:55 +0800 Subject: [PATCH] target/riscv: Simplify the check in hmode to reuse the check in riscv_csrrw_check Just add 1 to the effective privledge level when in HS mode, then reuse the check of 'effective_priv < csr_priv' in riscv_csrrw_check to replace the privilege level related check in hmode. Then, hmode will only check whether H extension is supported. When accessing Hypervior CSRs: 1) If accessing from M privilege level, the check of 'effective_priv< csr_priv' passes, returns hmode(...) which will return RISCV_EXCP_ILLEGAL_INST when H extension is not supported and return RISCV_EXCP_NONE otherwise. 2) If accessing from HS privilege level, effective_priv will add 1, the check passes and also returns hmode(...) too. 3) If accessing from VS/VU privilege level, the check fails, and returns RISCV_EXCP_VIRT_INSTRUCTION_FAULT 4) If accessing from U privilege level, the check fails, and returns RISCV_EXCP_ILLEGAL_INST Signed-off-by: Weiwei Li Signed-off-by: Junqiang Wang Reviewed-by: Alistair Francis Reviewed-by: Andrew Jones Message-Id: <20220718130955.11899-7-liweiwei@iscas.ac.cn> Signed-off-by: Alistair Francis --- target/riscv/csr.c | 18 +++++------------- 1 file changed, 5 insertions(+), 13 deletions(-) diff --git a/target/riscv/csr.c b/target/riscv/csr.c index cf15aa67b7..0fb042b2fd 100644 --- a/target/riscv/csr.c +++ b/target/riscv/csr.c @@ -312,13 +312,7 @@ static int aia_smode32(CPURISCVState *env, int csrno) static RISCVException hmode(CPURISCVState *env, int csrno) { if (riscv_has_ext(env, RVH)) { - /* Hypervisor extension is supported */ - if ((env->priv == PRV_S && !riscv_cpu_virt_enabled(env)) || - env->priv == PRV_M) { - return RISCV_EXCP_NONE; - } else { - return RISCV_EXCP_VIRT_INSTRUCTION_FAULT; - } + return RISCV_EXCP_NONE; } return RISCV_EXCP_ILLEGAL_INST; @@ -3279,13 +3273,11 @@ static inline RISCVException riscv_csrrw_check(CPURISCVState *env, #if !defined(CONFIG_USER_ONLY) int csr_priv, effective_priv = env->priv; - if (riscv_has_ext(env, RVH) && env->priv == PRV_S) { + if (riscv_has_ext(env, RVH) && env->priv == PRV_S && + !riscv_cpu_virt_enabled(env)) { /* - * We are in either HS or VS mode. - * Add 1 to the effective privledge level to allow us to access the - * Hypervisor CSRs. The `hmode` predicate will determine if access - * should be allowed(HS) or if a virtual instruction exception should be - * raised(VS). + * We are in HS mode. Add 1 to the effective privledge level to + * allow us to access the Hypervisor CSRs. */ effective_priv++; }