[PATCH v6 2/6] target/riscv: hardwire mstatus.FS to zero when enable zfinx

[Weiwei Li]

Co-authored-by: ardxwe <ard...@gmail.com>
Signed-off-by: Weiwei Li <liwei...@iscas.ac.cn>
Signed-off-by: Junqiang Wang <wangjunqi...@iscas.ac.cn>
Reviewed-by: Alistair Francis <alistair.fran...@wdc.com>
---
 target/riscv/cpu_helper.c |  6 +++++-
 target/riscv/csr.c        | 25 ++++++++++++++++++++-----
 target/riscv/translate.c  |  4 ++++
 3 files changed, 29 insertions(+), 6 deletions(-)

diff --git a/target/riscv/cpu_helper.c b/target/riscv/cpu_helper.c
index 746335bfd6..1c60fb2e80 100644
--- a/target/riscv/cpu_helper.c
+++ b/target/riscv/cpu_helper.c
@@ -466,9 +466,13 @@ bool riscv_cpu_vector_enabled(CPURISCVState *env)
 
 void riscv_cpu_swap_hypervisor_regs(CPURISCVState *env)
 {
-    uint64_t mstatus_mask = MSTATUS_MXR | MSTATUS_SUM | MSTATUS_FS |
+    uint64_t mstatus_mask = MSTATUS_MXR | MSTATUS_SUM |
                             MSTATUS_SPP | MSTATUS_SPIE | MSTATUS_SIE |
                             MSTATUS64_UXL | MSTATUS_VS;
+
+    if (riscv_has_ext(env, RVF)) {
+        mstatus_mask |= MSTATUS_FS;
+    }
     bool current_virt = riscv_cpu_virt_enabled(env);
 
     g_assert(riscv_has_ext(env, RVH));
diff --git a/target/riscv/csr.c b/target/riscv/csr.c
index 387088a86c..93bba1ca1c 100644
--- a/target/riscv/csr.c
+++ b/target/riscv/csr.c
@@ -38,7 +38,8 @@ void riscv_set_csr_ops(int csrno, riscv_csr_operations *ops)
 static RISCVException fs(CPURISCVState *env, int csrno)
 {
 #if !defined(CONFIG_USER_ONLY)
-    if (!env->debugger && !riscv_cpu_fp_enabled(env)) {
+    if (!env->debugger && !riscv_cpu_fp_enabled(env) &&
+        !RISCV_CPU(env_cpu(env))->cfg.ext_zfinx) {
         return RISCV_EXCP_ILLEGAL_INST;
     }
 #endif
@@ -301,7 +302,9 @@ static RISCVException write_fflags(CPURISCVState *env, int 
csrno,
                                    target_ulong val)
 {
 #if !defined(CONFIG_USER_ONLY)
-    env->mstatus |= MSTATUS_FS;
+    if (riscv_has_ext(env, RVF)) {
+        env->mstatus |= MSTATUS_FS;
+    }
 #endif
     riscv_cpu_set_fflags(env, val & (FSR_AEXC >> FSR_AEXC_SHIFT));
     return RISCV_EXCP_NONE;
@@ -318,7 +321,9 @@ static RISCVException write_frm(CPURISCVState *env, int 
csrno,
                                 target_ulong val)
 {
 #if !defined(CONFIG_USER_ONLY)
-    env->mstatus |= MSTATUS_FS;
+    if (riscv_has_ext(env, RVF)) {
+        env->mstatus |= MSTATUS_FS;
+    }
 #endif
     env->frm = val & (FSR_RD >> FSR_RD_SHIFT);
     return RISCV_EXCP_NONE;
@@ -336,7 +341,9 @@ static RISCVException write_fcsr(CPURISCVState *env, int 
csrno,
                                  target_ulong val)
 {
 #if !defined(CONFIG_USER_ONLY)
-    env->mstatus |= MSTATUS_FS;
+    if (riscv_has_ext(env, RVF)) {
+        env->mstatus |= MSTATUS_FS;
+    }
 #endif
     env->frm = (val & FSR_RD) >> FSR_RD_SHIFT;
     riscv_cpu_set_fflags(env, (val & FSR_AEXC) >> FSR_AEXC_SHIFT);
@@ -652,10 +659,14 @@ static RISCVException write_mstatus(CPURISCVState *env, 
int csrno,
         tlb_flush(env_cpu(env));
     }
     mask = MSTATUS_SIE | MSTATUS_SPIE | MSTATUS_MIE | MSTATUS_MPIE |
-        MSTATUS_SPP | MSTATUS_FS | MSTATUS_MPRV | MSTATUS_SUM |
+        MSTATUS_SPP | MSTATUS_MPRV | MSTATUS_SUM |
         MSTATUS_MPP | MSTATUS_MXR | MSTATUS_TVM | MSTATUS_TSR |
         MSTATUS_TW | MSTATUS_VS;
 
+    if (riscv_has_ext(env, RVF)) {
+        mask |= MSTATUS_FS;
+    }
+
     if (xl != MXL_RV32 || env->debugger) {
         /*
          * RV32: MPV and GVA are not in mstatus. The current plan is to
@@ -787,6 +798,10 @@ static RISCVException write_misa(CPURISCVState *env, int 
csrno,
         return RISCV_EXCP_NONE;
     }
 
+    if (!(val & RVF)) {
+        env->mstatus &= ~MSTATUS_FS;
+    }
+
     /* flush translation cache */
     tb_flush(env_cpu(env));
     env->misa_ext = val;
diff --git a/target/riscv/translate.c b/target/riscv/translate.c
index 84dbfa6340..c7232de326 100644
--- a/target/riscv/translate.c
+++ b/target/riscv/translate.c
@@ -426,6 +426,10 @@ static void mark_fs_dirty(DisasContext *ctx)
 {
     TCGv tmp;
 
+    if (!has_ext(ctx, RVF)) {
+        return;
+    }
+
     if (ctx->mstatus_fs != MSTATUS_FS) {
         /* Remember the state change for the rest of the TB. */
         ctx->mstatus_fs = MSTATUS_FS;
-- 
2.17.1