Re: [PATCH v2 2/6] target/riscv: hardwire mstatus.FS to zero when enable zfinx

[Weiwei Li]

Thanks for your comments.

在 2022/1/1 上午3:56, Richard Henderson 写道:
On 12/30/21 7:23 PM, Weiwei Li wrote:
@@ -363,6 +363,10 @@ static void riscv_cpu_reset(DeviceState *dev)
      env->misa_mxl = env->misa_mxl_max;
      env->priv = PRV_M;
      env->mstatus &= ~(MSTATUS_MIE | MSTATUS_MPRV);
+    /* hardwire mstatus.FS to zero when enable zfinx */
+    if (RISCV_CPU(env_cpu(env))->cfg.ext_zfinx) {
+        env->mstatus &= ~MSTATUS_FS;
+    }

This shouldn't be necessary because it should never have been set.
Yes, I think so. However, I have a question about MSTATUS_MIE and 
MSTATUS_MPRV, will they be set before cpu reset?

-    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;
+    /* hardwire mstatus.FS to zero when enable zfinx */
+    if (!RISCV_CPU(env_cpu(env))->cfg.ext_zfinx) {
+        mstatus_mask |= MSTATUS_FS;
+    }

I would think it would be more correct to have a positive test for 
RVF, rather than a negative test for ZFINX?
It may  deviate from the original value of mstatus_mask with a positive 
test for RVF.


r~