From: LIU Zhiwei <zhiwei_liu@c-sky.com>

Signed-off-by: LIU Zhiwei <zhiwei_liu@c-sky.com>
Signed-off-by: Frank Chang <frank.chang@sifive.com>
---
 target/riscv/cpu_bits.h |  7 +++++++
 target/riscv/csr.c      | 21 +++++++++++++++++++++
 2 files changed, 28 insertions(+)

diff --git a/target/riscv/cpu_bits.h b/target/riscv/cpu_bits.h
index 5b0be0bb88..7afdd4814b 100644
--- a/target/riscv/cpu_bits.h
+++ b/target/riscv/cpu_bits.h
@@ -60,9 +60,16 @@
 #define CSR_VSTART          0x008
 #define CSR_VXSAT           0x009
 #define CSR_VXRM            0x00a
+#define CSR_VCSR            0x00f
 #define CSR_VL              0xc20
 #define CSR_VTYPE           0xc21
 
+/* VCSR fields */
+#define VCSR_VXSAT_SHIFT    0
+#define VCSR_VXSAT          (0x1 << VCSR_VXSAT_SHIFT)
+#define VCSR_VXRM_SHIFT     1
+#define VCSR_VXRM           (0x3 << VCSR_VXRM_SHIFT)
+
 /* User Timers and Counters */
 #define CSR_CYCLE           0xc00
 #define CSR_TIME            0xc01
diff --git a/target/riscv/csr.c b/target/riscv/csr.c
index 33c77be06e..e05acb5a24 100644
--- a/target/riscv/csr.c
+++ b/target/riscv/csr.c
@@ -252,6 +252,26 @@ static int write_vstart(CPURISCVState *env, int csrno, target_ulong val)
     return 0;
 }
 
+static int read_vcsr(CPURISCVState *env, int csrno, target_ulong *val)
+{
+    *val = (env->vxrm << VCSR_VXRM_SHIFT) | (env->vxsat << VCSR_VXSAT_SHIFT);
+    return 0;
+}
+
+static int write_vcsr(CPURISCVState *env, int csrno, target_ulong val)
+{
+#if !defined(CONFIG_USER_ONLY)
+    if (!env->debugger && !riscv_cpu_vector_enabled(env)) {
+        return -1;
+    }
+    env->mstatus |= MSTATUS_VS;
+#endif
+
+    env->vxrm = (val & VCSR_VXRM) >> VCSR_VXRM_SHIFT;
+    env->vxsat = (val & VCSR_VXSAT) >> VCSR_VXSAT_SHIFT;
+    return 0;
+}
+
 /* User Timers and Counters */
 static int read_instret(CPURISCVState *env, int csrno, target_ulong *val)
 {
@@ -1270,6 +1290,7 @@ static riscv_csr_operations csr_ops[CSR_TABLE_SIZE] = {
     [CSR_VSTART] =              { vs,   read_vstart,      write_vstart      },
     [CSR_VXSAT] =               { vs,   read_vxsat,       write_vxsat       },
     [CSR_VXRM] =                { vs,   read_vxrm,        write_vxrm        },
+    [CSR_VCSR] =                { vs,   read_vcsr,        write_vcsr        },
     [CSR_VL] =                  { vs,   read_vl                             },
     [CSR_VTYPE] =               { vs,   read_vtype                          },
     /* User Timers and Counters */
-- 
2.17.1

On 7/22/20 2:15 AM, frank.chang@sifive.com wrote:
> From: LIU Zhiwei <zhiwei_liu@c-sky.com>
> 
> Signed-off-by: LIU Zhiwei <zhiwei_liu@c-sky.com>
> Signed-off-by: Frank Chang <frank.chang@sifive.com>
> ---
>  target/riscv/cpu_bits.h |  7 +++++++
>  target/riscv/csr.c      | 21 +++++++++++++++++++++
>  2 files changed, 28 insertions(+)

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>


r~