target/riscv: configure and turn on vector extension from command line

Vector extension is default off. The only way to use vector extension is
1. use cpu rv32 or rv64
2. turn on it by command line
   "-cpu rv64,x-v=true,vlen=128,elen=64,vext_spec=v0.7.1".

vlen is the vector register length, default value is 128 bit.
elen is the max operator size in bits, default value is 64 bit.
vext_spec is the vector specification version, default value is v0.7.1.
These properties can be specified with other values.

Signed-off-by: LIU Zhiwei <[email protected]>
Reviewed-by: Alistair Francis <[email protected]>
Reviewed-by: Richard Henderson <[email protected]>
Message-Id: <[email protected]>
Signed-off-by: Alistair Francis <[email protected]>

Author: LIU Zhiwei

target/riscv/cpu.c

@@ -430,6 +430,45 @@ static void riscv_cpu_realize(DeviceState *dev, Error **errp)
         if (cpu->cfg.ext_h) {
             target_misa |= RVH;
         }
+        if (cpu->cfg.ext_v) {
+            target_misa |= RVV;
+            if (!is_power_of_2(cpu->cfg.vlen)) {
+                error_setg(errp,
+                        "Vector extension VLEN must be power of 2");
+                return;
+            }
+            if (cpu->cfg.vlen > RV_VLEN_MAX || cpu->cfg.vlen < 128) {
+                error_setg(errp,
+                        "Vector extension implementation only supports VLEN "
+                        "in the range [128, %d]", RV_VLEN_MAX);
+                return;
+            }
+            if (!is_power_of_2(cpu->cfg.elen)) {
+                error_setg(errp,
+                        "Vector extension ELEN must be power of 2");
+                return;
+            }
+            if (cpu->cfg.elen > 64 || cpu->cfg.vlen < 8) {
+                error_setg(errp,
+                        "Vector extension implementation only supports ELEN "
+                        "in the range [8, 64]");
+                return;
+            }
+            if (cpu->cfg.vext_spec) {
+                if (!g_strcmp0(cpu->cfg.vext_spec, "v0.7.1")) {
+                    vext_version = VEXT_VERSION_0_07_1;
+                } else {
+                    error_setg(errp,
+                           "Unsupported vector spec version '%s'",
+                           cpu->cfg.vext_spec);
+                    return;
+                }
+            } else {
+                qemu_log("vector verison is not specified, "
+                        "use the default value v0.7.1\n");
+            }
+            set_vext_version(env, vext_version);
+        }
 
         set_misa(env, RVXLEN | target_misa);
     }
@@ -469,10 +508,14 @@ static Property riscv_cpu_properties[] = {
     DEFINE_PROP_BOOL("u", RISCVCPU, cfg.ext_u, true),
     /* This is experimental so mark with 'x-' */
     DEFINE_PROP_BOOL("x-h", RISCVCPU, cfg.ext_h, false),
+    DEFINE_PROP_BOOL("x-v", RISCVCPU, cfg.ext_v, false),
     DEFINE_PROP_BOOL("Counters", RISCVCPU, cfg.ext_counters, true),
     DEFINE_PROP_BOOL("Zifencei", RISCVCPU, cfg.ext_ifencei, true),
     DEFINE_PROP_BOOL("Zicsr", RISCVCPU, cfg.ext_icsr, true),
     DEFINE_PROP_STRING("priv_spec", RISCVCPU, cfg.priv_spec),
+    DEFINE_PROP_STRING("vext_spec", RISCVCPU, cfg.vext_spec),
+    DEFINE_PROP_UINT16("vlen", RISCVCPU, cfg.vlen, 128),
+    DEFINE_PROP_UINT16("elen", RISCVCPU, cfg.elen, 64),
     DEFINE_PROP_BOOL("mmu", RISCVCPU, cfg.mmu, true),
     DEFINE_PROP_BOOL("pmp", RISCVCPU, cfg.pmp, true),
     DEFINE_PROP_END_OF_LIST(),

target/riscv/cpu.h

@@ -92,7 +92,7 @@ typedef struct CPURISCVState CPURISCVState;
 
 #include "pmp.h"
 
-#define RV_VLEN_MAX 512
+#define RV_VLEN_MAX 256
 
 FIELD(VTYPE, VLMUL, 0, 2)
 FIELD(VTYPE, VSEW, 2, 3)
@@ -279,12 +279,14 @@ typedef struct RISCVCPU {
         bool ext_s;
         bool ext_u;
         bool ext_h;
+        bool ext_v;
         bool ext_counters;
         bool ext_ifencei;
         bool ext_icsr;
 
         char *priv_spec;
         char *user_spec;
+        char *vext_spec;
         uint16_t vlen;
         uint16_t elen;
         bool mmu;