A bare bones 32 bit RVI CPU, rv32i, will make users lives easier when a
full customized 32 bit CPU is desired, and users won't need to disable
defaults by hand as they would with the rv32 CPU. [1] has an example of
a situation that would be avoided with rv32i.

In fact, add bare bones CPUs for RVE as well. Trying to use RVE in QEMU
requires one to disable every single default extension, including RVI,
and then add the desirable extension set. Adding rv32e/rv64e makes it
more pleasant to use embedded CPUs in QEMU.

[1] https://lore.kernel.org/qemu-riscv/258be47f-97be-4308-bed5-dc34ef7ff954@Spark/

Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
---
 target/riscv/cpu-qom.h |  3 +++
 target/riscv/cpu.c     | 21 +++++++++++++++++++++
 2 files changed, 24 insertions(+)

diff --git a/target/riscv/cpu-qom.h b/target/riscv/cpu-qom.h
index 9219c2fcc3..3670cfe6d9 100644
--- a/target/riscv/cpu-qom.h
+++ b/target/riscv/cpu-qom.h
@@ -34,7 +34,10 @@
 #define TYPE_RISCV_CPU_BASE32           RISCV_CPU_TYPE_NAME("rv32")
 #define TYPE_RISCV_CPU_BASE64           RISCV_CPU_TYPE_NAME("rv64")
 #define TYPE_RISCV_CPU_BASE128          RISCV_CPU_TYPE_NAME("x-rv128")
+#define TYPE_RISCV_CPU_RV32I            RISCV_CPU_TYPE_NAME("rv32i")
+#define TYPE_RISCV_CPU_RV32E            RISCV_CPU_TYPE_NAME("rv32e")
 #define TYPE_RISCV_CPU_RV64I            RISCV_CPU_TYPE_NAME("rv64i")
+#define TYPE_RISCV_CPU_RV64E            RISCV_CPU_TYPE_NAME("rv64e")
 #define TYPE_RISCV_CPU_RVA22U64         RISCV_CPU_TYPE_NAME("rva22u64")
 #define TYPE_RISCV_CPU_RVA22S64         RISCV_CPU_TYPE_NAME("rva22s64")
 #define TYPE_RISCV_CPU_IBEX             RISCV_CPU_TYPE_NAME("lowrisc-ibex")
diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c
index 9b6e03a655..687d647c0c 100644
--- a/target/riscv/cpu.c
+++ b/target/riscv/cpu.c
@@ -610,6 +610,12 @@ static void rv64i_bare_cpu_init(Object *obj)
     CPURISCVState *env = &RISCV_CPU(obj)->env;
     riscv_cpu_set_misa(env, MXL_RV64, RVI);
 }
+
+static void rv64e_bare_cpu_init(Object *obj)
+{
+    CPURISCVState *env = &RISCV_CPU(obj)->env;
+    riscv_cpu_set_misa(env, MXL_RV64, RVE);
+}
 #else
 static void rv32_base_cpu_init(Object *obj)
 {
@@ -696,6 +702,18 @@ static void rv32_imafcu_nommu_cpu_init(Object *obj)
     cpu->cfg.ext_zicsr = true;
     cpu->cfg.pmp = true;
 }
+
+static void rv32i_bare_cpu_init(Object *obj)
+{
+    CPURISCVState *env = &RISCV_CPU(obj)->env;
+    riscv_cpu_set_misa(env, MXL_RV32, RVI);
+}
+
+static void rv32e_bare_cpu_init(Object *obj)
+{
+    CPURISCVState *env = &RISCV_CPU(obj)->env;
+    riscv_cpu_set_misa(env, MXL_RV32, RVE);
+}
 #endif
 
 static ObjectClass *riscv_cpu_class_by_name(const char *cpu_model)
@@ -2428,6 +2446,8 @@ static const TypeInfo riscv_cpu_type_infos[] = {
     DEFINE_VENDOR_CPU(TYPE_RISCV_CPU_SIFIVE_E31,  rv32_sifive_e_cpu_init),
     DEFINE_VENDOR_CPU(TYPE_RISCV_CPU_SIFIVE_E34,  rv32_imafcu_nommu_cpu_init),
     DEFINE_VENDOR_CPU(TYPE_RISCV_CPU_SIFIVE_U34,  rv32_sifive_u_cpu_init),
+    DEFINE_BARE_CPU(TYPE_RISCV_CPU_RV32I, rv32i_bare_cpu_init),
+    DEFINE_BARE_CPU(TYPE_RISCV_CPU_RV32E, rv32e_bare_cpu_init),
 #elif defined(TARGET_RISCV64)
     DEFINE_DYNAMIC_CPU(TYPE_RISCV_CPU_BASE64,   rv64_base_cpu_init),
     DEFINE_VENDOR_CPU(TYPE_RISCV_CPU_SIFIVE_E51,  rv64_sifive_e_cpu_init),
@@ -2437,6 +2457,7 @@ static const TypeInfo riscv_cpu_type_infos[] = {
     DEFINE_VENDOR_CPU(TYPE_RISCV_CPU_VEYRON_V1,   rv64_veyron_v1_cpu_init),
     DEFINE_DYNAMIC_CPU(TYPE_RISCV_CPU_BASE128,  rv128_base_cpu_init),
     DEFINE_BARE_CPU(TYPE_RISCV_CPU_RV64I, rv64i_bare_cpu_init),
+    DEFINE_BARE_CPU(TYPE_RISCV_CPU_RV64E, rv64e_bare_cpu_init),
     DEFINE_PROFILE_CPU(TYPE_RISCV_CPU_RVA22U64, rva22u64_profile_cpu_init),
     DEFINE_PROFILE_CPU(TYPE_RISCV_CPU_RVA22S64, rva22s64_profile_cpu_init),
 #endif
-- 
2.43.0