target/riscv: add 'rva22u64' CPU

This CPU was suggested by Alistair [1] and others during the profile
design discussions. It consists of the bare 'rv64i' CPU with rva22u64
enabled by default, like an alias of '-cpu rv64i,rva22u64=true'.

Users now have an even easier way of consuming this user-mode profile by
doing '-cpu rva22u64'. Extensions can be enabled/disabled at will on top
of it.

We can boot Linux with this "user-mode" CPU by doing:

-cpu rva22u64,sv39=true,s=true,zifencei=true

[1] https://lore.kernel.org/qemu-riscv/CAKmqyKP7xzZ9Sx=-Lbx2Ob0qCfB7Z+JO944FQ2TQ+49mqo0q_Q@mail.gmail.com/

Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-ID: <20231218125334.37184-19-dbarboza@ventanamicro.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

target/riscv/cpu-qom.h

@@ -35,6 +35,7 @@
 #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_RV64I            RISCV_CPU_TYPE_NAME("rv64i")
+#define TYPE_RISCV_CPU_RVA22U64         RISCV_CPU_TYPE_NAME("rva22u64")
 #define TYPE_RISCV_CPU_IBEX             RISCV_CPU_TYPE_NAME("lowrisc-ibex")
 #define TYPE_RISCV_CPU_SHAKTI_C         RISCV_CPU_TYPE_NAME("shakti-c")
 #define TYPE_RISCV_CPU_SIFIVE_E31       RISCV_CPU_TYPE_NAME("sifive-e31")

target/riscv/cpu.c

@@ -1575,6 +1575,15 @@ static Property riscv_cpu_properties[] = {
     DEFINE_PROP_END_OF_LIST(),
 };
 
+#if defined(TARGET_RISCV64)
+static void rva22u64_profile_cpu_init(Object *obj)
+{
+    rv64i_bare_cpu_init(obj);
+
+    RVA22U64.enabled = true;
+}
+#endif
+
 static const gchar *riscv_gdb_arch_name(CPUState *cs)
 {
     RISCVCPU *cpu = RISCV_CPU(cs);
@@ -1836,6 +1845,13 @@ char *riscv_isa_string(RISCVCPU *cpu)
         .instance_init = initfn            \
     }
 
+#define DEFINE_PROFILE_CPU(type_name, initfn) \
+    {                                         \
+        .name = type_name,                    \
+        .parent = TYPE_RISCV_BARE_CPU,        \
+        .instance_init = initfn               \
+    }
+
 static const TypeInfo riscv_cpu_type_infos[] = {
     {
         .name = TYPE_RISCV_CPU,
@@ -1880,6 +1896,7 @@ 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_PROFILE_CPU(TYPE_RISCV_CPU_RVA22U64, rva22u64_profile_cpu_init),
 #endif
 };
 

target/riscv/tcg/tcg-cpu.c

@@ -1100,6 +1100,15 @@ static void riscv_cpu_add_profiles(Object *cpu_obj)
         object_property_add(cpu_obj, profile->name, "bool",
                             cpu_get_profile, cpu_set_profile,
                             NULL, (void *)profile);
+
+        /*
+         * CPUs might enable a profile right from the start.
+         * Enable its mandatory extensions right away in this
+         * case.
+         */
+        if (profile->enabled) {
+            object_property_set_bool(cpu_obj, profile->name, true, NULL);
+        }
     }
 }