[PATCH v7 12/16] target/riscv/tcg: handle profile MISA bits

[Daniel Henrique Barboza]

The profile support is handling multi-letter extensions only. Let's add
support for MISA bits as well.

We'll go through every known MISA bit. If the profile doesn't declare
the bit as mandatory, ignore it. Otherwise, set the bit in env->misa_ext
and env->misa_ext_mask.

Now that we're setting profile MISA bits, one can use the rv64i CPU to boot
Linux using the following options:

-cpu rv64i,rva22u64=true,s=true,zifencei=true

In the near future, when rva22s64 (where both 's' and 'zifencei' are
mandatory) support is added, rv64i will be able to boot Linux loading
rva22s64 and no additional flags.

Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Reviewed-by: LIU Zhiwei <zhiwei_liu@linux.alibaba.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
---
 target/riscv/tcg/tcg-cpu.c | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/target/riscv/tcg/tcg-cpu.c b/target/riscv/tcg/tcg-cpu.c
index b62890e568..4a915acff4 100644
--- a/target/riscv/tcg/tcg-cpu.c
+++ b/target/riscv/tcg/tcg-cpu.c
@@ -829,6 +829,27 @@ static void cpu_set_profile(Object *obj, Visitor *v, const 
char *name,
     profile->user_set = true;
     profile->enabled = value;
 
+    for (i = 0; misa_bits[i] != 0; i++) {
+        uint32_t bit = misa_bits[i];
+
+        if  (!(profile->misa_ext & bit)) {
+            continue;
+        }
+
+        if (bit == RVI && !profile->enabled) {
+            /*
+             * Disabling profiles will not disable the base
+             * ISA RV64I.
+             */
+            continue;
+        }
+
+        g_hash_table_insert(misa_ext_user_opts,
+                            GUINT_TO_POINTER(bit),
+                            (gpointer)value);
+        riscv_cpu_write_misa_bit(cpu, bit, profile->enabled);
+    }
+
     for (i = 0; profile->ext_offsets[i] != RISCV_PROFILE_EXT_LIST_END; i++) {
         ext_offset = profile->ext_offsets[i];
 
-- 
2.41.0