target/riscv: adding high part of some csrs

Adding the high part of a very minimal set of csr.

Signed-off-by: Frédéric Pétrot <frederic.petrot@univ-grenoble-alpes.fr>
Co-authored-by: Fabien Portas <fabien.portas@grenoble-inp.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-id: 20220106210108.138226-16-frederic.petrot@univ-grenoble-alpes.fr
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

target/riscv/cpu.h

@@ -195,6 +195,10 @@ struct CPURISCVState {
     target_ulong hgatp;
     uint64_t htimedelta;
 
+    /* Upper 64-bits of 128-bit CSRs */
+    uint64_t mscratchh;
+    uint64_t sscratchh;
+
     /* Virtual CSRs */
     /*
      * For RV32 this is 32-bit vsstatus and 32-bit vsstatush.

target/riscv/machine.c

@@ -179,6 +179,8 @@ static const VMStateDescription vmstate_rv128 = {
     .needed = rv128_needed,
     .fields = (VMStateField[]) {
         VMSTATE_UINTTL_ARRAY(env.gprh, RISCVCPU, 32),
+        VMSTATE_UINT64(env.mscratchh, RISCVCPU),
+        VMSTATE_UINT64(env.sscratchh, RISCVCPU),
         VMSTATE_END_OF_LIST()
     }
 };