target/riscv: Use cpu_loop_exit_restore directly from mmu faults

The riscv_raise_exception function stores its argument into
exception_index and then exits to the main loop.  When we
have already set exception_index, we can just exit directly.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-Id: <20220401125948.79292-2-richard.henderson@linaro.org>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

target/riscv/cpu_helper.c

@@ -1150,7 +1150,7 @@ void riscv_cpu_do_transaction_failed(CPUState *cs, hwaddr physaddr,
     env->badaddr = addr;
     env->two_stage_lookup = riscv_cpu_virt_enabled(env) ||
                             riscv_cpu_two_stage_lookup(mmu_idx);
-    riscv_raise_exception(&cpu->env, cs->exception_index, retaddr);
+    cpu_loop_exit_restore(cs, retaddr);
 }
 
 void riscv_cpu_do_unaligned_access(CPUState *cs, vaddr addr,
@@ -1175,7 +1175,7 @@ void riscv_cpu_do_unaligned_access(CPUState *cs, vaddr addr,
     env->badaddr = addr;
     env->two_stage_lookup = riscv_cpu_virt_enabled(env) ||
                             riscv_cpu_two_stage_lookup(mmu_idx);
-    riscv_raise_exception(env, cs->exception_index, retaddr);
+    cpu_loop_exit_restore(cs, retaddr);
 }
 
 bool riscv_cpu_tlb_fill(CPUState *cs, vaddr address, int size,
@@ -1311,7 +1311,7 @@ bool riscv_cpu_tlb_fill(CPUState *cs, vaddr address, int size,
                             first_stage_error,
                             riscv_cpu_virt_enabled(env) ||
                                 riscv_cpu_two_stage_lookup(mmu_idx));
-        riscv_raise_exception(env, cs->exception_index, retaddr);
+        cpu_loop_exit_restore(cs, retaddr);
     }
 
     return true;