target/riscv: Allow users to force enable AIA CSRs in HART

We add "x-aia" command-line option for RISC-V HART using which
allows users to force enable CPU AIA CSRs without changing the
interrupt controller available in RISC-V machine.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Signed-off-by: Anup Patel <anup@brainfault.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Frank Chang <frank.chang@sifive.com>
Message-id: 20220204174700.534953-18-anup@brainfault.org
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

target/riscv/cpu.c

@@ -537,6 +537,10 @@ static void riscv_cpu_realize(DeviceState *dev, Error **errp)
         }
     }
 
+    if (cpu->cfg.aia) {
+        riscv_set_feature(env, RISCV_FEATURE_AIA);
+    }
+
     set_resetvec(env, cpu->cfg.resetvec);
 
     /* Validate that MISA_MXL is set properly. */
@@ -782,6 +786,7 @@ static Property riscv_cpu_properties[] = {
     DEFINE_PROP_BOOL("x-j", RISCVCPU, cfg.ext_j, false),
     /* ePMP 0.9.3 */
     DEFINE_PROP_BOOL("x-epmp", RISCVCPU, cfg.epmp, false),
+    DEFINE_PROP_BOOL("x-aia", RISCVCPU, cfg.aia, false),
 
     DEFINE_PROP_UINT64("resetvec", RISCVCPU, cfg.resetvec, DEFAULT_RSTVEC),
     DEFINE_PROP_END_OF_LIST(),

target/riscv/cpu.h

@@ -376,6 +376,7 @@ struct RISCVCPUConfig {
     bool mmu;
     bool pmp;
     bool epmp;
+    bool aia;
     uint64_t resetvec;
 };