target/riscv: update multi-letter extension KVM properties

We're now ready to update the multi-letter extensions status for KVM.

kvm_riscv_update_cpu_cfg_isa_ext() is called called during vcpu creation
time to verify which user options changes host defaults (via the 'user_set'
flag) and tries to write them back to KVM.

Failure to commit a change to KVM is only ignored in case KVM doesn't
know about the extension (-EINVAL error code) and the user wanted to
disable the given extension. Otherwise we're going to abort the boot
process.

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: <20230706101738.460804-19-dbarboza@ventanamicro.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

target/riscv/kvm.c

@@ -273,6 +273,32 @@ static void kvm_cpu_set_multi_ext_cfg(Object *obj, Visitor *v,
     kvm_cpu_cfg_set(cpu, multi_ext_cfg, value);
 }
 
+static void kvm_riscv_update_cpu_cfg_isa_ext(RISCVCPU *cpu, CPUState *cs)
+{
+    CPURISCVState *env = &cpu->env;
+    uint64_t id, reg;
+    int i, ret;
+
+    for (i = 0; i < ARRAY_SIZE(kvm_multi_ext_cfgs); i++) {
+        KVMCPUConfig *multi_ext_cfg = &kvm_multi_ext_cfgs[i];
+
+        if (!multi_ext_cfg->user_set) {
+            continue;
+        }
+
+        id = kvm_riscv_reg_id(env, KVM_REG_RISCV_ISA_EXT,
+                              multi_ext_cfg->kvm_reg_id);
+        reg = kvm_cpu_cfg_get(cpu, multi_ext_cfg);
+        ret = kvm_set_one_reg(cs, id, &reg);
+        if (ret != 0) {
+            error_report("Unable to %s extension %s in KVM, error %d",
+                         reg ? "enable" : "disable",
+                         multi_ext_cfg->name, ret);
+            exit(EXIT_FAILURE);
+        }
+    }
+}
+
 static void kvm_riscv_add_cpu_user_properties(Object *cpu_obj)
 {
     int i;
@@ -792,6 +818,7 @@ int kvm_arch_init_vcpu(CPUState *cs)
     }
 
     kvm_riscv_update_cpu_misa_ext(cpu, cs);
+    kvm_riscv_update_cpu_cfg_isa_ext(cpu, cs);
 
     return ret;
 }