KVM does not have the means to support enabling the rva22u64 profile.
The main reasons are:

- we're missing support for some mandatory rva22u64 extensions in the
  KVM module;

- we can't make promises about enabling a profile since it all depends
  on host support in the end.

We'll revisit this decision in the future if needed. For now mark the
'rva22u64' profile as unavailable when running a KVM CPU:

$ qemu-system-riscv64 -machine virt,accel=kvm -cpu rv64,rva22u64=true
qemu-system-riscv64: can't apply global rv64-riscv-cpu.rva22u64=true:
    'rva22u64' is not available with KVM

Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: LIU Zhiwei <zhiwei_liu@linux.alibaba.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
---
 target/riscv/kvm/kvm-cpu.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/target/riscv/kvm/kvm-cpu.c b/target/riscv/kvm/kvm-cpu.c
index 78fa1fa162..9c6ff774b5 100644
--- a/target/riscv/kvm/kvm-cpu.c
+++ b/target/riscv/kvm/kvm-cpu.c
@@ -398,7 +398,7 @@ static void cpu_set_cfg_unavailable(Object *obj, Visitor *v,
     }
 
     if (value) {
-        error_setg(errp, "extension %s is not available with KVM",
+        error_setg(errp, "'%s' is not available with KVM",
                    propname);
     }
 }
@@ -479,6 +479,11 @@ static void kvm_riscv_add_cpu_user_properties(Object *cpu_obj)
     riscv_cpu_add_kvm_unavail_prop_array(cpu_obj, riscv_cpu_extensions);
     riscv_cpu_add_kvm_unavail_prop_array(cpu_obj, riscv_cpu_vendor_exts);
     riscv_cpu_add_kvm_unavail_prop_array(cpu_obj, riscv_cpu_experimental_exts);
+
+   /* We don't have the needed KVM support for profiles */
+    for (i = 0; riscv_profiles[i] != NULL; i++) {
+        riscv_cpu_add_kvm_unavail_prop(cpu_obj, riscv_profiles[i]->name);
+    }
 }
 
 static int kvm_riscv_get_regs_core(CPUState *cs)
-- 
2.41.0