The 'host' CPU model isn't supported until KVM or HVF is enabled.
For example, the following error messages are seen when the guest
is started with option '-cpu cortex-a8'.

  qemu-system-aarch64: Invalid CPU type: cortex-a8-arm-cpu
  The valid models are: cortex-a7, cortex-a15, cortex-a35,
  cortex-a55, cortex-a72, cortex-a76, a64fx, neoverse-n1,
  neoverse-v1, cortex-a53, cortex-a57, host, max

Hide 'host' CPU model until KVM or HVF is enabled.

Signed-off-by: Gavin Shan <gshan@redhat.com>
---
 hw/arm/virt.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/hw/arm/virt.c b/hw/arm/virt.c
index debd85614e..2562ca0c1e 100644
--- a/hw/arm/virt.c
+++ b/hw/arm/virt.c
@@ -217,7 +217,9 @@ static const char * const valid_cpu_types[] = {
 #endif
     ARM_CPU_TYPE_NAME("cortex-a53"),
     ARM_CPU_TYPE_NAME("cortex-a57"),
+#if defined(CONFIG_KVM) || defined(CONFIG_HVF)
     ARM_CPU_TYPE_NAME("host"),
+#endif
     ARM_CPU_TYPE_NAME("max"),
     NULL
 };
@@ -236,7 +238,9 @@ static const char * const valid_cpu_models[] = {
 #endif
     "cortex-a53",
     "cortex-a57",
+#if defined(CONFIG_KVM) || defined(CONFIG_HVF)
     "host",
+#endif
     "max",
     NULL
 };
-- 
2.41.0