[Qemu-devel] [PATCH 2/2] target-i386: kvm: enable all supported KVM features for -cpu host

[Eduardo Habkost <ehabkost@redhat.com>]

When using -cpu host, we don't need to use the kvm_default_features
variable, as the user is explicitly asking QEMU to enable all feature
supported by the host.

This changes the kvm_cpu_fill_host() code to use GET_SUPPORTED_CPUID to
initialize the kvm_features field, so we get all host KVM features
enabled.

This will also allow use to properly check/enforce KVM features inside
kvm_check_features_against_host() later. For example, we will be able to
make this:

  $ qemu-system-x86_64 -cpu ...,+kvm_pv_eoi,enforce

refuse to start if kvm_pv_eoi is not supported by the host (after we fix
kvm_check_features_against_host() to check KVM flags as well).

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
---
 target-i386/cpu.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/target-i386/cpu.c b/target-i386/cpu.c
index 6e2d32d..76f19f0 100644
--- a/target-i386/cpu.c
+++ b/target-i386/cpu.c
@@ -900,6 +900,8 @@ static void kvm_cpu_fill_host(x86_def_t *x86_cpu_def)
     /* Other KVM-specific feature fields: */
     x86_cpu_def->svm_features =
                 kvm_arch_get_supported_cpuid(s, 0x8000000A, 0, R_EDX);
+    x86_cpu_def->kvm_features =
+                kvm_arch_get_supported_cpuid(s, KVM_CPUID_FEATURES, 0, R_EAX);
 
 #endif /* CONFIG_KVM */
 }
-- 
1.7.11.7