KVM: Add helper to run KVM_CHECK_EXTENSION on vm fd

We now can call KVM_CHECK_EXTENSION on the kvm fd or on the vm fd, whereas
the vm version is more accurate when it comes to PPC KVM.

Add a helper to make the vm version available that falls back to the non-vm
variant if the vm one is not available yet to stay compatible.
Signed-off-by: NAlexander Graf <agraf@suse.de>

include/sysemu/kvm.h

@@ -303,6 +303,8 @@ bool kvm_arch_stop_on_emulation_error(CPUState *cpu);
 
 int kvm_check_extension(KVMState *s, unsigned int extension);
 
+int kvm_vm_check_extension(KVMState *s, unsigned int extension);
+
 #define kvm_vm_enable_cap(s, capability, cap_flags, ...)             \
     ({                                                               \
         struct kvm_enable_cap cap = {                                \

kvm-all.c

@@ -493,6 +493,19 @@ int kvm_check_extension(KVMState *s, unsigned int extension)
     return ret;
 }
 
+int kvm_vm_check_extension(KVMState *s, unsigned int extension)
+{
+    int ret;
+
+    ret = kvm_vm_ioctl(s, KVM_CHECK_EXTENSION, extension);
+    if (ret < 0) {
+        /* VM wide version not implemented, use global one instead */
+        ret = kvm_check_extension(s, extension);
+    }
+
+    return ret;
+}
+
 static int kvm_set_ioeventfd_mmio(int fd, hwaddr addr, uint32_t val,
                                   bool assign, uint32_t size, bool datamatch)
 {