kvm tools: Add kvm__has_cap() to check whether a cap is available on the host

Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>

include/kvm/kvm.h

@@ -81,4 +81,6 @@ static inline void *guest_flat_to_host(struct kvm *kvm, unsigned long offset)
 	return kvm->ram_start + offset;
 }
 
+bool kvm__has_cap(struct kvm *kvm, u32 cap);
+
 #endif /* KVM__KVM_H */

kvm.c

@@ -520,3 +520,8 @@ void kvm__notify_paused(void)
 	mutex_lock(&pause_lock);
 	mutex_unlock(&pause_lock);
 }
+
+bool kvm__has_cap(struct kvm *kvm, u32 cap)
+{
+	return ioctl(kvm->sys_fd, KVM_CHECK_EXTENSION, cap) == 0;
+}