KVM: selftests: Return an 'unsigned int' from kvm_check_cap()

Return an 'unsigned int' instead of a signed 'int' from kvm_check_cap(),
to make it more obvious that kvm_check_cap() can never return a negative
value due to its assertion that the return is ">= 0".
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

tools/testing/selftests/kvm/include/kvm_util_base.h

@@ -167,7 +167,7 @@ extern const struct vm_guest_mode_params vm_guest_mode_params[];
 
 int open_path_or_exit(const char *path, int flags);
 int open_kvm_dev_path_or_exit(void);
-int kvm_check_cap(long cap);
+unsigned int kvm_check_cap(long cap);
 
 #define __KVM_SYSCALL_ERROR(_name, _ret) \
 	"%s failed, rc: %i errno: %i (%s)", (_name), (_ret), errno, strerror(errno)

tools/testing/selftests/kvm/kvm_binary_stats_test.c

@@ -213,7 +213,7 @@ int main(int argc, char *argv[])
 	}
 
 	/* Check the extension for binary stats */
-	if (kvm_check_cap(KVM_CAP_BINARY_STATS_FD) <= 0) {
+	if (!kvm_check_cap(KVM_CAP_BINARY_STATS_FD)) {
 		print_skip("Binary form statistics interface is not supported");
 		exit(KSFT_SKIP);
 	}

tools/testing/selftests/kvm/lib/kvm_util.c

@@ -69,7 +69,7 @@ int open_kvm_dev_path_or_exit(void)
  * Looks up and returns the value corresponding to the capability
  * (KVM_CAP_*) given by cap.
  */
-int kvm_check_cap(long cap)
+unsigned int kvm_check_cap(long cap)
 {
 	int ret;
 	int kvm_fd;