KVM: selftests: Rework debug message printing

There were a few problems with the way we output "debug" messages.
The first is that we used DEBUG() which is defined when NDEBUG is
not defined, but NDEBUG will never be defined for kselftests
because it relies too much on assert(). The next is that most
of the DEBUG() messages were actually "info" messages, which
users may want to turn off if they just want a silent test that
either completes or asserts. Finally, a debug message output from
a library function, and thus for all tests, was annoying when its
information wasn't interesting for a test.

Rework these messages so debug messages only output when DEBUG
is defined and info messages output unless QUIET is defined.
Also name the functions pr_debug and pr_info and make sure that
when they're disabled we eat all the inputs. The later avoids
unused variable warnings when the variables were only defined
for the purpose of printing.

Signed-off-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

2 files changed, 13 insertions, 6 deletions

diff --git a/tools/testing/selftests/kvm/include/kvm_util.h b/tools/testing/selftests/kvm/include/kvm_util.h
index 1dc13bfa88b7..bc7c67913fe0 100644
--- a/tools/testing/selftests/kvm/include/kvm_util.h
+++ b/tools/testing/selftests/kvm/include/kvm_util.h
@@ -24,12 +24,6 @@ struct kvm_vm;
 typedef uint64_t vm_paddr_t; /* Virtual Machine (Guest) physical address */
 typedef uint64_t vm_vaddr_t; /* Virtual Machine (Guest) virtual address */
 
-#ifndef NDEBUG
-#define DEBUG(...) printf(__VA_ARGS__);
-#else
-#define DEBUG(...)
-#endif
-
 /* Minimum allocated guest virtual and physical addresses */
 #define KVM_UTIL_MIN_VADDR		0x2000
 
diff --git a/tools/testing/selftests/kvm/include/test_util.h b/tools/testing/selftests/kvm/include/test_util.h
index 920328ca5f7e..c921ea719ae0 100644
--- a/tools/testing/selftests/kvm/include/test_util.h
+++ b/tools/testing/selftests/kvm/include/test_util.h
@@ -19,6 +19,19 @@
 #include <fcntl.h>
 #include "kselftest.h"
 
+static inline int _no_printf(const char *format, ...) { return 0; }
+
+#ifdef DEBUG
+#define pr_debug(...) printf(__VA_ARGS__)
+#else
+#define pr_debug(...) _no_printf(__VA_ARGS__)
+#endif
+#ifndef QUIET
+#define pr_info(...) printf(__VA_ARGS__)
+#else
+#define pr_info(...) _no_printf(__VA_ARGS__)
+#endif
+
 ssize_t test_write(int fd, const void *buf, size_t count);
 ssize_t test_read(int fd, void *buf, size_t count);
 int test_seq_read(const char *path, char **bufp, size_t *sizep);