KVM: selftests: Print a more helpful message for EACCESS in access tracking test

Use open_path_or_exit() helper to probe /sys/kernel/mm/page_idle/bitmap in
the access tracking perf test so that a helpful/pertinent SKIP message is
printed if the file exists but is inaccessible, e.g. because the file has
the kernel's default 0600 permissions.

Cc: James Houghton <jthoughton@google.com>
Link: https://lore.kernel.org/r/20250516215909.2551628-5-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

diff --git a/tools/testing/selftests/kvm/access_tracking_perf_test.c b/tools/testing/selftests/kvm/access_tracking_perf_test.c
index da7196fd1b2307c99139b1bc317c6e4600419b83..c9de66537ec34f3fbfe274da0ef1ebbc96eb11e4 100644 (file)
--- a/tools/testing/selftests/kvm/access_tracking_perf_test.c
+++ b/tools/testing/selftests/kvm/access_tracking_perf_test.c
@@ -596,11 +596,8 @@ int main(int argc, char *argv[])
                if (ret)
                        return ret;
        } else {
-               page_idle_fd = open("/sys/kernel/mm/page_idle/bitmap", O_RDWR);
-               __TEST_REQUIRE(page_idle_fd >= 0,
-                              "Couldn't open /sys/kernel/mm/page_idle/bitmap. "
-                              "Is CONFIG_IDLE_PAGE_TRACKING enabled?");
-
+               page_idle_fd = __open_path_or_exit("/sys/kernel/mm/page_idle/bitmap", O_RDWR,
+                                                  "Is CONFIG_IDLE_PAGE_TRACKING enabled?");
                close(page_idle_fd);
 
                puts("Using page_idle for aging");