selftests/mm: smoke test UFFD_FEATURE_WP_UNPOPULATED

Enable it by default on the stress test, and add some smoke tests for the
pte markers on anonymous.

Link: https://lkml.kernel.org/r/20230309223711.823547-3-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Muhammad Usama Anjum <usama.anjum@collabora.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Paul Gofman <pgofman@codeweavers.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/tools/testing/selftests/mm/userfaultfd.c b/tools/testing/selftests/mm/userfaultfd.c
index 7f22844ed7040e6b9bfcea2982f715bfb9c5e3ba..e030d63c031a9103fa02424cf87ce4668a72036e 100644 (file)
--- a/tools/testing/selftests/mm/userfaultfd.c
+++ b/tools/testing/selftests/mm/userfaultfd.c
@@ -1444,6 +1444,43 @@ static int pagemap_test_fork(bool present)
        return result;
 }
 
+static void userfaultfd_wp_unpopulated_test(int pagemap_fd)
+{
+       uint64_t value;
+
+       /* Test applying pte marker to anon unpopulated */
+       wp_range(uffd, (uint64_t)area_dst, page_size, true);
+       value = pagemap_read_vaddr(pagemap_fd, area_dst);
+       pagemap_check_wp(value, true);
+
+       /* Test unprotect on anon pte marker */
+       wp_range(uffd, (uint64_t)area_dst, page_size, false);
+       value = pagemap_read_vaddr(pagemap_fd, area_dst);
+       pagemap_check_wp(value, false);
+
+       /* Test zap on anon marker */
+       wp_range(uffd, (uint64_t)area_dst, page_size, true);
+       if (madvise(area_dst, page_size, MADV_DONTNEED))
+               err("madvise(MADV_DONTNEED) failed");
+       value = pagemap_read_vaddr(pagemap_fd, area_dst);
+       pagemap_check_wp(value, false);
+
+       /* Test fault in after marker removed */
+       *area_dst = 1;
+       value = pagemap_read_vaddr(pagemap_fd, area_dst);
+       pagemap_check_wp(value, false);
+       /* Drop it to make pte none again */
+       if (madvise(area_dst, page_size, MADV_DONTNEED))
+               err("madvise(MADV_DONTNEED) failed");
+
+       /* Test read-zero-page upon pte marker */
+       wp_range(uffd, (uint64_t)area_dst, page_size, true);
+       *(volatile char *)area_dst;
+       /* Drop it to make pte none again */
+       if (madvise(area_dst, page_size, MADV_DONTNEED))
+               err("madvise(MADV_DONTNEED) failed");
+}
+
 static void userfaultfd_pagemap_test(unsigned int test_pgsize)
 {
        struct uffdio_register uffdio_register;
@@ -1462,7 +1499,7 @@ static void userfaultfd_pagemap_test(unsigned int test_pgsize)
        /* Flush so it doesn't flush twice in parent/child later */
        fflush(stdout);
 
-       uffd_test_ctx_init(0);
+       uffd_test_ctx_init(UFFD_FEATURE_WP_UNPOPULATED);
 
        if (test_pgsize > page_size) {
                /* This is a thp test */
@@ -1482,6 +1519,10 @@ static void userfaultfd_pagemap_test(unsigned int test_pgsize)
 
        pagemap_fd = pagemap_open();
 
+       /* Smoke test WP_UNPOPULATED first when it's still empty */
+       if (test_pgsize == page_size)
+               userfaultfd_wp_unpopulated_test(pagemap_fd);
+
        /* Touch the page */
        *area_dst = 1;
        wp_range(uffd, (uint64_t)area_dst, test_pgsize, true);
@@ -1526,7 +1567,7 @@ static int userfaultfd_stress(void)
        struct uffdio_register uffdio_register;
        struct uffd_stats uffd_stats[nr_cpus];
 
-       uffd_test_ctx_init(0);
+       uffd_test_ctx_init(UFFD_FEATURE_WP_UNPOPULATED);
 
        if (posix_memalign(&area, page_size, page_size))
                err("out of memory");