From: Peter Xu <peterx@redhat.com>
To: linux-mm@kvack.org, linux-kernel@vger.kernel.org
Cc: David Hildenbrand <david@redhat.com>,
Hugh Dickins <hughd@google.com>, Maya Gokhale <gokhale2@llnl.gov>,
Jerome Glisse <jglisse@redhat.com>,
Pavel Emelyanov <xemul@virtuozzo.com>,
Johannes Weiner <hannes@cmpxchg.org>,
peterx@redhat.com, Martin Cracauer <cracauer@cons.org>,
Shaohua Li <shli@fb.com>,
Denis Plotnikov <dplotnikov@virtuozzo.com>,
Andrea Arcangeli <aarcange@redhat.com>,
Mike Kravetz <mike.kravetz@oracle.com>,
Marty McFadden <mcfadden8@llnl.gov>,
Mike Rapoport <rppt@linux.vnet.ibm.com>,
Mel Gorman <mgorman@suse.de>,
"Kirill A . Shutemov" <kirill@shutemov.name>,
"Dr . David Alan Gilbert" <dgilbert@redhat.com>
Subject: [PATCH v4 27/27] userfaultfd: selftests: add write-protect test
Date: Fri, 26 Apr 2019 12:51:51 +0800 [thread overview]
Message-ID: <20190426045151.19556-28-peterx@redhat.com> (raw)
In-Reply-To: <20190426045151.19556-1-peterx@redhat.com>
This patch adds uffd tests for write protection.
Instead of introducing new tests for it, let's simply squashing uffd-wp
tests into existing uffd-missing test cases. Changes are:
(1) Bouncing tests
We do the write-protection in two ways during the bouncing test:
- By using UFFDIO_COPY_MODE_WP when resolving MISSING pages: then
we'll make sure for each bounce process every single page will be
at least fault twice: once for MISSING, once for WP.
- By direct call UFFDIO_WRITEPROTECT on existing faulted memories:
To further torture the explicit page protection procedures of
uffd-wp, we split each bounce procedure into two halves (in the
background thread): the first half will be MISSING+WP for each
page as explained above. After the first half, we write protect
the faulted region in the background thread to make sure at least
half of the pages will be write protected again which is the first
half to test the new UFFDIO_WRITEPROTECT call. Then we continue
with the 2nd half, which will contain both MISSING and WP faulting
tests for the 2nd half and WP-only faults from the 1st half.
(2) Event/Signal test
Mostly previous tests but will do MISSING+WP for each page. For
sigbus-mode test we'll need to provide standalone path to handle the
write protection faults.
For all tests, do statistics as well for uffd-wp pages.
Signed-off-by: Peter Xu <peterx@redhat.com>
---
tools/testing/selftests/vm/userfaultfd.c | 157 +++++++++++++++++++----
1 file changed, 133 insertions(+), 24 deletions(-)
diff --git a/tools/testing/selftests/vm/userfaultfd.c b/tools/testing/selftests/vm/userfaultfd.c
index e5d12c209e09..bf1e10db72f5 100644
--- a/tools/testing/selftests/vm/userfaultfd.c
+++ b/tools/testing/selftests/vm/userfaultfd.c
@@ -56,6 +56,7 @@
#include <linux/userfaultfd.h>
#include <setjmp.h>
#include <stdbool.h>
+#include <assert.h>
#include "../kselftest.h"
@@ -78,6 +79,8 @@ static int test_type;
#define ALARM_INTERVAL_SECS 10
static volatile bool test_uffdio_copy_eexist = true;
static volatile bool test_uffdio_zeropage_eexist = true;
+/* Whether to test uffd write-protection */
+static bool test_uffdio_wp = false;
static bool map_shared;
static int huge_fd;
@@ -92,6 +95,7 @@ pthread_attr_t attr;
struct uffd_stats {
int cpu;
unsigned long missing_faults;
+ unsigned long wp_faults;
};
/* pthread_mutex_t starts at page offset 0 */
@@ -141,9 +145,29 @@ static void uffd_stats_reset(struct uffd_stats *uffd_stats,
for (i = 0; i < n_cpus; i++) {
uffd_stats[i].cpu = i;
uffd_stats[i].missing_faults = 0;
+ uffd_stats[i].wp_faults = 0;
}
}
+static void uffd_stats_report(struct uffd_stats *stats, int n_cpus)
+{
+ int i;
+ unsigned long long miss_total = 0, wp_total = 0;
+
+ for (i = 0; i < n_cpus; i++) {
+ miss_total += stats[i].missing_faults;
+ wp_total += stats[i].wp_faults;
+ }
+
+ printf("userfaults: %llu missing (", miss_total);
+ for (i = 0; i < n_cpus; i++)
+ printf("%lu+", stats[i].missing_faults);
+ printf("\b), %llu wp (", wp_total);
+ for (i = 0; i < n_cpus; i++)
+ printf("%lu+", stats[i].wp_faults);
+ printf("\b)\n");
+}
+
static int anon_release_pages(char *rel_area)
{
int ret = 0;
@@ -264,10 +288,15 @@ struct uffd_test_ops {
void (*alias_mapping)(__u64 *start, size_t len, unsigned long offset);
};
-#define ANON_EXPECTED_IOCTLS ((1 << _UFFDIO_WAKE) | \
+#define SHMEM_EXPECTED_IOCTLS ((1 << _UFFDIO_WAKE) | \
(1 << _UFFDIO_COPY) | \
(1 << _UFFDIO_ZEROPAGE))
+#define ANON_EXPECTED_IOCTLS ((1 << _UFFDIO_WAKE) | \
+ (1 << _UFFDIO_COPY) | \
+ (1 << _UFFDIO_ZEROPAGE) | \
+ (1 << _UFFDIO_WRITEPROTECT))
+
static struct uffd_test_ops anon_uffd_test_ops = {
.expected_ioctls = ANON_EXPECTED_IOCTLS,
.allocate_area = anon_allocate_area,
@@ -276,7 +305,7 @@ static struct uffd_test_ops anon_uffd_test_ops = {
};
static struct uffd_test_ops shmem_uffd_test_ops = {
- .expected_ioctls = ANON_EXPECTED_IOCTLS,
+ .expected_ioctls = SHMEM_EXPECTED_IOCTLS,
.allocate_area = shmem_allocate_area,
.release_pages = shmem_release_pages,
.alias_mapping = noop_alias_mapping,
@@ -300,6 +329,21 @@ static int my_bcmp(char *str1, char *str2, size_t n)
return 0;
}
+static void wp_range(int ufd, __u64 start, __u64 len, bool wp)
+{
+ struct uffdio_writeprotect prms = { 0 };
+
+ /* Write protection page faults */
+ prms.range.start = start;
+ prms.range.len = len;
+ /* Undo write-protect, do wakeup after that */
+ prms.mode = wp ? UFFDIO_WRITEPROTECT_MODE_WP : 0;
+
+ if (ioctl(ufd, UFFDIO_WRITEPROTECT, &prms))
+ fprintf(stderr, "clear WP failed for address 0x%Lx\n",
+ start), exit(1);
+}
+
static void *locking_thread(void *arg)
{
unsigned long cpu = (unsigned long) arg;
@@ -438,7 +482,10 @@ static int __copy_page(int ufd, unsigned long offset, bool retry)
uffdio_copy.dst = (unsigned long) area_dst + offset;
uffdio_copy.src = (unsigned long) area_src + offset;
uffdio_copy.len = page_size;
- uffdio_copy.mode = 0;
+ if (test_uffdio_wp)
+ uffdio_copy.mode = UFFDIO_COPY_MODE_WP;
+ else
+ uffdio_copy.mode = 0;
uffdio_copy.copy = 0;
if (ioctl(ufd, UFFDIO_COPY, &uffdio_copy)) {
/* real retval in ufdio_copy.copy */
@@ -495,15 +542,21 @@ static void uffd_handle_page_fault(struct uffd_msg *msg,
fprintf(stderr, "unexpected msg event %u\n",
msg->event), exit(1);
- if (bounces & BOUNCE_VERIFY &&
- msg->arg.pagefault.flags & UFFD_PAGEFAULT_FLAG_WRITE)
- fprintf(stderr, "unexpected write fault\n"), exit(1);
+ if (msg->arg.pagefault.flags & UFFD_PAGEFAULT_FLAG_WP) {
+ wp_range(uffd, msg->arg.pagefault.address, page_size, false);
+ stats->wp_faults++;
+ } else {
+ /* Missing page faults */
+ if (bounces & BOUNCE_VERIFY &&
+ msg->arg.pagefault.flags & UFFD_PAGEFAULT_FLAG_WRITE)
+ fprintf(stderr, "unexpected write fault\n"), exit(1);
- offset = (char *)(unsigned long)msg->arg.pagefault.address - area_dst;
- offset &= ~(page_size-1);
+ offset = (char *)(unsigned long)msg->arg.pagefault.address - area_dst;
+ offset &= ~(page_size-1);
- if (copy_page(uffd, offset))
- stats->missing_faults++;
+ if (copy_page(uffd, offset))
+ stats->missing_faults++;
+ }
}
static void *uffd_poll_thread(void *arg)
@@ -589,11 +642,30 @@ static void *uffd_read_thread(void *arg)
static void *background_thread(void *arg)
{
unsigned long cpu = (unsigned long) arg;
- unsigned long page_nr;
+ unsigned long page_nr, start_nr, mid_nr, end_nr;
+
+ start_nr = cpu * nr_pages_per_cpu;
+ end_nr = (cpu+1) * nr_pages_per_cpu;
+ mid_nr = (start_nr + end_nr) / 2;
+
+ /* Copy the first half of the pages */
+ for (page_nr = start_nr; page_nr < mid_nr; page_nr++)
+ copy_page_retry(uffd, page_nr * page_size);
- for (page_nr = cpu * nr_pages_per_cpu;
- page_nr < (cpu+1) * nr_pages_per_cpu;
- page_nr++)
+ /*
+ * If we need to test uffd-wp, set it up now. Then we'll have
+ * at least the first half of the pages mapped already which
+ * can be write-protected for testing
+ */
+ if (test_uffdio_wp)
+ wp_range(uffd, (unsigned long)area_dst + start_nr * page_size,
+ nr_pages_per_cpu * page_size, true);
+
+ /*
+ * Continue the 2nd half of the page copying, handling write
+ * protection faults if any
+ */
+ for (page_nr = mid_nr; page_nr < end_nr; page_nr++)
copy_page_retry(uffd, page_nr * page_size);
return NULL;
@@ -755,17 +827,31 @@ static int faulting_process(int signal_test)
}
for (nr = 0; nr < split_nr_pages; nr++) {
+ int steps = 1;
+ unsigned long offset = nr * page_size;
+
if (signal_test) {
if (sigsetjmp(*sigbuf, 1) != 0) {
- if (nr == lastnr) {
+ if (steps == 1 && nr == lastnr) {
fprintf(stderr, "Signal repeated\n");
return 1;
}
lastnr = nr;
if (signal_test == 1) {
- if (copy_page(uffd, nr * page_size))
- signalled++;
+ if (steps == 1) {
+ /* This is a MISSING request */
+ steps++;
+ if (copy_page(uffd, offset))
+ signalled++;
+ } else {
+ /* This is a WP request */
+ assert(steps == 2);
+ wp_range(uffd,
+ (__u64)area_dst +
+ offset,
+ page_size, false);
+ }
} else {
signalled++;
continue;
@@ -778,8 +864,13 @@ static int faulting_process(int signal_test)
fprintf(stderr,
"nr %lu memory corruption %Lu %Lu\n",
nr, count,
- count_verify[nr]), exit(1);
- }
+ count_verify[nr]);
+ }
+ /*
+ * Trigger write protection if there is by writting
+ * the same value back.
+ */
+ *area_count(area_dst, nr) = count;
}
if (signal_test)
@@ -801,6 +892,11 @@ static int faulting_process(int signal_test)
nr, count,
count_verify[nr]), exit(1);
}
+ /*
+ * Trigger write protection if there is by writting
+ * the same value back.
+ */
+ *area_count(area_dst, nr) = count;
}
if (uffd_test_ops->release_pages(area_dst))
@@ -904,6 +1000,8 @@ static int userfaultfd_zeropage_test(void)
uffdio_register.range.start = (unsigned long) area_dst;
uffdio_register.range.len = nr_pages * page_size;
uffdio_register.mode = UFFDIO_REGISTER_MODE_MISSING;
+ if (test_uffdio_wp)
+ uffdio_register.mode |= UFFDIO_REGISTER_MODE_WP;
if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register))
fprintf(stderr, "register failure\n"), exit(1);
@@ -949,6 +1047,8 @@ static int userfaultfd_events_test(void)
uffdio_register.range.start = (unsigned long) area_dst;
uffdio_register.range.len = nr_pages * page_size;
uffdio_register.mode = UFFDIO_REGISTER_MODE_MISSING;
+ if (test_uffdio_wp)
+ uffdio_register.mode |= UFFDIO_REGISTER_MODE_WP;
if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register))
fprintf(stderr, "register failure\n"), exit(1);
@@ -979,7 +1079,8 @@ static int userfaultfd_events_test(void)
return 1;
close(uffd);
- printf("userfaults: %ld\n", stats.missing_faults);
+
+ uffd_stats_report(&stats, 1);
return stats.missing_faults != nr_pages;
}
@@ -1009,6 +1110,8 @@ static int userfaultfd_sig_test(void)
uffdio_register.range.start = (unsigned long) area_dst;
uffdio_register.range.len = nr_pages * page_size;
uffdio_register.mode = UFFDIO_REGISTER_MODE_MISSING;
+ if (test_uffdio_wp)
+ uffdio_register.mode |= UFFDIO_REGISTER_MODE_WP;
if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register))
fprintf(stderr, "register failure\n"), exit(1);
@@ -1141,6 +1244,8 @@ static int userfaultfd_stress(void)
uffdio_register.range.start = (unsigned long) area_dst;
uffdio_register.range.len = nr_pages * page_size;
uffdio_register.mode = UFFDIO_REGISTER_MODE_MISSING;
+ if (test_uffdio_wp)
+ uffdio_register.mode |= UFFDIO_REGISTER_MODE_WP;
if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register)) {
fprintf(stderr, "register failure\n");
return 1;
@@ -1195,6 +1300,11 @@ static int userfaultfd_stress(void)
if (stress(uffd_stats))
return 1;
+ /* Clear all the write protections if there is any */
+ if (test_uffdio_wp)
+ wp_range(uffd, (unsigned long)area_dst,
+ nr_pages * page_size, false);
+
/* unregister */
if (ioctl(uffd, UFFDIO_UNREGISTER, &uffdio_register.range)) {
fprintf(stderr, "unregister failure\n");
@@ -1233,10 +1343,7 @@ static int userfaultfd_stress(void)
area_src_alias = area_dst_alias;
area_dst_alias = tmp_area;
- printf("userfaults:");
- for (cpu = 0; cpu < nr_cpus; cpu++)
- printf(" %lu", uffd_stats[cpu].missing_faults);
- printf("\n");
+ uffd_stats_report(uffd_stats, nr_cpus);
}
if (err)
@@ -1276,6 +1383,8 @@ static void set_test_type(const char *type)
if (!strcmp(type, "anon")) {
test_type = TEST_ANON;
uffd_test_ops = &anon_uffd_test_ops;
+ /* Only enable write-protect test for anonymous test */
+ test_uffdio_wp = true;
} else if (!strcmp(type, "hugetlb")) {
test_type = TEST_HUGETLB;
uffd_test_ops = &hugetlb_uffd_test_ops;
--
2.17.1
prev parent reply other threads:[~2019-04-26 4:56 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-26 4:51 [PATCH v4 00/27] userfaultfd: write protection support Peter Xu
2019-04-26 4:51 ` [PATCH v4 01/27] mm: gup: rename "nonblocking" to "locked" where proper Peter Xu
2019-04-26 4:51 ` [PATCH v4 02/27] mm: userfault: return VM_FAULT_RETRY on signals Peter Xu
2019-04-26 4:51 ` [PATCH v4 03/27] userfaultfd: don't retake mmap_sem to emulate NOPAGE Peter Xu
2019-04-26 4:51 ` [PATCH v4 04/27] mm: allow VM_FAULT_RETRY for multiple times Peter Xu
2019-04-26 4:51 ` [PATCH v4 05/27] mm: gup: " Peter Xu
2019-04-26 4:51 ` [PATCH v4 06/27] userfaultfd: wp: add helper for writeprotect check Peter Xu
2019-04-26 4:51 ` [PATCH v4 07/27] userfaultfd: wp: hook userfault handler to write protection fault Peter Xu
2019-04-26 4:51 ` [PATCH v4 08/27] userfaultfd: wp: add WP pagetable tracking to x86 Peter Xu
2019-04-26 4:51 ` [PATCH v4 09/27] userfaultfd: wp: userfaultfd_pte/huge_pmd_wp() helpers Peter Xu
2019-04-26 4:51 ` [PATCH v4 10/27] userfaultfd: wp: add UFFDIO_COPY_MODE_WP Peter Xu
2019-04-26 4:51 ` [PATCH v4 11/27] mm: merge parameters for change_protection() Peter Xu
2019-04-26 4:51 ` [PATCH v4 12/27] userfaultfd: wp: apply _PAGE_UFFD_WP bit Peter Xu
2019-04-26 4:51 ` [PATCH v4 13/27] mm: introduce do_wp_page_cont() Peter Xu
2019-04-26 4:51 ` [PATCH v4 14/27] userfaultfd: wp: handle COW properly for uffd-wp Peter Xu
2019-04-26 4:51 ` [PATCH v4 15/27] userfaultfd: wp: drop _PAGE_UFFD_WP properly when fork Peter Xu
2019-04-26 4:51 ` [PATCH v4 16/27] userfaultfd: wp: add pmd_swp_*uffd_wp() helpers Peter Xu
2019-04-26 4:51 ` [PATCH v4 17/27] userfaultfd: wp: support swap and page migration Peter Xu
2019-04-26 4:51 ` [PATCH v4 18/27] khugepaged: skip collapse if uffd-wp detected Peter Xu
2019-04-26 4:51 ` [PATCH v4 19/27] userfaultfd: introduce helper vma_find_uffd Peter Xu
2019-04-26 4:51 ` [PATCH v4 20/27] userfaultfd: wp: support write protection for userfault vma range Peter Xu
2019-04-26 4:51 ` [PATCH v4 21/27] userfaultfd: wp: add the writeprotect API to userfaultfd ioctl Peter Xu
2019-04-26 4:51 ` [PATCH v4 22/27] userfaultfd: wp: enabled write protection in userfaultfd API Peter Xu
2019-04-26 4:51 ` [PATCH v4 23/27] userfaultfd: wp: don't wake up when doing write protect Peter Xu
2019-04-26 4:51 ` [PATCH v4 24/27] userfaultfd: wp: UFFDIO_REGISTER_MODE_WP documentation update Peter Xu
2019-04-26 4:51 ` [PATCH v4 25/27] userfaultfd: wp: declare _UFFDIO_WRITEPROTECT conditionally Peter Xu
2019-04-26 4:51 ` [PATCH v4 26/27] userfaultfd: selftests: refactor statistics Peter Xu
2019-04-26 4:51 ` Peter Xu [this message]
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