[RFC PATCH v2 05/10] KVM: selftests: guest_memfd mmap() test when mapping is allowed

[Fuad Tabba <tabba@xxxxxxxxxx>]

Expand the guest_memfd selftests to include testing mapping guest
memory if the capability is supported, and that still checks that
memory is not mappable if the capability isn't supported.

Also, build the guest_memfd selftest for aarch64.

Signed-off-by: Fuad Tabba <tabba@xxxxxxxxxx>
---
 tools/testing/selftests/kvm/Makefile          |  1 +
 .../testing/selftests/kvm/guest_memfd_test.c  | 47 ++++++++++++++++++-
 2 files changed, 46 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
index ac280dcba996..fb63f7e956d4 100644
--- a/tools/testing/selftests/kvm/Makefile
+++ b/tools/testing/selftests/kvm/Makefile
@@ -166,6 +166,7 @@ TEST_GEN_PROGS_aarch64 += arch_timer
 TEST_GEN_PROGS_aarch64 += demand_paging_test
 TEST_GEN_PROGS_aarch64 += dirty_log_test
 TEST_GEN_PROGS_aarch64 += dirty_log_perf_test
+TEST_GEN_PROGS_aarch64 += guest_memfd_test
 TEST_GEN_PROGS_aarch64 += guest_print_test
 TEST_GEN_PROGS_aarch64 += get-reg-list
 TEST_GEN_PROGS_aarch64 += kvm_create_max_vcpus
diff --git a/tools/testing/selftests/kvm/guest_memfd_test.c b/tools/testing/selftests/kvm/guest_memfd_test.c
index ba0c8e996035..c6bb2be5b6e2 100644
--- a/tools/testing/selftests/kvm/guest_memfd_test.c
+++ b/tools/testing/selftests/kvm/guest_memfd_test.c
@@ -34,12 +34,55 @@ static void test_file_read_write(int fd)
 		    "pwrite on a guest_mem fd should fail");
 }
 
-static void test_mmap(int fd, size_t page_size)
+static void test_mmap_allowed(int fd, size_t total_size)
 {
+	size_t page_size = getpagesize();
+	char *mem;
+	int ret;
+	int i;
+
+	mem = mmap(NULL, total_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
+	TEST_ASSERT(mem != MAP_FAILED, "mmaping() guest memory should pass.");
+
+	memset(mem, 0xaa, total_size);
+	for (i = 0; i < total_size; i++)
+		TEST_ASSERT_EQ(mem[i], 0xaa);
+
+	ret = fallocate(fd, FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE, 0,
+			page_size);
+	TEST_ASSERT(!ret, "fallocate the first page should succeed");
+
+	for (i = 0; i < page_size; i++)
+		TEST_ASSERT_EQ(mem[i], 0x00);
+	for (; i < total_size; i++)
+		TEST_ASSERT_EQ(mem[i], 0xaa);
+
+	memset(mem, 0xaa, total_size);
+	for (i = 0; i < total_size; i++)
+		TEST_ASSERT_EQ(mem[i], 0xaa);
+
+	ret = munmap(mem, total_size);
+	TEST_ASSERT(!ret, "munmap should succeed");
+}
+
+static void test_mmap_denied(int fd, size_t total_size)
+{
+	size_t page_size = getpagesize();
 	char *mem;
 
 	mem = mmap(NULL, page_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
 	TEST_ASSERT_EQ(mem, MAP_FAILED);
+
+	mem = mmap(NULL, total_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
+	TEST_ASSERT_EQ(mem, MAP_FAILED);
+}
+
+static void test_mmap(int fd, size_t total_size)
+{
+	if (kvm_has_cap(KVM_CAP_GUEST_MEMFD_MAPPABLE))
+		test_mmap_allowed(fd, total_size);
+	else
+		test_mmap_denied(fd, total_size);
 }
 
 static void test_file_size(int fd, size_t page_size, size_t total_size)
@@ -190,7 +233,7 @@ int main(int argc, char *argv[])
 	fd = vm_create_guest_memfd(vm, total_size, 0);
 
 	test_file_read_write(fd);
-	test_mmap(fd, page_size);
+	test_mmap(fd, total_size);
 	test_file_size(fd, page_size, total_size);
 	test_fallocate(fd, page_size, total_size);
 	test_invalid_punch_hole(fd, page_size, total_size);
-- 
2.46.0.rc1.232.g9752f9e123-goog