[PATCH v8 13/13] KVM: guest_memfd: selftests: guest_memfd mmap() test when mapping is allowed

[Fuad Tabba <tabba@google.com>]

Expand the guest_memfd selftests to include testing mapping guest
memory for VM types that support it.

Also, build the guest_memfd selftest for arm64.

Signed-off-by: Fuad Tabba <tabba@google.com>
---
 tools/testing/selftests/kvm/Makefile.kvm      |  1 +
 .../testing/selftests/kvm/guest_memfd_test.c  | 75 +++++++++++++++++--
 2 files changed, 70 insertions(+), 6 deletions(-)

diff --git a/tools/testing/selftests/kvm/Makefile.kvm b/tools/testing/selftests/kvm/Makefile.kvm
index f62b0a5aba35..ccf95ed037c3 100644
--- a/tools/testing/selftests/kvm/Makefile.kvm
+++ b/tools/testing/selftests/kvm/Makefile.kvm
@@ -163,6 +163,7 @@ TEST_GEN_PROGS_arm64 += access_tracking_perf_test
 TEST_GEN_PROGS_arm64 += arch_timer
 TEST_GEN_PROGS_arm64 += coalesced_io_test
 TEST_GEN_PROGS_arm64 += dirty_log_perf_test
+TEST_GEN_PROGS_arm64 += guest_memfd_test
 TEST_GEN_PROGS_arm64 += get-reg-list
 TEST_GEN_PROGS_arm64 += memslot_modification_stress_test
 TEST_GEN_PROGS_arm64 += memslot_perf_test
diff --git a/tools/testing/selftests/kvm/guest_memfd_test.c b/tools/testing/selftests/kvm/guest_memfd_test.c
index ce687f8d248f..bd35b56c90dc 100644
--- a/tools/testing/selftests/kvm/guest_memfd_test.c
+++ b/tools/testing/selftests/kvm/guest_memfd_test.c
@@ -34,12 +34,48 @@ 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();
+	const char val = 0xaa;
+	char *mem;
+	size_t i;
+	int ret;
+
+	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, val, total_size);
+	for (i = 0; i < total_size; i++)
+		TEST_ASSERT_EQ(mem[i], val);
+
+	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], val);
+
+	memset(mem, val, total_size);
+	for (i = 0; i < total_size; i++)
+		TEST_ASSERT_EQ(mem[i], val);
+
+	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_file_size(int fd, size_t page_size, size_t total_size)
@@ -170,19 +206,27 @@ static void test_create_guest_memfd_multiple(struct kvm_vm *vm)
 	close(fd1);
 }
 
-int main(int argc, char *argv[])
+unsigned long get_shared_type(void)
 {
-	size_t page_size;
+#ifdef __x86_64__
+	return KVM_X86_SW_PROTECTED_VM;
+#endif
+	return 0;
+}
+
+void test_vm_type(unsigned long type, bool is_shared)
+{
+	struct kvm_vm *vm;
 	size_t total_size;
+	size_t page_size;
 	int fd;
-	struct kvm_vm *vm;
 
 	TEST_REQUIRE(kvm_has_cap(KVM_CAP_GUEST_MEMFD));
 
 	page_size = getpagesize();
 	total_size = page_size * 4;
 
-	vm = vm_create_barebones();
+	vm = vm_create_barebones_type(type);
 
 	test_create_guest_memfd_invalid(vm);
 	test_create_guest_memfd_multiple(vm);
@@ -190,10 +234,29 @@ 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);
+
+	if (is_shared)
+		test_mmap_allowed(fd, total_size);
+	else
+		test_mmap_denied(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);
 
 	close(fd);
+	kvm_vm_release(vm);
+}
+
+int main(int argc, char *argv[])
+{
+#ifndef __aarch64__
+	/* For now, arm64 only supports shared guest memory. */
+	test_vm_type(VM_TYPE_DEFAULT, false);
+#endif
+
+	if (kvm_has_cap(KVM_CAP_GMEM_SHARED_MEM))
+		test_vm_type(get_shared_type(), true);
+
+	return 0;
 }
-- 
2.49.0.901.g37484f566f-goog