KVM: selftests: aarch64: Add dirty logging tests into page_fault_test

Add some dirty logging tests into page_fault_test. Mark the data and/or
page-table memory regions for dirty logging, perform some accesses, and
check that the dirty log bits are set or clean when expected.
Signed-off-by: Ricardo Koller <ricarkol@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20221017195834.2295901-13-ricarkol@google.com

tools/testing/selftests/kvm/aarch64/page_fault_test.c

@@ -31,6 +31,11 @@ static uint64_t *guest_test_memory = (uint64_t *)TEST_GVA;
 #define CMD_SKIP_TEST				(1ULL << 1)
 #define CMD_HOLE_PT				(1ULL << 2)
 #define CMD_HOLE_DATA				(1ULL << 3)
+#define CMD_CHECK_WRITE_IN_DIRTY_LOG		(1ULL << 4)
+#define CMD_CHECK_S1PTW_WR_IN_DIRTY_LOG		(1ULL << 5)
+#define CMD_CHECK_NO_WRITE_IN_DIRTY_LOG		(1ULL << 6)
+#define CMD_CHECK_NO_S1PTW_WR_IN_DIRTY_LOG	(1ULL << 7)
+#define CMD_SET_PTE_AF				(1ULL << 8)
 
 #define PREPARE_FN_NR				10
 #define CHECK_FN_NR				10
@@ -213,6 +218,21 @@ static void guest_check_pte_af(void)
 	GUEST_ASSERT_EQ(*((uint64_t *)TEST_PTE_GVA) & PTE_AF, PTE_AF);
 }
 
+static void guest_check_write_in_dirty_log(void)
+{
+	GUEST_SYNC(CMD_CHECK_WRITE_IN_DIRTY_LOG);
+}
+
+static void guest_check_no_write_in_dirty_log(void)
+{
+	GUEST_SYNC(CMD_CHECK_NO_WRITE_IN_DIRTY_LOG);
+}
+
+static void guest_check_s1ptw_wr_in_dirty_log(void)
+{
+	GUEST_SYNC(CMD_CHECK_S1PTW_WR_IN_DIRTY_LOG);
+}
+
 static void guest_exec(void)
 {
 	int (*code)(void) = (int (*)(void))TEST_EXEC_GVA;
@@ -395,6 +415,22 @@ static bool punch_hole_in_backing_store(struct kvm_vm *vm,
 	return true;
 }
 
+static bool check_write_in_dirty_log(struct kvm_vm *vm,
+				     struct userspace_mem_region *region,
+				     uint64_t host_pg_nr)
+{
+	unsigned long *bmap;
+	bool first_page_dirty;
+	uint64_t size = region->region.memory_size;
+
+	/* getpage_size() is not always equal to vm->page_size */
+	bmap = bitmap_zalloc(size / getpagesize());
+	kvm_vm_get_dirty_log(vm, region->region.slot, bmap);
+	first_page_dirty = test_bit(host_pg_nr, bmap);
+	free(bmap);
+	return first_page_dirty;
+}
+
 /* Returns true to continue the test, and false if it should be skipped. */
 static bool handle_cmd(struct kvm_vm *vm, int cmd)
 {
@@ -411,6 +447,18 @@ static bool handle_cmd(struct kvm_vm *vm, int cmd)
 		continue_test = punch_hole_in_backing_store(vm, pt_region);
 	if (cmd & CMD_HOLE_DATA)
 		continue_test = punch_hole_in_backing_store(vm, data_region);
+	if (cmd & CMD_CHECK_WRITE_IN_DIRTY_LOG)
+		TEST_ASSERT(check_write_in_dirty_log(vm, data_region, 0),
+			    "Missing write in dirty log");
+	if (cmd & CMD_CHECK_S1PTW_WR_IN_DIRTY_LOG)
+		TEST_ASSERT(check_write_in_dirty_log(vm, pt_region, 0),
+			    "Missing s1ptw write in dirty log");
+	if (cmd & CMD_CHECK_NO_WRITE_IN_DIRTY_LOG)
+		TEST_ASSERT(!check_write_in_dirty_log(vm, data_region, 0),
+			    "Unexpected write in dirty log");
+	if (cmd & CMD_CHECK_NO_S1PTW_WR_IN_DIRTY_LOG)
+		TEST_ASSERT(!check_write_in_dirty_log(vm, pt_region, 0),
+			    "Unexpected s1ptw write in dirty log");
 
 	return continue_test;
 }
@@ -673,6 +721,19 @@ static void help(char *name)
 	.expected_events	= { .uffd_faults = _uffd_faults, },		\
 }
 
+#define TEST_DIRTY_LOG(_access, _with_af, _test_check)				\
+{										\
+	.name			= SCAT3(dirty_log, _access, _with_af),		\
+	.data_memslot_flags	= KVM_MEM_LOG_DIRTY_PAGES,			\
+	.pt_memslot_flags	= KVM_MEM_LOG_DIRTY_PAGES,			\
+	.guest_prepare		= { _PREPARE(_with_af),				\
+				    _PREPARE(_access) },			\
+	.guest_test		= _access,					\
+	.guest_test_check	= { _CHECK(_with_af), _test_check,		\
+				    guest_check_s1ptw_wr_in_dirty_log},		\
+	.expected_events	= { 0 },					\
+}
+
 static struct test_desc tests[] = {
 
 	/* Check that HW is setting the Access Flag (AF) (sanity checks). */
@@ -732,6 +793,21 @@ static struct test_desc tests[] = {
 	TEST_UFFD(guest_exec, with_af, CMD_HOLE_DATA | CMD_HOLE_PT,
 		  uffd_data_read_handler, uffd_pt_write_handler, 2),
 
+	/*
+	 * Try accesses when the data and PT memory regions are both
+	 * tracked for dirty logging.
+	 */
+	TEST_DIRTY_LOG(guest_read64, with_af, guest_check_no_write_in_dirty_log),
+	/* no_af should also lead to a PT write. */
+	TEST_DIRTY_LOG(guest_read64, no_af, guest_check_no_write_in_dirty_log),
+	TEST_DIRTY_LOG(guest_ld_preidx, with_af, guest_check_no_write_in_dirty_log),
+	TEST_DIRTY_LOG(guest_at, no_af, guest_check_no_write_in_dirty_log),
+	TEST_DIRTY_LOG(guest_exec, with_af, guest_check_no_write_in_dirty_log),
+	TEST_DIRTY_LOG(guest_write64, with_af, guest_check_write_in_dirty_log),
+	TEST_DIRTY_LOG(guest_cas, with_af, guest_check_write_in_dirty_log),
+	TEST_DIRTY_LOG(guest_dc_zva, with_af, guest_check_write_in_dirty_log),
+	TEST_DIRTY_LOG(guest_st_preidx, with_af, guest_check_write_in_dirty_log),
+
 	{ 0 }
 };