Add some userfaultfd tests into page_fault_test. Punch holes into the data and/or page-table memslots, perform some accesses, and check that the faults are taken (or not taken) when expected. Signed-off-by: Ricardo Koller <ricarkol@xxxxxxxxxx> --- .../selftests/kvm/aarch64/page_fault_test.c | 190 +++++++++++++++++- 1 file changed, 188 insertions(+), 2 deletions(-) diff --git a/tools/testing/selftests/kvm/aarch64/page_fault_test.c b/tools/testing/selftests/kvm/aarch64/page_fault_test.c index 1c7e02003753..57466d213b95 100644 --- a/tools/testing/selftests/kvm/aarch64/page_fault_test.c +++ b/tools/testing/selftests/kvm/aarch64/page_fault_test.c @@ -35,6 +35,12 @@ static uint64_t *guest_test_memory = (uint64_t *)TEST_GVA; #define PREPARE_FN_NR 10 #define CHECK_FN_NR 10 +static struct event_cnt { + int uffd_faults; + /* uffd_faults is incremented from multiple threads. */ + pthread_mutex_t uffd_faults_mutex; +} events; + struct test_desc { const char *name; uint64_t mem_mark_cmd; @@ -42,11 +48,14 @@ struct test_desc { bool (*guest_prepare[PREPARE_FN_NR])(void); void (*guest_test)(void); void (*guest_test_check[CHECK_FN_NR])(void); + uffd_handler_t uffd_pt_handler; + uffd_handler_t uffd_data_handler; void (*dabt_handler)(struct ex_regs *regs); void (*iabt_handler)(struct ex_regs *regs); uint32_t pt_memslot_flags; uint32_t data_memslot_flags; bool skip; + struct event_cnt expected_events; }; struct test_params { @@ -263,7 +272,110 @@ static void no_iabt_handler(struct ex_regs *regs) GUEST_ASSERT_1(false, regs->pc); } +static struct uffd_args { + char *copy; + void *hva; + uint64_t paging_size; +} pt_args, data_args; + /* Returns true to continue the test, and false if it should be skipped. */ +static int uffd_generic_handler(int uffd_mode, int uffd, + struct uffd_msg *msg, struct uffd_args *args, + bool expect_write) +{ + uint64_t addr = msg->arg.pagefault.address; + uint64_t flags = msg->arg.pagefault.flags; + struct uffdio_copy copy; + int ret; + + TEST_ASSERT(uffd_mode == UFFDIO_REGISTER_MODE_MISSING, + "The only expected UFFD mode is MISSING"); + ASSERT_EQ(!!(flags & UFFD_PAGEFAULT_FLAG_WRITE), expect_write); + ASSERT_EQ(addr, (uint64_t)args->hva); + + pr_debug("uffd fault: addr=%p write=%d\n", + (void *)addr, !!(flags & UFFD_PAGEFAULT_FLAG_WRITE)); + + copy.src = (uint64_t)args->copy; + copy.dst = addr; + copy.len = args->paging_size; + copy.mode = 0; + + ret = ioctl(uffd, UFFDIO_COPY, ©); + if (ret == -1) { + pr_info("Failed UFFDIO_COPY in 0x%lx with errno: %d\n", + addr, errno); + return ret; + } + + pthread_mutex_lock(&events.uffd_faults_mutex); + events.uffd_faults += 1; + pthread_mutex_unlock(&events.uffd_faults_mutex); + return 0; +} + +static int uffd_pt_write_handler(int mode, int uffd, struct uffd_msg *msg) +{ + return uffd_generic_handler(mode, uffd, msg, &pt_args, true); +} + +static int uffd_data_write_handler(int mode, int uffd, struct uffd_msg *msg) +{ + return uffd_generic_handler(mode, uffd, msg, &data_args, true); +} + +static int uffd_data_read_handler(int mode, int uffd, struct uffd_msg *msg) +{ + return uffd_generic_handler(mode, uffd, msg, &data_args, false); +} + +static void setup_uffd_args(struct userspace_mem_region *region, + struct uffd_args *args) +{ + args->hva = (void *)region->region.userspace_addr; + args->paging_size = region->region.memory_size; + + args->copy = malloc(args->paging_size); + TEST_ASSERT(args->copy, "Failed to allocate data copy."); + memcpy(args->copy, args->hva, args->paging_size); +} + +static void setup_uffd(struct kvm_vm *vm, struct test_params *p, + struct uffd_desc **pt_uffd, struct uffd_desc **data_uffd) +{ + struct test_desc *test = p->test_desc; + + setup_uffd_args(vm_get_mem_region(vm, MEM_REGION_PT), &pt_args); + setup_uffd_args(vm_get_mem_region(vm, MEM_REGION_DATA), &data_args); + + *pt_uffd = NULL; + if (test->uffd_pt_handler) + *pt_uffd = uffd_setup_demand_paging( + UFFDIO_REGISTER_MODE_MISSING, 0, + pt_args.hva, pt_args.paging_size, + test->uffd_pt_handler); + + *data_uffd = NULL; + if (test->uffd_data_handler) + *data_uffd = uffd_setup_demand_paging( + UFFDIO_REGISTER_MODE_MISSING, 0, + data_args.hva, data_args.paging_size, + test->uffd_data_handler); +} + +static void free_uffd(struct test_desc *test, struct uffd_desc *pt_uffd, + struct uffd_desc *data_uffd) +{ + if (test->uffd_pt_handler) + uffd_stop_demand_paging(pt_uffd); + if (test->uffd_data_handler) + uffd_stop_demand_paging(data_uffd); + + free(pt_args.copy); + free(data_args.copy); +} + +/* Returns false if the test should be skipped. */ static bool punch_hole_in_memslot(struct kvm_vm *vm, struct userspace_mem_region *region) { @@ -431,6 +543,11 @@ static struct kvm_vm_mem_params setup_memslots(enum vm_guest_mode mode, return mem_params; } +static void check_event_counts(struct test_desc *test) +{ + ASSERT_EQ(test->expected_events.uffd_faults, events.uffd_faults); +} + static void print_test_banner(enum vm_guest_mode mode, struct test_params *p) { struct test_desc *test = p->test_desc; @@ -441,12 +558,17 @@ static void print_test_banner(enum vm_guest_mode mode, struct test_params *p) vm_mem_backing_src_alias(p->src_type)->name); } +static void reset_event_counts(void) +{ + memset(&events, 0, sizeof(events)); +} + /* * This function either succeeds, skips the test (after setting test->skip), or * fails with a TEST_FAIL that aborts all tests. */ static void vcpu_run_loop(struct kvm_vm *vm, struct kvm_vcpu *vcpu, - struct test_desc *test) + struct test_desc *test) { struct ucall uc; @@ -481,6 +603,7 @@ static void run_test(enum vm_guest_mode mode, void *arg) struct test_desc *test = p->test_desc; struct kvm_vm *vm; struct kvm_vcpu *vcpu; + struct uffd_desc *pt_uffd, *data_uffd; struct kvm_vm_mem_params mem_params; print_test_banner(mode, p); @@ -494,7 +617,16 @@ static void run_test(enum vm_guest_mode mode, void *arg) ucall_init(vm, NULL); + reset_event_counts(); + + /* + * Set some code in the data memslot for the guest to execute (only + * applicable to the EXEC tests). This has to be done before + * setup_uffd() as that function copies the memslot data for the uffd + * handler. + */ load_exec_code_for_test(vm); + setup_uffd(vm, p, &pt_uffd, &data_uffd); setup_abort_handlers(vm, vcpu, test); vcpu_args_set(vcpu, 1, test); @@ -502,6 +634,14 @@ static void run_test(enum vm_guest_mode mode, void *arg) ucall_uninit(vm); kvm_vm_free(vm); + free_uffd(test, pt_uffd, data_uffd); + + /* + * Make sure we check the events after the uffd threads have exited, + * which means they updated their respective event counters. + */ + if (!test->skip) + check_event_counts(test); } static void help(char *name) @@ -517,6 +657,7 @@ static void help(char *name) #define SNAME(s) #s #define SCAT2(a, b) SNAME(a ## _ ## b) #define SCAT3(a, b, c) SCAT2(a, SCAT2(b, c)) +#define SCAT4(a, b, c, d) SCAT2(a, SCAT3(b, c, d)) #define _CHECK(_test) _CHECK_##_test #define _PREPARE(_test) _PREPARE_##_test @@ -535,7 +676,7 @@ static void help(char *name) #define _CHECK_with_af guest_check_pte_af #define _CHECK_no_af NULL -/* Performs an access and checks that no faults were triggered. */ +/* Performs an access and checks that no faults (no events) were triggered. */ #define TEST_ACCESS(_access, _with_af, _mark_cmd) \ { \ .name = SCAT3(_access, _with_af, #_mark_cmd), \ @@ -544,6 +685,21 @@ static void help(char *name) .mem_mark_cmd = _mark_cmd, \ .guest_test = _access, \ .guest_test_check = { _CHECK(_with_af) }, \ + .expected_events = { 0 }, \ +} + +#define TEST_UFFD(_access, _with_af, _mark_cmd, \ + _uffd_data_handler, _uffd_pt_handler, _uffd_faults) \ +{ \ + .name = SCAT4(uffd, _access, _with_af, #_mark_cmd), \ + .guest_prepare = { _PREPARE(_with_af), \ + _PREPARE(_access) }, \ + .guest_test = _access, \ + .mem_mark_cmd = _mark_cmd, \ + .guest_test_check = { _CHECK(_with_af) }, \ + .uffd_data_handler = _uffd_data_handler, \ + .uffd_pt_handler = _uffd_pt_handler, \ + .expected_events = { .uffd_faults = _uffd_faults, }, \ } static struct test_desc tests[] = { @@ -569,6 +725,36 @@ static struct test_desc tests[] = { TEST_ACCESS(guest_at, no_af, CMD_HOLE_DATA), TEST_ACCESS(guest_dc_zva, no_af, CMD_HOLE_DATA), + /* + * Punch holes in the test and PT memslots and mark them for + * userfaultfd handling. This should result in 2 faults: the test + * access and its respective S1 page table walk (S1PTW). + */ + TEST_UFFD(guest_read64, with_af, CMD_HOLE_DATA | CMD_HOLE_PT, + uffd_data_read_handler, uffd_pt_write_handler, 2), + /* no_af should also lead to a PT write. */ + TEST_UFFD(guest_read64, no_af, CMD_HOLE_DATA | CMD_HOLE_PT, + uffd_data_read_handler, uffd_pt_write_handler, 2), + /* Note how that cas invokes the read handler. */ + TEST_UFFD(guest_cas, with_af, CMD_HOLE_DATA | CMD_HOLE_PT, + uffd_data_read_handler, uffd_pt_write_handler, 2), + /* + * Can't test guest_at with_af as it's IMPDEF whether the AF is set. + * The S1PTW fault should still be marked as a write. + */ + TEST_UFFD(guest_at, no_af, CMD_HOLE_DATA | CMD_HOLE_PT, + uffd_data_read_handler, uffd_pt_write_handler, 1), + TEST_UFFD(guest_ld_preidx, with_af, CMD_HOLE_DATA | CMD_HOLE_PT, + uffd_data_read_handler, uffd_pt_write_handler, 2), + TEST_UFFD(guest_write64, with_af, CMD_HOLE_DATA | CMD_HOLE_PT, + uffd_data_write_handler, uffd_pt_write_handler, 2), + TEST_UFFD(guest_dc_zva, with_af, CMD_HOLE_DATA | CMD_HOLE_PT, + uffd_data_write_handler, uffd_pt_write_handler, 2), + TEST_UFFD(guest_st_preidx, with_af, CMD_HOLE_DATA | CMD_HOLE_PT, + uffd_data_write_handler, uffd_pt_write_handler, 2), + TEST_UFFD(guest_exec, with_af, CMD_HOLE_DATA | CMD_HOLE_PT, + uffd_data_read_handler, uffd_pt_write_handler, 2), + { 0 } }; -- 2.37.2.789.g6183377224-goog