@@ -3,6 +3,7 @@
/aarch64/debug-exceptions
/aarch64/get-reg-list
/aarch64/hypercalls
+/aarch64/page_fault_test
/aarch64/psci_test
/aarch64/vcpu_width_config
/aarch64/vgic_init
@@ -149,6 +149,7 @@ TEST_GEN_PROGS_aarch64 += aarch64/arch_timer
TEST_GEN_PROGS_aarch64 += aarch64/debug-exceptions
TEST_GEN_PROGS_aarch64 += aarch64/get-reg-list
TEST_GEN_PROGS_aarch64 += aarch64/hypercalls
+TEST_GEN_PROGS_aarch64 += aarch64/page_fault_test
TEST_GEN_PROGS_aarch64 += aarch64/psci_test
TEST_GEN_PROGS_aarch64 += aarch64/vcpu_width_config
TEST_GEN_PROGS_aarch64 += aarch64/vgic_init
new file mode 100644
@@ -0,0 +1,595 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * page_fault_test.c - Test stage 2 faults.
+ *
+ * This test tries different combinations of guest accesses (e.g., write,
+ * S1PTW), backing source type (e.g., anon) and types of faults (e.g., read on
+ * hugetlbfs with a hole). It checks that the expected handling method is
+ * called (e.g., uffd faults with the right address and write/read flag).
+ */
+
+#define _GNU_SOURCE
+#include <linux/bitmap.h>
+#include <fcntl.h>
+#include <test_util.h>
+#include <kvm_util.h>
+#include <processor.h>
+#include <asm/sysreg.h>
+#include <linux/bitfield.h>
+#include "guest_modes.h"
+#include "userfaultfd_util.h"
+
+/* Guest virtual addresses that point to the test page and its PTE. */
+#define TEST_GVA 0xc0000000
+#define TEST_EXEC_GVA (TEST_GVA + 0x8)
+#define TEST_PTE_GVA 0xb0000000
+#define TEST_DATA 0x0123456789ABCDEF
+
+static uint64_t *guest_test_memory = (uint64_t *)TEST_GVA;
+
+#define CMD_NONE (0)
+#define CMD_SKIP_TEST (1ULL << 1)
+#define CMD_HOLE_PT (1ULL << 2)
+#define CMD_HOLE_DATA (1ULL << 3)
+
+#define PREPARE_FN_NR 10
+#define CHECK_FN_NR 10
+
+struct test_desc {
+ const char *name;
+ uint64_t mem_mark_cmd;
+ /* Skip the test if any prepare function returns false */
+ bool (*guest_prepare[PREPARE_FN_NR])(void);
+ void (*guest_test)(void);
+ void (*guest_test_check[CHECK_FN_NR])(void);
+ 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 test_params {
+ enum vm_mem_backing_src_type src_type;
+ struct test_desc *test_desc;
+};
+
+static inline void flush_tlb_page(uint64_t vaddr)
+{
+ uint64_t page = vaddr >> 12;
+
+ dsb(ishst);
+ asm volatile("tlbi vaae1is, %0" :: "r" (page));
+ dsb(ish);
+ isb();
+}
+
+static void guest_write64(void)
+{
+ uint64_t val;
+
+ WRITE_ONCE(*guest_test_memory, TEST_DATA);
+ val = READ_ONCE(*guest_test_memory);
+ GUEST_ASSERT_EQ(val, TEST_DATA);
+}
+
+/* Check the system for atomic instructions. */
+static bool guest_check_lse(void)
+{
+ uint64_t isar0 = read_sysreg(id_aa64isar0_el1);
+ uint64_t atomic;
+
+ atomic = FIELD_GET(ARM64_FEATURE_MASK(ID_AA64ISAR0_ATOMICS), isar0);
+ return atomic >= 2;
+}
+
+static bool guest_check_dc_zva(void)
+{
+ uint64_t dczid = read_sysreg(dczid_el0);
+ uint64_t dzp = FIELD_GET(ARM64_FEATURE_MASK(DCZID_DZP), dczid);
+
+ return dzp == 0;
+}
+
+/* Compare and swap instruction. */
+static void guest_cas(void)
+{
+ uint64_t val;
+
+ GUEST_ASSERT(guest_check_lse());
+ asm volatile(".arch_extension lse\n"
+ "casal %0, %1, [%2]\n"
+ :: "r" (0), "r" (TEST_DATA), "r" (guest_test_memory));
+ val = READ_ONCE(*guest_test_memory);
+ GUEST_ASSERT_EQ(val, TEST_DATA);
+}
+
+static void guest_read64(void)
+{
+ uint64_t val;
+
+ val = READ_ONCE(*guest_test_memory);
+ GUEST_ASSERT_EQ(val, 0);
+}
+
+/* Address translation instruction */
+static void guest_at(void)
+{
+ uint64_t par;
+
+ asm volatile("at s1e1r, %0" :: "r" (guest_test_memory));
+ par = read_sysreg(par_el1);
+ isb();
+
+ /* Bit 1 indicates whether the AT was successful */
+ GUEST_ASSERT_EQ(par & 1, 0);
+}
+
+/*
+ * The size of the block written by "dc zva" is guaranteed to be between (2 <<
+ * 0) and (2 << 9), which is safe in our case as we need the write to happen
+ * for at least a word, and not more than a page.
+ */
+static void guest_dc_zva(void)
+{
+ uint16_t val;
+
+ asm volatile("dc zva, %0" :: "r" (guest_test_memory));
+ dsb(ish);
+ val = READ_ONCE(*guest_test_memory);
+ GUEST_ASSERT_EQ(val, 0);
+}
+
+/*
+ * Pre-indexing loads and stores don't have a valid syndrome (ESR_EL2.ISV==0).
+ * And that's special because KVM must take special care with those: they
+ * should still count as accesses for dirty logging or user-faulting, but
+ * should be handled differently on mmio.
+ */
+static void guest_ld_preidx(void)
+{
+ uint64_t val;
+ uint64_t addr = TEST_GVA - 8;
+
+ /*
+ * This ends up accessing "TEST_GVA + 8 - 8", where "TEST_GVA - 8" is
+ * in a gap between memslots not backing by anything.
+ */
+ asm volatile("ldr %0, [%1, #8]!"
+ : "=r" (val), "+r" (addr));
+ GUEST_ASSERT_EQ(val, 0);
+ GUEST_ASSERT_EQ(addr, TEST_GVA);
+}
+
+static void guest_st_preidx(void)
+{
+ uint64_t val = TEST_DATA;
+ uint64_t addr = TEST_GVA - 8;
+
+ asm volatile("str %0, [%1, #8]!"
+ : "+r" (val), "+r" (addr));
+
+ GUEST_ASSERT_EQ(addr, TEST_GVA);
+ val = READ_ONCE(*guest_test_memory);
+}
+
+static bool guest_set_ha(void)
+{
+ uint64_t mmfr1 = read_sysreg(id_aa64mmfr1_el1);
+ uint64_t hadbs, tcr;
+
+ /* Skip if HA is not supported. */
+ hadbs = FIELD_GET(ARM64_FEATURE_MASK(ID_AA64MMFR1_HADBS), mmfr1);
+ if (hadbs == 0)
+ return false;
+
+ tcr = read_sysreg(tcr_el1) | TCR_EL1_HA;
+ write_sysreg(tcr, tcr_el1);
+ isb();
+
+ return true;
+}
+
+static bool guest_clear_pte_af(void)
+{
+ *((uint64_t *)TEST_PTE_GVA) &= ~PTE_AF;
+ flush_tlb_page(TEST_GVA);
+
+ return true;
+}
+
+static void guest_check_pte_af(void)
+{
+ dsb(ish);
+ GUEST_ASSERT_EQ(*((uint64_t *)TEST_PTE_GVA) & PTE_AF, PTE_AF);
+}
+
+static void guest_exec(void)
+{
+ int (*code)(void) = (int (*)(void))TEST_EXEC_GVA;
+ int ret;
+
+ ret = code();
+ GUEST_ASSERT_EQ(ret, 0x77);
+}
+
+static bool guest_prepare(struct test_desc *test)
+{
+ bool (*prepare_fn)(void);
+ int i;
+
+ for (i = 0; i < PREPARE_FN_NR; i++) {
+ prepare_fn = test->guest_prepare[i];
+ if (prepare_fn && !prepare_fn())
+ return false;
+ }
+
+ return true;
+}
+
+static void guest_test_check(struct test_desc *test)
+{
+ void (*check_fn)(void);
+ int i;
+
+ for (i = 0; i < CHECK_FN_NR; i++) {
+ check_fn = test->guest_test_check[i];
+ if (check_fn)
+ check_fn();
+ }
+}
+
+static void guest_code(struct test_desc *test)
+{
+ if (!guest_prepare(test))
+ GUEST_SYNC(CMD_SKIP_TEST);
+
+ GUEST_SYNC(test->mem_mark_cmd);
+
+ if (test->guest_test)
+ test->guest_test();
+
+ guest_test_check(test);
+ GUEST_DONE();
+}
+
+static void no_dabt_handler(struct ex_regs *regs)
+{
+ GUEST_ASSERT_1(false, read_sysreg(far_el1));
+}
+
+static void no_iabt_handler(struct ex_regs *regs)
+{
+ GUEST_ASSERT_1(false, regs->pc);
+}
+
+/* Returns true to continue the test, and false if it should be skipped. */
+static bool punch_hole_in_memslot(struct kvm_vm *vm,
+ struct userspace_mem_region *region)
+{
+ void *hva = (void *)region->region.userspace_addr;
+ uint64_t paging_size = region->region.memory_size;
+ int ret, fd = region->fd;
+
+ if (fd != -1) {
+ ret = fallocate(fd, FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE,
+ 0, paging_size);
+ TEST_ASSERT(ret == 0, "fallocate failed, errno: %d\n", errno);
+ } else {
+ if (is_backing_src_hugetlb(region->backing_src_type))
+ return false;
+
+ ret = madvise(hva, paging_size, MADV_DONTNEED);
+ TEST_ASSERT(ret == 0, "madvise failed, errno: %d\n", errno);
+ }
+
+ return true;
+}
+
+/* Returns true to continue the test, and false if it should be skipped. */
+static bool handle_cmd(struct kvm_vm *vm, int cmd)
+{
+ struct userspace_mem_region *data_region, *pt_region;
+ bool continue_test = true;
+
+ data_region = vm_get_mem_region(vm, MEM_REGION_TEST_DATA);
+ pt_region = vm_get_mem_region(vm, MEM_REGION_PT);
+
+ if (cmd == CMD_SKIP_TEST)
+ continue_test = false;
+
+ if (cmd & CMD_HOLE_PT)
+ continue_test = punch_hole_in_memslot(vm, pt_region);
+ if (cmd & CMD_HOLE_DATA)
+ continue_test = punch_hole_in_memslot(vm, data_region);
+
+ return continue_test;
+}
+
+typedef uint32_t aarch64_insn_t;
+extern aarch64_insn_t __exec_test[2];
+
+void noinline __return_0x77(void)
+{
+ asm volatile("__exec_test: mov x0, #0x77\n"
+ "ret\n");
+}
+
+/*
+ * Note that this function runs on the host before the test VM starts: there's
+ * no need to sync the D$ and I$ caches.
+ */
+static void load_exec_code_for_test(struct kvm_vm *vm)
+{
+ uint64_t *code;
+ struct userspace_mem_region *region;
+ void *hva;
+
+ region = vm_get_mem_region(vm, MEM_REGION_TEST_DATA);
+ hva = (void *)region->region.userspace_addr;
+
+ assert(TEST_EXEC_GVA > TEST_GVA);
+ code = hva + TEST_EXEC_GVA - TEST_GVA;
+ memcpy(code, __exec_test, sizeof(__exec_test));
+}
+
+static void setup_abort_handlers(struct kvm_vm *vm, struct kvm_vcpu *vcpu,
+ struct test_desc *test)
+{
+ vm_init_descriptor_tables(vm);
+ vcpu_init_descriptor_tables(vcpu);
+
+ vm_install_sync_handler(vm, VECTOR_SYNC_CURRENT,
+ ESR_EC_DABT, no_dabt_handler);
+ vm_install_sync_handler(vm, VECTOR_SYNC_CURRENT,
+ ESR_EC_IABT, no_iabt_handler);
+}
+
+static void setup_gva_maps(struct kvm_vm *vm)
+{
+ struct userspace_mem_region *region;
+ uint64_t pte_gpa;
+
+ region = vm_get_mem_region(vm, MEM_REGION_TEST_DATA);
+ /* Map TEST_GVA first. This will install a new PTE. */
+ virt_pg_map(vm, TEST_GVA, region->region.guest_phys_addr);
+ /* Then map TEST_PTE_GVA to the above PTE. */
+ pte_gpa = addr_hva2gpa(vm, virt_get_pte_hva(vm, TEST_GVA));
+ virt_pg_map(vm, TEST_PTE_GVA, pte_gpa);
+}
+
+enum pf_test_memslots {
+ CODE_AND_DATA_MEMSLOT,
+ PAGE_TABLE_MEMSLOT,
+ TEST_DATA_MEMSLOT,
+};
+
+/*
+ * Create a memslot for code and data at pfn=0, and test-data and PT ones
+ * at max_gfn.
+ */
+static void setup_memslots(struct kvm_vm *vm, struct test_params *p)
+{
+ uint64_t backing_src_pagesz = get_backing_src_pagesz(p->src_type);
+ uint64_t guest_page_size = vm->page_size;
+ uint64_t max_gfn = vm_compute_max_gfn(vm);
+ /* Enough for 2M of code when using 4K guest pages. */
+ uint64_t code_npages = 512;
+ uint64_t pt_size, data_size, data_gpa;
+
+ /*
+ * This test requires 1 pgd, 2 pud, 4 pmd, and 6 pte pages when using
+ * VM_MODE_P48V48_4K. Note that the .text takes ~1.6MBs. That's 13
+ * pages. VM_MODE_P48V48_4K is the mode with most PT pages; let's use
+ * twice that just in case.
+ */
+ pt_size = 26 * guest_page_size;
+
+ /* memslot sizes and gpa's must be aligned to the backing page size */
+ pt_size = align_up(pt_size, backing_src_pagesz);
+ data_size = align_up(guest_page_size, backing_src_pagesz);
+ data_gpa = (max_gfn * guest_page_size) - data_size;
+ data_gpa = align_down(data_gpa, backing_src_pagesz);
+
+ vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS, 0,
+ CODE_AND_DATA_MEMSLOT, code_npages, 0);
+ vm->memslots[MEM_REGION_CODE] = CODE_AND_DATA_MEMSLOT;
+ vm->memslots[MEM_REGION_DATA] = CODE_AND_DATA_MEMSLOT;
+
+ vm_userspace_mem_region_add(vm, p->src_type, data_gpa - pt_size,
+ PAGE_TABLE_MEMSLOT, pt_size / guest_page_size,
+ p->test_desc->pt_memslot_flags);
+ vm->memslots[MEM_REGION_PT] = PAGE_TABLE_MEMSLOT;
+
+ vm_userspace_mem_region_add(vm, p->src_type, data_gpa, TEST_DATA_MEMSLOT,
+ data_size / guest_page_size,
+ p->test_desc->data_memslot_flags);
+ vm->memslots[MEM_REGION_TEST_DATA] = TEST_DATA_MEMSLOT;
+}
+
+static void print_test_banner(enum vm_guest_mode mode, struct test_params *p)
+{
+ struct test_desc *test = p->test_desc;
+
+ pr_debug("Test: %s\n", test->name);
+ pr_debug("Testing guest mode: %s\n", vm_guest_mode_string(mode));
+ pr_debug("Testing memory backing src type: %s\n",
+ vm_mem_backing_src_alias(p->src_type)->name);
+}
+
+/*
+ * 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 ucall uc;
+
+ for (;;) {
+ vcpu_run(vcpu);
+
+ switch (get_ucall(vcpu, &uc)) {
+ case UCALL_SYNC:
+ if (!handle_cmd(vm, uc.args[1])) {
+ test->skip = true;
+ goto done;
+ }
+ break;
+ case UCALL_ABORT:
+ REPORT_GUEST_ASSERT_2(uc, "values: %#lx, %#lx");
+ break;
+ case UCALL_DONE:
+ goto done;
+ default:
+ TEST_FAIL("Unknown ucall %lu", uc.cmd);
+ }
+ }
+
+done:
+ pr_debug(test->skip ? "Skipped.\n" : "Done.\n");
+ return;
+}
+
+static void run_test(enum vm_guest_mode mode, void *arg)
+{
+ struct test_params *p = (struct test_params *)arg;
+ struct test_desc *test = p->test_desc;
+ struct kvm_vm *vm;
+ struct kvm_vcpu *vcpu;
+
+ print_test_banner(mode, p);
+
+ vm = ____vm_create(mode);
+ setup_memslots(vm, p);
+ kvm_vm_elf_load(vm, program_invocation_name);
+ vcpu = vm_vcpu_add(vm, 0, guest_code);
+
+ setup_gva_maps(vm);
+
+ ucall_init(vm, NULL);
+
+ load_exec_code_for_test(vm);
+ setup_abort_handlers(vm, vcpu, test);
+ vcpu_args_set(vcpu, 1, test);
+
+ vcpu_run_loop(vm, vcpu, test);
+
+ ucall_uninit(vm);
+ kvm_vm_free(vm);
+}
+
+static void help(char *name)
+{
+ puts("");
+ printf("usage: %s [-h] [-s mem-type]\n", name);
+ puts("");
+ guest_modes_help();
+ backing_src_help("-s");
+ puts("");
+}
+
+#define SNAME(s) #s
+#define SCAT2(a, b) SNAME(a ## _ ## b)
+#define SCAT3(a, b, c) SCAT2(a, SCAT2(b, c))
+
+#define _CHECK(_test) _CHECK_##_test
+#define _PREPARE(_test) _PREPARE_##_test
+#define _PREPARE_guest_read64 NULL
+#define _PREPARE_guest_ld_preidx NULL
+#define _PREPARE_guest_write64 NULL
+#define _PREPARE_guest_st_preidx NULL
+#define _PREPARE_guest_exec NULL
+#define _PREPARE_guest_at NULL
+#define _PREPARE_guest_dc_zva guest_check_dc_zva
+#define _PREPARE_guest_cas guest_check_lse
+
+/* With or without access flag checks */
+#define _PREPARE_with_af guest_set_ha, guest_clear_pte_af
+#define _PREPARE_no_af NULL
+#define _CHECK_with_af guest_check_pte_af
+#define _CHECK_no_af NULL
+
+/* Performs an access and checks that no faults were triggered. */
+#define TEST_ACCESS(_access, _with_af, _mark_cmd) \
+{ \
+ .name = SCAT3(_access, _with_af, #_mark_cmd), \
+ .guest_prepare = { _PREPARE(_with_af), \
+ _PREPARE(_access) }, \
+ .mem_mark_cmd = _mark_cmd, \
+ .guest_test = _access, \
+ .guest_test_check = { _CHECK(_with_af) }, \
+}
+
+static struct test_desc tests[] = {
+
+ /* Check that HW is setting the Access Flag (AF) (sanity checks). */
+ TEST_ACCESS(guest_read64, with_af, CMD_NONE),
+ TEST_ACCESS(guest_ld_preidx, with_af, CMD_NONE),
+ TEST_ACCESS(guest_cas, with_af, CMD_NONE),
+ TEST_ACCESS(guest_write64, with_af, CMD_NONE),
+ TEST_ACCESS(guest_st_preidx, with_af, CMD_NONE),
+ TEST_ACCESS(guest_dc_zva, with_af, CMD_NONE),
+ TEST_ACCESS(guest_exec, with_af, CMD_NONE),
+
+ /*
+ * Accessing a hole in the data memslot (punched with fallocate or
+ * madvise) shouldn't fault (more sanity checks).
+ */
+ TEST_ACCESS(guest_read64, no_af, CMD_HOLE_DATA),
+ TEST_ACCESS(guest_cas, no_af, CMD_HOLE_DATA),
+ TEST_ACCESS(guest_ld_preidx, no_af, CMD_HOLE_DATA),
+ TEST_ACCESS(guest_write64, no_af, CMD_HOLE_DATA),
+ TEST_ACCESS(guest_st_preidx, no_af, CMD_HOLE_DATA),
+ TEST_ACCESS(guest_at, no_af, CMD_HOLE_DATA),
+ TEST_ACCESS(guest_dc_zva, no_af, CMD_HOLE_DATA),
+
+ { 0 }
+};
+
+static void for_each_test_and_guest_mode(
+ void (*func)(enum vm_guest_mode m, void *a),
+ enum vm_mem_backing_src_type src_type)
+{
+ struct test_desc *t;
+
+ for (t = &tests[0]; t->name; t++) {
+ if (t->skip)
+ continue;
+
+ struct test_params p = {
+ .src_type = src_type,
+ .test_desc = t,
+ };
+
+ for_each_guest_mode(run_test, &p);
+ }
+}
+
+int main(int argc, char *argv[])
+{
+ enum vm_mem_backing_src_type src_type;
+ int opt;
+
+ setbuf(stdout, NULL);
+
+ src_type = DEFAULT_VM_MEM_SRC;
+
+ while ((opt = getopt(argc, argv, "hm:s:")) != -1) {
+ switch (opt) {
+ case 'm':
+ guest_modes_cmdline(optarg);
+ break;
+ case 's':
+ src_type = parse_backing_src_type(optarg);
+ break;
+ case 'h':
+ default:
+ help(argv[0]);
+ exit(0);
+ }
+ }
+
+ for_each_test_and_guest_mode(run_test, src_type);
+ return 0;
+}
@@ -105,11 +105,19 @@ enum {
#define ESR_EC_MASK (ESR_EC_NUM - 1)
#define ESR_EC_SVC64 0x15
+#define ESR_EC_IABT 0x21
+#define ESR_EC_DABT 0x25
#define ESR_EC_HW_BP_CURRENT 0x31
#define ESR_EC_SSTEP_CURRENT 0x33
#define ESR_EC_WP_CURRENT 0x35
#define ESR_EC_BRK_INS 0x3c
+/* Access flag */
+#define PTE_AF (1ULL << 10)
+
+/* Access flag update enable/disable */
+#define TCR_EL1_HA (1ULL << 39)
+
void aarch64_get_supported_page_sizes(uint32_t ipa,
bool *ps4k, bool *ps16k, bool *ps64k);
Add a new test for stage 2 faults when using different combinations of guest accesses (e.g., write, S1PTW), backing source type (e.g., anon) and types of faults (e.g., read on hugetlbfs with a hole). The next commits will add different handling methods and more faults (e.g., uffd and dirty logging). This first commit starts by adding two sanity checks for all types of accesses: AF setting by the hw, and accessing memslots with holes. Signed-off-by: Ricardo Koller <ricarkol@google.com> --- tools/testing/selftests/kvm/.gitignore | 1 + tools/testing/selftests/kvm/Makefile | 1 + .../selftests/kvm/aarch64/page_fault_test.c | 595 ++++++++++++++++++ .../selftests/kvm/include/aarch64/processor.h | 8 + 4 files changed, 605 insertions(+) create mode 100644 tools/testing/selftests/kvm/aarch64/page_fault_test.c