[RFC PATCH v2 6/6] KVM: guest_memfd: selftest: Add test case for error_remove_page method

isaku.yamahata
2023-09-21T20:42:05Z

From: Isaku Yamahata <isaku.yamahata@intel.com>

This test case implements fault injection into guest memory by
madvise(MADV_HWPOISON) for shared(conventional) memory region and
KVM_GUEST_MEMORY_FAILURE for private gmem region. Once page is poisoned,
free the poisoned page and try to run vcpu again to see a new zero page is
assigned.

Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
---
tools/testing/selftests/kvm/Makefile | 1 +
.../kvm/x86_64/private_mem_hwpoison_test.c | 367 ++++++++++++++++++
2 files changed, 368 insertions(+)
create mode 100644 tools/testing/selftests/kvm/x86_64/private_mem_hwpoison_test.c

diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
index f7fdd8244547..a72d0946c233 100644
--- a/tools/testing/selftests/kvm/Makefile
+++ b/tools/testing/selftests/kvm/Makefile
@@ -82,6 +82,7 @@ TEST_GEN_PROGS_x86_64 += x86_64/nested_exceptions_test
TEST_GEN_PROGS_x86_64 += x86_64/platform_info_test
TEST_GEN_PROGS_x86_64 += x86_64/pmu_event_filter_test
TEST_GEN_PROGS_x86_64 += x86_64/private_mem_conversions_test
+TEST_GEN_PROGS_x86_64 += x86_64/private_mem_hwpoison_test
TEST_GEN_PROGS_x86_64 += x86_64/private_mem_kvm_exits_test
TEST_GEN_PROGS_x86_64 += x86_64/set_boot_cpu_id
TEST_GEN_PROGS_x86_64 += x86_64/set_sregs_test
diff --git a/tools/testing/selftests/kvm/x86_64/private_mem_hwpoison_test.c b/tools/testing/selftests/kvm/x86_64/private_mem_hwpoison_test.c
new file mode 100644
index 000000000000..78242ee8c8db
--- /dev/null
+++ b/tools/testing/selftests/kvm/x86_64/private_mem_hwpoison_test.c
@@ -0,0 +1,367 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2022, Google LLC.
+ * Copyright (C) 2023, Intel Corp.
+ */
+#define _GNU_SOURCE /* for program_invocation_short_name */
+#include <fcntl.h>
+#include <limits.h>
+#include <pthread.h>
+#include <sched.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/ioctl.h>
+#include <setjmp.h>
+
+#include <linux/compiler.h>
+#include <linux/kernel.h>
+#include <linux/kvm_para.h>
+#include <linux/memfd.h>
+#include <linux/sizes.h>
+#include <linux/fs.h>
+
+#include <test_util.h>
+#include <kvm_util.h>
+#include <processor.h>
+
+#define BASE_DATA_SLOT 10
+#define BASE_DATA_GPA ((uint64_t)(1ull << 32))
+#define PER_CPU_DATA_SIZE ((uint64_t)(SZ_2M))
+
+enum ucall_syncs {
+ HWPOISON_SHARED,
+ HWPOISON_PRIVATE,
+};
+
+static void guest_sync_shared(uint64_t gpa)
+{
+ GUEST_SYNC2(HWPOISON_SHARED, gpa);
+}
+
+static void guest_sync_private(uint64_t gpa)
+{
+ GUEST_SYNC2(HWPOISON_PRIVATE, gpa);
+}
+
+/* Arbitrary values, KVM doesn't care about the attribute flags. */
+#define MAP_GPA_SHARED BIT(0)
+#define MAP_GPA_DO_FALLOCATE BIT(1)
+#define MAP_GPA_HWPOISON BIT(2)
+
+static void guest_map_mem(uint64_t gpa, uint64_t size, bool map_shared,
+ bool do_fallocate, bool hwpoison)
+{
+ uint64_t flags = 0;
+
+ if (map_shared)
+ flags |= MAP_GPA_SHARED;
+ if (do_fallocate)
+ flags |= MAP_GPA_DO_FALLOCATE;
+ if (hwpoison)
+ flags |= MAP_GPA_HWPOISON;
+ kvm_hypercall_map_gpa_range(gpa, size, flags);
+}
+
+static void guest_map_shared(uint64_t gpa, uint64_t size, bool do_fallocate,
+ bool hwpoison)
+{
+ guest_map_mem(gpa, size, true, do_fallocate, hwpoison);
+}
+
+static void guest_map_private(uint64_t gpa, uint64_t size, bool do_fallocate,
+ bool hwpoison)
+{
+ guest_map_mem(gpa, size, false, do_fallocate, hwpoison);
+}
+
+static void guest_run_test(uint64_t base_gpa, bool huge_page,
+ bool test_shared)
+{
+ uint64_t gpa = base_gpa + (huge_page ? 0 : PAGE_SIZE);
+ uint64_t size = huge_page ? SZ_2M : PAGE_SIZE;
+ const uint8_t init_p = 0xcc;
+ uint64_t r;
+
+ /* Memory should be shared by default. */
+ guest_map_shared(base_gpa, PER_CPU_DATA_SIZE, true, false);
+ memset((void *)base_gpa, 0, PER_CPU_DATA_SIZE);
+
+ /*
+ * Set the test region to non-zero to differentiate it from the page
+ * newly assigned.
+ */
+ memset((void *)gpa, init_p, size);
+
+ /* Ask VMM to convert to private/shared the page and poison it. */
+ if (test_shared) {
+ guest_map_shared(gpa, size, true, true);
+ guest_sync_shared(gpa);
+ } else {
+ guest_map_private(gpa, size, true, true);
+ guest_sync_private(gpa);
+ }
+
+ /* Consume poisoned data. */
+ r = READ_ONCE(*(uint64_t *)gpa);
+ /* Discard the poisoned page and assign a new page. */
+ GUEST_ASSERT_EQ((uint8_t)r, 0);
+}
+
+static void guest_code(uint64_t base_gpa, bool huge_page, bool test_shared)
+{
+ guest_run_test(base_gpa, huge_page, test_shared);
+ GUEST_DONE();
+}
+
+static void handle_exit_hypercall(struct kvm_vcpu *vcpu)
+{
+ struct kvm_run *run = vcpu->run;
+ uint64_t gpa = run->hypercall.args[0];
+ uint64_t size = run->hypercall.args[1] * PAGE_SIZE;
+ bool map_shared = run->hypercall.args[2] & MAP_GPA_SHARED;
+ bool do_fallocate = run->hypercall.args[2] & MAP_GPA_DO_FALLOCATE;
+ struct kvm_vm *vm = vcpu->vm;
+
+ TEST_ASSERT(run->hypercall.nr == KVM_HC_MAP_GPA_RANGE,
+ "Wanted MAP_GPA_RANGE (%u), got '%llu'",
+ KVM_HC_MAP_GPA_RANGE, run->hypercall.nr);
+
+ if (do_fallocate)
+ vm_guest_mem_fallocate(vm, gpa, size, map_shared);
+
+ vm_set_memory_attributes(vm, gpa, size,
+ map_shared ? 0 : KVM_MEMORY_ATTRIBUTE_PRIVATE);
+ run->hypercall.ret = 0;
+}
+
+static void inject_memory_failure(int gmem_fd, uint64_t gpa)
+{
+ /* See vm_mem_add() in test_mem_failure() */
+ uint64_t offset = gpa - BASE_DATA_GPA;
+ struct kvm_guest_memory_failure mf = {
+ .offset = offset,
+ };
+ int ret;
+
+ ret = ioctl(gmem_fd, KVM_GUEST_MEMORY_FAILURE, &mf);
+ __TEST_REQUIRE(!(ret == -1 && errno == EPERM),
+ "Injecting memory fault requires CAP_SYS_ADMIN");
+ TEST_ASSERT(!ret || (ret == -1 && errno == EBUSY),
+ "ioctl(KVM_GUEST_MEMORY_FAILURE) should success");
+}
+
+static sigjmp_buf sigbuf;
+
+static void sigbus_handler(int sig, siginfo_t *info, void *data)
+{
+ TEST_ASSERT(sig == SIGBUS, "Unknown signal received %d\n", sig);
+ siglongjmp(sigbuf, 1);
+}
+
+static bool run_vcpus;
+
+struct test_args {
+ struct kvm_vcpu *vcpu;
+ int gmem_fd;
+ bool huge_page;
+ bool test_shared;
+};
+
+static void *__test_mem_failure(void *__args)
+{
+ struct test_args *args = __args;
+ struct kvm_vcpu *vcpu = args->vcpu;
+ struct kvm_run *run = vcpu->run;
+ struct kvm_vm *vm = vcpu->vm;
+ int gmem_fd = args->gmem_fd;
+ struct ucall uc;
+
+ while (!READ_ONCE(run_vcpus))
+ ;
+
+ for ( ;; ) {
+ vcpu_run(vcpu);
+
+ if (run->exit_reason == KVM_EXIT_HYPERCALL) {
+ handle_exit_hypercall(vcpu);
+ continue;
+ }
+
+ TEST_ASSERT(run->exit_reason == KVM_EXIT_IO,
+ "Wanted KVM_EXIT_IO, got exit reason: %u (%s)",
+ run->exit_reason, exit_reason_str(run->exit_reason));
+
+ switch (get_ucall(vcpu, &uc)) {
+ case UCALL_ABORT:
+ REPORT_GUEST_ASSERT(uc);
+ break;
+ case UCALL_SYNC: {
+ uint64_t gpa = uc.args[1];
+
+ TEST_ASSERT(uc.args[0] == HWPOISON_SHARED ||
+ uc.args[0] == HWPOISON_PRIVATE,
+ "Unknown sync command '%ld'", uc.args[0]);
+
+ if (uc.args[0] == HWPOISON_PRIVATE) {
+ int ret;
+
+ inject_memory_failure(gmem_fd, gpa);
+ ret = _vcpu_run(vcpu);
+ TEST_ASSERT(ret == -1 && errno == EHWPOISON &&
+ run->exit_reason == KVM_EXIT_MEMORY_FAULT,
+ "exit_reason 0x%x",
+ run->exit_reason);
+ /* Discard the poisoned page and assign new page. */
+ vm_guest_mem_fallocate(vm, gpa, PAGE_SIZE, true);
+ } else {
+ uint8_t *hva = addr_gpa2hva(vm, gpa);
+ int r;
+
+ r = madvise(hva, 8, MADV_HWPOISON);
+ __TEST_REQUIRE(!(r == -1 && errno == EPERM),
+ "madvise(MADV_HWPOISON) requires CAP_SYS_ADMIN");
+ TEST_ASSERT(!r, "madvise(MADV_HWPOISON) should succeed");
+ if (sigsetjmp(sigbuf, 1)) {
+ TEST_ASSERT(!sigaction(SIGBUS, NULL, NULL),
+ "sigaction should success");
+ r = madvise(hva, PAGE_SIZE, MADV_FREE);
+ TEST_ASSERT(!r, "madvise(MADV_FREE) should success");
+ } else {
+ struct sigaction sa = {
+ .sa_sigaction = sigbus_handler,
+ .sa_flags = SA_SIGINFO,
+ };
+ TEST_ASSERT(!sigaction(SIGBUS, &sa, NULL),
+ "sigaction should success");
+ /* Trigger SIGBUS */
+ vcpu_run(vcpu);
+ }
+ }
+ break;
+ }
+ case UCALL_DONE:
+ return NULL;
+ default:
+ TEST_FAIL("Unknown ucall 0x%lx.", uc.cmd);
+ }
+ }
+}
+
+static void test_mem_failure(enum vm_mem_backing_src_type src_type, uint32_t nr_vcpus,
+ uint32_t nr_memslots, bool huge_page, bool test_shared)
+{
+ /*
+ * Allocate enough memory so that each vCPU's chunk of memory can be
+ * naturally aligned with respect to the size of the backing store.
+ */
+ const size_t size = align_up(PER_CPU_DATA_SIZE, get_backing_src_pagesz(src_type));
+ const size_t memfd_size = size * nr_vcpus;
+ struct kvm_vcpu *vcpus[KVM_MAX_VCPUS];
+ pthread_t threads[KVM_MAX_VCPUS];
+ uint64_t gmem_flags;
+ struct kvm_vm *vm;
+ int memfd, i;
+
+ const struct vm_shape shape = {
+ .mode = VM_MODE_DEFAULT,
+ .type = KVM_X86_SW_PROTECTED_VM,
+ };
+
+ vm = __vm_create_with_vcpus(shape, nr_vcpus, 0, guest_code, vcpus);
+
+ vm_enable_cap(vm, KVM_CAP_EXIT_HYPERCALL, (1 << KVM_HC_MAP_GPA_RANGE));
+
+ if (huge_page && !backing_src_can_be_huge(src_type))
+ TEST_FAIL("Huge page is requested, but not supported");
+ if (backing_src_can_be_huge(src_type))
+ gmem_flags = KVM_GUEST_MEMFD_ALLOW_HUGEPAGE;
+ else
+ gmem_flags = 0;
+ memfd = vm_create_guest_memfd(vm, memfd_size, gmem_flags);
+
+ for (i = 0; i < nr_memslots; i++)
+ vm_mem_add(vm, src_type, BASE_DATA_GPA + size * i,
+ BASE_DATA_SLOT + i, size / vm->page_size,
+ KVM_MEM_PRIVATE, memfd, size * i);
+
+ for (i = 0; i < nr_vcpus; i++) {
+ uint64_t gpa = BASE_DATA_GPA + i * size;
+ struct test_args args;
+
+ vcpu_args_set(vcpus[i], 3, gpa, huge_page, test_shared);
+
+ virt_map(vm, gpa, gpa, size / vm->page_size);
+
+ args = (struct test_args) {
+ .vcpu = vcpus[i],
+ .gmem_fd = memfd,
+ .huge_page = huge_page,
+ .test_shared = test_shared,
+ };
+ pthread_create(&threads[i], NULL, __test_mem_failure, &args);
+ }
+
+ WRITE_ONCE(run_vcpus, true);
+
+ for (i = 0; i < nr_vcpus; i++)
+ pthread_join(threads[i], NULL);
+
+ kvm_vm_free(vm);
+
+ close(memfd);
+}
+
+static void help(const char *prog_name)
+{
+ printf("usage: %s [-h] [-m] [-M] [-n nr_vcpus] [-s mem_type] [-?]\n"
+ " -h: use huge page\n"
+ " -m: use multiple memslots (default: 1)\n"
+ " -n: specify the number of vcpus (default: 1)\n"
+ " -s: specify the memory type\n"
+ " -?: print this message\n",
+ prog_name);
+}
+
+int main(int argc, char *argv[])
+{
+ enum vm_mem_backing_src_type src_type = DEFAULT_VM_MEM_SRC;
+ bool use_multiple_memslots = false;
+ bool huge_page = false;
+ uint32_t nr_vcpus = 1;
+ uint32_t nr_memslots;
+ int opt;
+
+ TEST_REQUIRE(kvm_has_cap(KVM_CAP_EXIT_HYPERCALL));
+ TEST_REQUIRE(kvm_check_cap(KVM_CAP_VM_TYPES) &
+ BIT(KVM_X86_SW_PROTECTED_VM));
+
+ while ((opt = getopt(argc, argv, "hmn:s:S?")) != -1) {
+ switch (opt) {
+ case 'h':
+ huge_page = true;
+ break;
+ case 'm':
+ use_multiple_memslots = true;
+ break;
+ case 'n':
+ nr_vcpus = atoi_positive("nr_vcpus", optarg);
+ break;
+ case 's':
+ src_type = parse_backing_src_type(optarg);
+ break;
+ case '?':
+ default:
+ help(argv[0]);
+ exit(0);
+ }
+ }
+
+ nr_memslots = use_multiple_memslots ? nr_vcpus : 1;
+
+ test_mem_failure(src_type, nr_vcpus, nr_memslots, huge_page, true);
+ test_mem_failure(src_type, nr_vcpus, nr_memslots, huge_page, false);
+
+ return 0;
+}
--
2.25.1