[RFC PATCH v3 30/31] KVM: selftests: TDX: Add TDX UPM selftest

Ackerley Tng
2023-01-21T00:20:32Z

This tests the use of restricted memory with explicit MapGPA calls.

Signed-off-by: Ackerley Tng <ackerleytng@google.com>
---
tools/testing/selftests/kvm/.gitignore | 1 +
tools/testing/selftests/kvm/Makefile | 1 +
.../selftests/kvm/x86_64/tdx_upm_test.c | 392 ++++++++++++++++++
3 files changed, 394 insertions(+)
create mode 100644 tools/testing/selftests/kvm/x86_64/tdx_upm_test.c

diff --git a/tools/testing/selftests/kvm/.gitignore b/tools/testing/selftests/kvm/.gitignore
index e1663b0f809b4..c1def2271f4cd 100644
--- a/tools/testing/selftests/kvm/.gitignore
+++ b/tools/testing/selftests/kvm/.gitignore
@@ -67,6 +67,7 @@
/x86_64/triple_fault_event_test
/x86_64/tdx_vm_tests
/x86_64/tdx_shared_mem_test
+/x86_64/tdx_upm_test
/access_tracking_perf_test
/demand_paging_test
/dirty_log_test
diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
index 27e9148212fa5..2b1434368a0f2 100644
--- a/tools/testing/selftests/kvm/Makefile
+++ b/tools/testing/selftests/kvm/Makefile
@@ -153,6 +153,7 @@ TEST_GEN_PROGS_x86_64 += kvm_binary_stats_test
TEST_GEN_PROGS_x86_64 += system_counter_offset_test
TEST_GEN_PROGS_x86_64 += x86_64/tdx_vm_tests
TEST_GEN_PROGS_x86_64 += x86_64/tdx_shared_mem_test
+TEST_GEN_PROGS_x86_64 += x86_64/tdx_upm_test

# Compiled outputs used by test targets
TEST_GEN_PROGS_EXTENDED_x86_64 += x86_64/nx_huge_pages_test
diff --git a/tools/testing/selftests/kvm/x86_64/tdx_upm_test.c b/tools/testing/selftests/kvm/x86_64/tdx_upm_test.c
new file mode 100644
index 0000000000000..13914aebd7da7
--- /dev/null
+++ b/tools/testing/selftests/kvm/x86_64/tdx_upm_test.c
@@ -0,0 +1,392 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <asm/kvm.h>
+#include <asm/vmx.h>
+#include <linux/kvm.h>
+#include <stdbool.h>
+#include <stdint.h>
+
+#include "kvm_util_base.h"
+#include "processor.h"
+#include "tdx/tdcall.h"
+#include "tdx/tdx.h"
+#include "tdx/tdx_util.h"
+#include "tdx/test_util.h"
+#include "test_util.h"
+
+/* TDX UPM test patterns */
+#define PATTERN_CONFIDENCE_CHECK (0x11)
+#define PATTERN_HOST_FOCUS (0x22)
+#define PATTERN_GUEST_GENERAL (0x33)
+#define PATTERN_GUEST_FOCUS (0x44)
+
+/*
+ * 0x80000000 is arbitrarily selected. The selected address need not be the same
+ * as TDX_UPM_TEST_AREA_GVA_PRIVATE, but it should not overlap with selftest
+ * code or boot page.
+ */
+#define TDX_UPM_TEST_AREA_GPA (0x80000000)
+/* Test area GPA is arbitrarily selected */
+#define TDX_UPM_TEST_AREA_GVA_PRIVATE (0x90000000)
+/* Select any bit that can be used as a flag */
+#define TDX_UPM_TEST_AREA_GVA_SHARED_BIT (32)
+/*
+ * TDX_UPM_TEST_AREA_GVA_SHARED is used to map the same GPA twice into the
+ * guest, once as shared and once as private
+ */
+#define TDX_UPM_TEST_AREA_GVA_SHARED \
+ (TDX_UPM_TEST_AREA_GVA_PRIVATE | \
+ BIT_ULL(TDX_UPM_TEST_AREA_GVA_SHARED_BIT))
+
+/* The test area is 2MB in size */
+#define TDX_UPM_TEST_AREA_SIZE (2 << 20)
+/* 0th general area is 1MB in size */
+#define TDX_UPM_GENERAL_AREA_0_SIZE (1 << 20)
+/* Focus area is 40KB in size */
+#define TDX_UPM_FOCUS_AREA_SIZE (40 << 10)
+/* 1st general area is the rest of the space in the test area */
+#define TDX_UPM_GENERAL_AREA_1_SIZE \
+ (TDX_UPM_TEST_AREA_SIZE - TDX_UPM_GENERAL_AREA_0_SIZE - \
+ TDX_UPM_FOCUS_AREA_SIZE)
+
+/*
+ * The test memory area is set up as two general areas, sandwiching a focus
+ * area. The general areas act as control areas. After they are filled, they
+ * are not expected to change throughout the tests. The focus area is memory
+ * permissions change from private to shared and vice-versa.
+ *
+ * The focus area is intentionally small, and sandwiched to test that when the
+ * focus area's permissions change, the other areas' permissions are not
+ * affected.
+ */
+struct __packed tdx_upm_test_area {
+ uint8_t general_area_0[TDX_UPM_GENERAL_AREA_0_SIZE];
+ uint8_t focus_area[TDX_UPM_FOCUS_AREA_SIZE];
+ uint8_t general_area_1[TDX_UPM_GENERAL_AREA_1_SIZE];
+};
+
+static void fill_test_area(struct tdx_upm_test_area *test_area_base,
+ uint8_t pattern)
+{
+ memset(test_area_base, pattern, sizeof(*test_area_base));
+}
+
+static void fill_focus_area(struct tdx_upm_test_area *test_area_base,
+ uint8_t pattern)
+{
+ memset(test_area_base->focus_area, pattern,
+ sizeof(test_area_base->focus_area));
+}
+
+static bool check_area(uint8_t *base, uint64_t size, uint8_t expected_pattern)
+{
+ size_t i;
+
+ for (i = 0; i < size; i++) {
+ if (base[i] != expected_pattern)
+ return false;
+ }
+
+ return true;
+}
+
+static bool check_general_areas(struct tdx_upm_test_area *test_area_base,
+ uint8_t expected_pattern)
+{
+ return (check_area(test_area_base->general_area_0,
+ sizeof(test_area_base->general_area_0),
+ expected_pattern) &&
+ check_area(test_area_base->general_area_1,
+ sizeof(test_area_base->general_area_1),
+ expected_pattern));
+}
+
+static bool check_focus_area(struct tdx_upm_test_area *test_area_base,
+ uint8_t expected_pattern)
+{
+ return check_area(test_area_base->focus_area,
+ sizeof(test_area_base->focus_area), expected_pattern);
+}
+
+static bool check_test_area(struct tdx_upm_test_area *test_area_base,
+ uint8_t expected_pattern)
+{
+ return (check_general_areas(test_area_base, expected_pattern) &&
+ check_focus_area(test_area_base, expected_pattern));
+}
+
+static bool fill_and_check(struct tdx_upm_test_area *test_area_base, uint8_t pattern)
+{
+ fill_test_area(test_area_base, pattern);
+
+ return check_test_area(test_area_base, pattern);
+}
+
+#define TDX_UPM_TEST_ASSERT(x) \
+ do { \
+ if (!(x)) \
+ tdx_test_fatal(__LINE__); \
+ } while (0)
+
+/*
+ * Shared variables between guest and host
+ */
+static struct tdx_upm_test_area *test_area_gpa_private;
+static struct tdx_upm_test_area *test_area_gpa_shared;
+
+/*
+ * Test stages for syncing with host
+ */
+enum {
+ SYNC_CHECK_READ_PRIVATE_MEMORY_FROM_HOST = 1,
+ SYNC_CHECK_READ_SHARED_MEMORY_FROM_HOST,
+ SYNC_CHECK_READ_PRIVATE_MEMORY_FROM_HOST_AGAIN,
+};
+
+#define TDX_UPM_TEST_ACCEPT_PRINT_PORT 0x87
+
+/**
+ * Does vcpu_run, and also manages memory conversions if requested by the TD.
+ */
+void vcpu_run_and_manage_memory_conversions(struct kvm_vm *vm,
+ struct kvm_vcpu *vcpu)
+{
+ for (;;) {
+ vcpu_run(vcpu);
+ if (
+ vcpu->run->exit_reason == KVM_EXIT_IO &&
+ vcpu->run->io.port == TDX_UPM_TEST_ACCEPT_PRINT_PORT) {
+ uint64_t gpa = tdx_test_read_64bit(
+ vcpu, TDX_UPM_TEST_ACCEPT_PRINT_PORT);
+ printf("\t ... guest accepting 1 page at GPA: 0x%lx\n", gpa);
+ continue;
+ }
+
+ break;
+ }
+}
+
+static void guest_upm_explicit(void)
+{
+ uint64_t ret = 0;
+ uint64_t failed_gpa;
+
+ struct tdx_upm_test_area *test_area_gva_private =
+ (struct tdx_upm_test_area *)TDX_UPM_TEST_AREA_GVA_PRIVATE;
+ struct tdx_upm_test_area *test_area_gva_shared =
+ (struct tdx_upm_test_area *)TDX_UPM_TEST_AREA_GVA_SHARED;
+
+ /* Check: host reading private memory does not modify guest's view */
+ fill_test_area(test_area_gva_private, PATTERN_GUEST_GENERAL);
+
+ tdx_test_report_to_user_space(SYNC_CHECK_READ_PRIVATE_MEMORY_FROM_HOST);
+
+ TDX_UPM_TEST_ASSERT(
+ check_test_area(test_area_gva_private, PATTERN_GUEST_GENERAL));
+
+ /* Remap focus area as shared */
+ ret = tdg_vp_vmcall_map_gpa((uint64_t)test_area_gpa_shared->focus_area,
+ sizeof(test_area_gpa_shared->focus_area),
+ &failed_gpa);
+ TDX_UPM_TEST_ASSERT(!ret);
+
+ /* General areas should be unaffected by remapping */
+ TDX_UPM_TEST_ASSERT(
+ check_general_areas(test_area_gva_private, PATTERN_GUEST_GENERAL));
+
+ /*
+ * Use memory contents to confirm that the memory allocated using mmap
+ * is used as backing memory for shared memory - PATTERN_CONFIDENCE_CHECK
+ * was written by the VMM at the beginning of this test.
+ */
+ TDX_UPM_TEST_ASSERT(
+ check_focus_area(test_area_gva_shared, PATTERN_CONFIDENCE_CHECK));
+
+ /* Guest can use focus area after remapping as shared */
+ fill_focus_area(test_area_gva_shared, PATTERN_GUEST_FOCUS);
+
+ tdx_test_report_to_user_space(SYNC_CHECK_READ_SHARED_MEMORY_FROM_HOST);
+
+ /* Check that guest has the same view of shared memory */
+ TDX_UPM_TEST_ASSERT(
+ check_focus_area(test_area_gva_shared, PATTERN_HOST_FOCUS));
+
+ /* Remap focus area back to private */
+ ret = tdg_vp_vmcall_map_gpa((uint64_t)test_area_gpa_private->focus_area,
+ sizeof(test_area_gpa_private->focus_area),
+ &failed_gpa);
+ TDX_UPM_TEST_ASSERT(!ret);
+
+ /* General areas should be unaffected by remapping */
+ TDX_UPM_TEST_ASSERT(
+ check_general_areas(test_area_gva_private, PATTERN_GUEST_GENERAL));
+
+ /* Focus area should be zeroed after remapping */
+ TDX_UPM_TEST_ASSERT(check_focus_area(test_area_gva_private, 0));
+
+ tdx_test_report_to_user_space(SYNC_CHECK_READ_PRIVATE_MEMORY_FROM_HOST_AGAIN);
+
+ /* Check that guest can use private memory after focus area is remapped as private */
+ TDX_UPM_TEST_ASSERT(
+ fill_and_check(test_area_gva_private, PATTERN_GUEST_GENERAL));
+
+ tdx_test_success();
+}
+
+static void run_selftest(struct kvm_vm *vm, struct kvm_vcpu *vcpu,
+ struct tdx_upm_test_area *test_area_base_hva)
+{
+ vcpu_run(vcpu);
+ TDX_TEST_CHECK_GUEST_FAILURE(vcpu);
+ TDX_TEST_ASSERT_IO(vcpu, TDX_TEST_REPORT_PORT, TDX_TEST_REPORT_SIZE,
+ TDG_VP_VMCALL_INSTRUCTION_IO_WRITE);
+ ASSERT_EQ(*(uint32_t *)((void *)vcpu->run + vcpu->run->io.data_offset),
+ SYNC_CHECK_READ_PRIVATE_MEMORY_FROM_HOST);
+
+ /*
+ * Check that host should read PATTERN_CONFIDENCE_CHECK from guest's
+ * private memory. This confirms that regular memory (userspace_addr in
+ * struct kvm_userspace_memory_region) is used to back the host's view
+ * of private memory, since PATTERN_CONFIDENCE_CHECK was written to that
+ * memory before starting the guest.
+ */
+ TEST_ASSERT(check_test_area(test_area_base_hva, PATTERN_CONFIDENCE_CHECK),
+ "Host should read PATTERN_CONFIDENCE_CHECK from guest's private memory.");
+
+ vcpu_run_and_manage_memory_conversions(vm, vcpu);
+ TDX_TEST_CHECK_GUEST_FAILURE(vcpu);
+ TDX_TEST_ASSERT_IO(vcpu, TDX_TEST_REPORT_PORT, TDX_TEST_REPORT_SIZE,
+ TDG_VP_VMCALL_INSTRUCTION_IO_WRITE);
+ ASSERT_EQ(*(uint32_t *)((void *)vcpu->run + vcpu->run->io.data_offset),
+ SYNC_CHECK_READ_SHARED_MEMORY_FROM_HOST);
+
+ TEST_ASSERT(check_focus_area(test_area_base_hva, PATTERN_GUEST_FOCUS),
+ "Host should have the same view of shared memory as guest.");
+ TEST_ASSERT(check_general_areas(test_area_base_hva, PATTERN_CONFIDENCE_CHECK),
+ "Host's view of private memory should still be backed by regular memory.");
+
+ /* Check that host can use shared memory */
+ fill_focus_area(test_area_base_hva, PATTERN_HOST_FOCUS);
+ TEST_ASSERT(check_focus_area(test_area_base_hva, PATTERN_HOST_FOCUS),
+ "Host should be able to use shared memory.");
+
+ vcpu_run_and_manage_memory_conversions(vm, vcpu);
+ TDX_TEST_CHECK_GUEST_FAILURE(vcpu);
+ TDX_TEST_ASSERT_IO(vcpu, TDX_TEST_REPORT_PORT, TDX_TEST_REPORT_SIZE,
+ TDG_VP_VMCALL_INSTRUCTION_IO_WRITE);
+ ASSERT_EQ(*(uint32_t *)((void *)vcpu->run + vcpu->run->io.data_offset),
+ SYNC_CHECK_READ_PRIVATE_MEMORY_FROM_HOST_AGAIN);
+
+ TEST_ASSERT(check_general_areas(test_area_base_hva, PATTERN_CONFIDENCE_CHECK),
+ "Host's view of private memory should be backed by regular memory.");
+ TEST_ASSERT(check_focus_area(test_area_base_hva, PATTERN_HOST_FOCUS),
+ "Host's view of private memory should be backed by regular memory.");
+
+ vcpu_run(vcpu);
+ TDX_TEST_CHECK_GUEST_FAILURE(vcpu);
+ TDX_TEST_ASSERT_SUCCESS(vcpu);
+
+ printf("\t ... PASSED\n");
+}
+
+static bool address_between(uint64_t addr, void *lo, void *hi)
+{
+ return (uint64_t)lo <= addr && addr < (uint64_t)hi;
+}
+
+static void guest_ve_handler(struct ex_regs *regs)
+{
+ uint64_t ret;
+ struct ve_info ve;
+
+ ret = tdg_vp_veinfo_get(&ve);
+ TDX_UPM_TEST_ASSERT(!ret);
+
+ /* For this test, we will only handle EXIT_REASON_EPT_VIOLATION */
+ TDX_UPM_TEST_ASSERT(ve.exit_reason == EXIT_REASON_EPT_VIOLATION);
+
+ /* Validate GPA in fault */
+ TDX_UPM_TEST_ASSERT(
+ address_between(ve.gpa,
+ test_area_gpa_private->focus_area,
+ test_area_gpa_private->general_area_1));
+
+ tdx_test_send_64bit(TDX_UPM_TEST_ACCEPT_PRINT_PORT, ve.gpa);
+
+#define MEM_PAGE_ACCEPT_LEVEL_4K 0
+#define MEM_PAGE_ACCEPT_LEVEL_2M 1
+ ret = tdg_mem_page_accept(ve.gpa, MEM_PAGE_ACCEPT_LEVEL_4K);
+ TDX_UPM_TEST_ASSERT(!ret);
+}
+
+static void verify_upm_test(void)
+{
+ struct kvm_vm *vm;
+ struct kvm_vcpu *vcpu;
+
+ vm_vaddr_t test_area_gva_private;
+ struct tdx_upm_test_area *test_area_base_hva;
+ uint64_t test_area_npages;
+
+ vm = td_create();
+ td_initialize(vm, VM_MEM_SRC_ANONYMOUS, 0);
+ vcpu = td_vcpu_add(vm, 0, guest_upm_explicit);
+
+ vm_install_exception_handler(vm, VE_VECTOR, guest_ve_handler);
+
+ /*
+ * Set up shared memory page for testing by first allocating as private
+ * and then mapping the same GPA again as shared. This way, the TD does
+ * not have to remap its page tables at runtime.
+ */
+ test_area_npages = TDX_UPM_TEST_AREA_SIZE / vm->page_size;
+ vm_userspace_mem_region_add(vm,
+ VM_MEM_SRC_ANONYMOUS_AND_RESTRICTED_MEMFD,
+ TDX_UPM_TEST_AREA_GPA, 3, test_area_npages,
+ 0);
+
+ test_area_gva_private = _vm_vaddr_alloc(
+ vm, TDX_UPM_TEST_AREA_SIZE, TDX_UPM_TEST_AREA_GVA_PRIVATE,
+ TDX_UPM_TEST_AREA_GPA, 3, true);
+ ASSERT_EQ(test_area_gva_private, TDX_UPM_TEST_AREA_GVA_PRIVATE);
+
+ test_area_gpa_private = (struct tdx_upm_test_area *)
+ addr_gva2gpa(vm, test_area_gva_private);
+ virt_map_shared(vm, TDX_UPM_TEST_AREA_GVA_SHARED,
+ (uint64_t)test_area_gpa_private,
+ test_area_npages);
+ ASSERT_EQ(addr_gva2gpa(vm, TDX_UPM_TEST_AREA_GVA_SHARED),
+ (vm_paddr_t)test_area_gpa_private);
+
+ test_area_base_hva = addr_gva2hva(vm, TDX_UPM_TEST_AREA_GVA_PRIVATE);
+
+ TEST_ASSERT(fill_and_check(test_area_base_hva, PATTERN_CONFIDENCE_CHECK),
+ "Failed to mark memory intended as backing memory for TD shared memory");
+
+ sync_global_to_guest(vm, test_area_gpa_private);
+ test_area_gpa_shared = (struct tdx_upm_test_area *)
+ ((uint64_t)test_area_gpa_private | BIT_ULL(vm->pa_bits - 1));
+ sync_global_to_guest(vm, test_area_gpa_shared);
+
+ td_finalize(vm);
+
+ printf("Verifying UPM functionality: explicit MapGPA\n");
+
+ run_selftest(vm, vcpu, test_area_base_hva);
+
+ kvm_vm_free(vm);
+}
+
+int main(int argc, char **argv)
+{
+ /* Disable stdout buffering */
+ setbuf(stdout, NULL);
+
+ if (!is_tdx_enabled()) {
+ printf("TDX is not supported by the KVM\n"
+ "Skipping the TDX tests.\n");
+ return 0;
+ }
+
+ run_in_new_process(&verify_upm_test);
+}
--
2.39.0.246.g2a6d74b583-goog