[RFC PATCH v3 09/31] KVM: selftests: TDX: Add TDX lifecycle test

Ackerley Tng
2023-01-21T00:17:38Z

From: Erdem Aktas <erdemaktas@google.com>

Adding a test to verify TDX lifecycle by creating a TD and running a
dummy TDG.VP.VMCALL <Instruction.IO> inside it.

Signed-off-by: Erdem Aktas <erdemaktas@google.com>
Signed-off-by: Ryan Afranji <afranji@google.com>
Signed-off-by: Sagi Shahar <sagis@google.com>
Co-developed-by: Ackerley Tng <ackerleytng@google.com>
Signed-off-by: Ackerley Tng <ackerleytng@google.com>
---
Changes RFCv2 -> RFCv3
+ Add gitignore for tdx_vm_tests binary
+ Thanks to Isaku for the comment about saving rbp separately for gcc!
In this revision, the assembly that wraps tdcall has been mostly taken
from the kernel’s implementation, which would be familiar to you!
+ TDX test-related code is now grouped in
tools/testing/selftests/kvm/include/x86_64/tdx/test_util.{c,h} and
test-related functions and macros are prefixed with tdx_test to
indicate its purpose.
---
tools/testing/selftests/kvm/.gitignore | 1 +
tools/testing/selftests/kvm/Makefile | 4 +
.../selftests/kvm/include/x86_64/tdx/tdcall.h | 35 ++++++++
.../selftests/kvm/include/x86_64/tdx/tdx.h | 12 +++
.../kvm/include/x86_64/tdx/test_util.h | 52 +++++++++++
.../selftests/kvm/lib/x86_64/tdx/tdcall.S | 90 +++++++++++++++++++
.../selftests/kvm/lib/x86_64/tdx/tdx.c | 27 ++++++
.../selftests/kvm/lib/x86_64/tdx/test_util.c | 34 +++++++
.../selftests/kvm/x86_64/tdx_vm_tests.c | 45 ++++++++++
9 files changed, 300 insertions(+)
create mode 100644 tools/testing/selftests/kvm/include/x86_64/tdx/tdcall.h
create mode 100644 tools/testing/selftests/kvm/include/x86_64/tdx/tdx.h
create mode 100644 tools/testing/selftests/kvm/include/x86_64/tdx/test_util.h
create mode 100644 tools/testing/selftests/kvm/lib/x86_64/tdx/tdcall.S
create mode 100644 tools/testing/selftests/kvm/lib/x86_64/tdx/tdx.c
create mode 100644 tools/testing/selftests/kvm/lib/x86_64/tdx/test_util.c
create mode 100644 tools/testing/selftests/kvm/x86_64/tdx_vm_tests.c

diff --git a/tools/testing/selftests/kvm/.gitignore b/tools/testing/selftests/kvm/.gitignore
index 813e7610619d9..370d6430b32b4 100644
--- a/tools/testing/selftests/kvm/.gitignore
+++ b/tools/testing/selftests/kvm/.gitignore
@@ -65,6 +65,7 @@
/x86_64/xss_msr_test
/x86_64/vmx_pmu_caps_test
/x86_64/triple_fault_event_test
+/x86_64/tdx_vm_tests
/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 5f9cc1e6ee67e..9f289322a4933 100644
--- a/tools/testing/selftests/kvm/Makefile
+++ b/tools/testing/selftests/kvm/Makefile
@@ -61,6 +61,9 @@ LIBKVM_x86_64 += lib/x86_64/vmx.c
LIBKVM_x86_64 += lib/x86_64/sev.c
LIBKVM_x86_64 += lib/x86_64/tdx/tdx_util.c
LIBKVM_x86_64 += lib/x86_64/tdx/td_boot.S
+LIBKVM_x86_64 += lib/x86_64/tdx/tdcall.S
+LIBKVM_x86_64 += lib/x86_64/tdx/tdx.c
+LIBKVM_x86_64 += lib/x86_64/tdx/test_util.c

LIBKVM_aarch64 += lib/aarch64/gic.c
LIBKVM_aarch64 += lib/aarch64/gic_v3.c
@@ -148,6 +151,7 @@ TEST_GEN_PROGS_x86_64 += set_memory_region_test
TEST_GEN_PROGS_x86_64 += steal_time
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

# 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/include/x86_64/tdx/tdcall.h b/tools/testing/selftests/kvm/include/x86_64/tdx/tdcall.h
new file mode 100644
index 0000000000000..78001bfec9c8d
--- /dev/null
+++ b/tools/testing/selftests/kvm/include/x86_64/tdx/tdcall.h
@@ -0,0 +1,35 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/* Adapted from arch/x86/include/asm/shared/tdx.h */
+
+#ifndef SELFTESTS_TDX_TDCALL_H
+#define SELFTESTS_TDX_TDCALL_H
+
+#include <linux/bits.h>
+#include <linux/types.h>
+
+#define TDG_VP_VMCALL_INSTRUCTION_IO_READ 0
+#define TDG_VP_VMCALL_INSTRUCTION_IO_WRITE 1
+
+#define TDX_HCALL_HAS_OUTPUT BIT(0)
+
+#define TDX_HYPERCALL_STANDARD 0
+
+/*
+ * Used in __tdx_hypercall() to pass down and get back registers' values of
+ * the TDCALL instruction when requesting services from the VMM.
+ *
+ * This is a software only structure and not part of the TDX module/VMM ABI.
+ */
+struct tdx_hypercall_args {
+ u64 r10;
+ u64 r11;
+ u64 r12;
+ u64 r13;
+ u64 r14;
+ u64 r15;
+};
+
+/* Used to request services from the VMM */
+u64 __tdx_hypercall(struct tdx_hypercall_args *args, unsigned long flags);
+
+#endif // SELFTESTS_TDX_TDCALL_H
diff --git a/tools/testing/selftests/kvm/include/x86_64/tdx/tdx.h b/tools/testing/selftests/kvm/include/x86_64/tdx/tdx.h
new file mode 100644
index 0000000000000..a7161efe4ee2e
--- /dev/null
+++ b/tools/testing/selftests/kvm/include/x86_64/tdx/tdx.h
@@ -0,0 +1,12 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef SELFTEST_TDX_TDX_H
+#define SELFTEST_TDX_TDX_H
+
+#include <stdint.h>
+
+#define TDG_VP_VMCALL_INSTRUCTION_IO 30
+
+uint64_t tdg_vp_vmcall_instruction_io(uint64_t port, uint64_t size,
+ uint64_t write, uint64_t *data);
+
+#endif // SELFTEST_TDX_TDX_H
diff --git a/tools/testing/selftests/kvm/include/x86_64/tdx/test_util.h b/tools/testing/selftests/kvm/include/x86_64/tdx/test_util.h
new file mode 100644
index 0000000000000..b570b6d978ff1
--- /dev/null
+++ b/tools/testing/selftests/kvm/include/x86_64/tdx/test_util.h
@@ -0,0 +1,52 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef SELFTEST_TDX_TEST_UTIL_H
+#define SELFTEST_TDX_TEST_UTIL_H
+
+#include <stdbool.h>
+
+#include "tdcall.h"
+
+#define TDX_TEST_SUCCESS_PORT 0x30
+#define TDX_TEST_SUCCESS_SIZE 4
+
+/**
+ * Assert that tdx_test_success() was called in the guest.
+ */
+#define TDX_TEST_ASSERT_SUCCESS(VCPU) \
+ (TEST_ASSERT( \
+ ((VCPU)->run->exit_reason == KVM_EXIT_IO) && \
+ ((VCPU)->run->io.port == TDX_TEST_SUCCESS_PORT) && \
+ ((VCPU)->run->io.size == TDX_TEST_SUCCESS_SIZE) && \
+ ((VCPU)->run->io.direction == \
+ TDG_VP_VMCALL_INSTRUCTION_IO_WRITE), \
+ "Unexpected exit values while waiting for test completion: %u (%s) %d %d %d\n", \
+ (VCPU)->run->exit_reason, \
+ exit_reason_str((VCPU)->run->exit_reason), \
+ (VCPU)->run->io.port, (VCPU)->run->io.size, \
+ (VCPU)->run->io.direction))
+
+/**
+ * Run a test in a new process.
+ *
+ * There might be multiple tests we are running and if one test fails, it will
+ * prevent the subsequent tests to run due to how tests are failing with
+ * TEST_ASSERT function. The run_in_new_process function will run a test in a
+ * new process context and wait for it to finish or fail to prevent TEST_ASSERT
+ * to kill the main testing process.
+ */
+void run_in_new_process(void (*func)(void));
+
+/**
+ * Verify that the TDX is supported by KVM.
+ */
+bool is_tdx_enabled(void);
+
+/**
+ * Report test success to userspace.
+ *
+ * Use TDX_TEST_ASSERT_SUCCESS() to assert that this function was called in the
+ * guest.
+ */
+void tdx_test_success(void);
+
+#endif // SELFTEST_TDX_TEST_UTIL_H
diff --git a/tools/testing/selftests/kvm/lib/x86_64/tdx/tdcall.S b/tools/testing/selftests/kvm/lib/x86_64/tdx/tdcall.S
new file mode 100644
index 0000000000000..df9c1ed4bb2d1
--- /dev/null
+++ b/tools/testing/selftests/kvm/lib/x86_64/tdx/tdcall.S
@@ -0,0 +1,90 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/* Adapted from arch/x86/coco/tdx/tdcall.S */
+
+#define TDX_HYPERCALL_r10 0 /* offsetof(struct tdx_hypercall_args, r10) */
+#define TDX_HYPERCALL_r11 8 /* offsetof(struct tdx_hypercall_args, r11) */
+#define TDX_HYPERCALL_r12 16 /* offsetof(struct tdx_hypercall_args, r12) */
+#define TDX_HYPERCALL_r13 24 /* offsetof(struct tdx_hypercall_args, r13) */
+#define TDX_HYPERCALL_r14 32 /* offsetof(struct tdx_hypercall_args, r14) */
+#define TDX_HYPERCALL_r15 40 /* offsetof(struct tdx_hypercall_args, r15) */
+
+/*
+ * Bitmasks of exposed registers (with VMM).
+ */
+#define TDX_R10 0x400
+#define TDX_R11 0x800
+#define TDX_R12 0x1000
+#define TDX_R13 0x2000
+#define TDX_R14 0x4000
+#define TDX_R15 0x8000
+
+#define TDX_HCALL_HAS_OUTPUT 0x1
+
+/*
+ * These registers are clobbered to hold arguments for each
+ * TDVMCALL. They are safe to expose to the VMM.
+ * Each bit in this mask represents a register ID. Bit field
+ * details can be found in TDX GHCI specification, section
+ * titled "TDCALL [TDG.VP.VMCALL] leaf".
+ */
+#define TDVMCALL_EXPOSE_REGS_MASK ( TDX_R10 | TDX_R11 | \
+ TDX_R12 | TDX_R13 | \
+ TDX_R14 | TDX_R15 )
+
+.code64
+.section .text
+
+.globl __tdx_hypercall
+.type __tdx_hypercall, @function
+__tdx_hypercall:
+ /* Set up stack frame */
+ push %rbp
+ movq %rsp, %rbp
+
+ /* Save callee-saved GPRs as mandated by the x86_64 ABI */
+ push %r15
+ push %r14
+ push %r13
+ push %r12
+
+ /* Mangle function call ABI into TDCALL ABI: */
+ /* Set TDCALL leaf ID (TDVMCALL (0)) in RAX */
+ xor %eax, %eax
+
+ /* Copy hypercall registers from arg struct: */
+ movq TDX_HYPERCALL_r10(%rdi), %r10
+ movq TDX_HYPERCALL_r11(%rdi), %r11
+ movq TDX_HYPERCALL_r12(%rdi), %r12
+ movq TDX_HYPERCALL_r13(%rdi), %r13
+ movq TDX_HYPERCALL_r14(%rdi), %r14
+ movq TDX_HYPERCALL_r15(%rdi), %r15
+
+ movl $TDVMCALL_EXPOSE_REGS_MASK, %ecx
+
+ tdcall
+
+ /* TDVMCALL leaf return code is in R10 */
+ movq %r10, %rax
+
+ /* Copy hypercall result registers to arg struct if needed */
+ testq $TDX_HCALL_HAS_OUTPUT, %rsi
+ jz .Lout
+
+ movq %r10, TDX_HYPERCALL_r10(%rdi)
+ movq %r11, TDX_HYPERCALL_r11(%rdi)
+ movq %r12, TDX_HYPERCALL_r12(%rdi)
+ movq %r13, TDX_HYPERCALL_r13(%rdi)
+ movq %r14, TDX_HYPERCALL_r14(%rdi)
+ movq %r15, TDX_HYPERCALL_r15(%rdi)
+.Lout:
+ /* Restore callee-saved GPRs as mandated by the x86_64 ABI */
+ pop %r12
+ pop %r13
+ pop %r14
+ pop %r15
+
+ pop %rbp
+ ret
+
+/* Disable executable stack */
+.section .note.GNU-stack,"",%progbits
diff --git a/tools/testing/selftests/kvm/lib/x86_64/tdx/tdx.c b/tools/testing/selftests/kvm/lib/x86_64/tdx/tdx.c
new file mode 100644
index 0000000000000..c2414523487a7
--- /dev/null
+++ b/tools/testing/selftests/kvm/lib/x86_64/tdx/tdx.c
@@ -0,0 +1,27 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include "tdx/tdcall.h"
+#include "tdx/tdx.h"
+
+uint64_t tdg_vp_vmcall_instruction_io(uint64_t port, uint64_t size,
+ uint64_t write, uint64_t *data)
+{
+ uint64_t ret;
+ struct tdx_hypercall_args args = {
+ .r10 = TDX_HYPERCALL_STANDARD,
+ .r11 = TDG_VP_VMCALL_INSTRUCTION_IO,
+ .r12 = size,
+ .r13 = write,
+ .r14 = port,
+ };
+
+ if (write)
+ args.r15 = *data;
+
+ ret = __tdx_hypercall(&args, write ? 0 : TDX_HCALL_HAS_OUTPUT);
+
+ if (!write)
+ *data = args.r11;
+
+ return ret;
+}
diff --git a/tools/testing/selftests/kvm/lib/x86_64/tdx/test_util.c b/tools/testing/selftests/kvm/lib/x86_64/tdx/test_util.c
new file mode 100644
index 0000000000000..6905d0ca38774
--- /dev/null
+++ b/tools/testing/selftests/kvm/lib/x86_64/tdx/test_util.c
@@ -0,0 +1,34 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+#include "kvm_util_base.h"
+#include "tdx/tdx.h"
+#include "tdx/test_util.h"
+
+void run_in_new_process(void (*func)(void))
+{
+ if (fork() == 0) {
+ func();
+ exit(0);
+ }
+ wait(NULL);
+}
+
+bool is_tdx_enabled(void)
+{
+ return !!(kvm_check_cap(KVM_CAP_VM_TYPES) & BIT(KVM_X86_TDX_VM));
+}
+
+void tdx_test_success(void)
+{
+ uint64_t code = 0;
+
+ tdg_vp_vmcall_instruction_io(TDX_TEST_SUCCESS_PORT,
+ TDX_TEST_SUCCESS_SIZE,
+ TDG_VP_VMCALL_INSTRUCTION_IO_WRITE, &code);
+}
diff --git a/tools/testing/selftests/kvm/x86_64/tdx_vm_tests.c b/tools/testing/selftests/kvm/x86_64/tdx_vm_tests.c
new file mode 100644
index 0000000000000..a18d1c9d60264
--- /dev/null
+++ b/tools/testing/selftests/kvm/x86_64/tdx_vm_tests.c
@@ -0,0 +1,45 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <signal.h>
+#include "kvm_util_base.h"
+#include "tdx/tdx_util.h"
+#include "tdx/test_util.h"
+#include "test_util.h"
+
+void guest_code_lifecycle(void)
+{
+ tdx_test_success();
+}
+
+void verify_td_lifecycle(void)
+{
+ struct kvm_vm *vm;
+ struct kvm_vcpu *vcpu;
+
+ vm = td_create();
+ td_initialize(vm, VM_MEM_SRC_ANONYMOUS, 0);
+ vcpu = td_vcpu_add(vm, 0, guest_code_lifecycle);
+ td_finalize(vm);
+
+ printf("Verifying TD lifecycle:\n");
+
+ vcpu_run(vcpu);
+ TDX_TEST_ASSERT_SUCCESS(vcpu);
+
+ kvm_vm_free(vm);
+ printf("\t ... PASSED\n");
+}
+
+int main(int argc, char **argv)
+{
+ setbuf(stdout, NULL);
+
+ if (!is_tdx_enabled()) {
+ print_skip("TDX is not supported by the KVM");
+ exit(KSFT_SKIP);
+ }
+
+ run_in_new_process(&verify_td_lifecycle);
+
+ return 0;
+}
--
2.39.0.246.g2a6d74b583-goog