[RFC PATCH v3 24/31] KVM: selftests: TDX: Add shared memory test

Ackerley Tng
2023-01-21T00:19:39Z

From: Ryan Afranji <afranji@google.com>

Adds a test that sets up shared memory between the host and guest.

Signed-off-by: Ryan Afranji <afranji@google.com>
Signed-off-by: Sagi Shahar <sagis@google.com>
Signed-off-by: Ackerley Tng <ackerleytng@google.com>
---
tools/testing/selftests/kvm/.gitignore | 1 +
tools/testing/selftests/kvm/Makefile | 1 +
.../selftests/kvm/include/x86_64/tdx/tdx.h | 2 +
.../kvm/include/x86_64/tdx/tdx_util.h | 3 +
.../selftests/kvm/lib/x86_64/tdx/tdx.c | 16 ++
.../selftests/kvm/lib/x86_64/tdx/tdx_util.c | 30 ++++
.../kvm/x86_64/tdx_shared_mem_test.c | 137 ++++++++++++++++++
7 files changed, 190 insertions(+)
create mode 100644 tools/testing/selftests/kvm/x86_64/tdx_shared_mem_test.c

diff --git a/tools/testing/selftests/kvm/.gitignore b/tools/testing/selftests/kvm/.gitignore
index 370d6430b32b4..e1663b0f809b4 100644
--- a/tools/testing/selftests/kvm/.gitignore
+++ b/tools/testing/selftests/kvm/.gitignore
@@ -66,6 +66,7 @@
/x86_64/vmx_pmu_caps_test
/x86_64/triple_fault_event_test
/x86_64/tdx_vm_tests
+/x86_64/tdx_shared_mem_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 9f289322a4933..27e9148212fa5 100644
--- a/tools/testing/selftests/kvm/Makefile
+++ b/tools/testing/selftests/kvm/Makefile
@@ -152,6 +152,7 @@ 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
+TEST_GEN_PROGS_x86_64 += x86_64/tdx_shared_mem_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/include/x86_64/tdx/tdx.h b/tools/testing/selftests/kvm/include/x86_64/tdx/tdx.h
index ffab2c3ca312b..857a297e51ac6 100644
--- a/tools/testing/selftests/kvm/include/x86_64/tdx/tdx.h
+++ b/tools/testing/selftests/kvm/include/x86_64/tdx/tdx.h
@@ -7,6 +7,7 @@
#define TDG_VP_INFO 1

#define TDG_VP_VMCALL_GET_TD_VM_CALL_INFO 0x10000
+#define TDG_VP_VMCALL_MAP_GPA 0x10001
#define TDG_VP_VMCALL_REPORT_FATAL_ERROR 0x10003

#define TDG_VP_VMCALL_INSTRUCTION_CPUID 10
@@ -36,5 +37,6 @@ uint64_t tdg_vp_vmcall_instruction_cpuid(uint32_t eax, uint32_t ecx,
uint64_t tdg_vp_info(uint64_t *rcx, uint64_t *rdx,
uint64_t *r8, uint64_t *r9,
uint64_t *r10, uint64_t *r11);
+uint64_t tdg_vp_vmcall_map_gpa(uint64_t address, uint64_t size, uint64_t *data_out);

#endif // SELFTEST_TDX_TDX_H
diff --git a/tools/testing/selftests/kvm/include/x86_64/tdx/tdx_util.h b/tools/testing/selftests/kvm/include/x86_64/tdx/tdx_util.h
index 274b245f200bf..58374453b4b7e 100644
--- a/tools/testing/selftests/kvm/include/x86_64/tdx/tdx_util.h
+++ b/tools/testing/selftests/kvm/include/x86_64/tdx/tdx_util.h
@@ -13,4 +13,7 @@ void td_initialize(struct kvm_vm *vm, enum vm_mem_backing_src_type src_type,
uint64_t attributes);
void td_finalize(struct kvm_vm *vm);

+void handle_memory_conversion(struct kvm_vm *vm, uint64_t gpa, uint64_t size,
+ bool shared_to_private);
+
#endif // SELFTESTS_TDX_KVM_UTIL_H
diff --git a/tools/testing/selftests/kvm/lib/x86_64/tdx/tdx.c b/tools/testing/selftests/kvm/lib/x86_64/tdx/tdx.c
index a280136634d3b..e0a39f29a0662 100644
--- a/tools/testing/selftests/kvm/lib/x86_64/tdx/tdx.c
+++ b/tools/testing/selftests/kvm/lib/x86_64/tdx/tdx.c
@@ -189,3 +189,19 @@ uint64_t tdg_vp_info(uint64_t *rcx, uint64_t *rdx,

return ret;
}
+
+uint64_t tdg_vp_vmcall_map_gpa(uint64_t address, uint64_t size, uint64_t *data_out)
+{
+ uint64_t ret;
+ struct tdx_hypercall_args args = {
+ .r11 = TDG_VP_VMCALL_MAP_GPA,
+ .r12 = address,
+ .r13 = size
+ };
+
+ ret = __tdx_hypercall(&args, TDX_HCALL_HAS_OUTPUT);
+
+ if (data_out)
+ *data_out = args.r11;
+ return ret;
+}
diff --git a/tools/testing/selftests/kvm/lib/x86_64/tdx/tdx_util.c b/tools/testing/selftests/kvm/lib/x86_64/tdx/tdx_util.c
index 2e9679d24a843..4d6615b97770a 100644
--- a/tools/testing/selftests/kvm/lib/x86_64/tdx/tdx_util.c
+++ b/tools/testing/selftests/kvm/lib/x86_64/tdx/tdx_util.c
@@ -505,3 +505,33 @@ void td_finalize(struct kvm_vm *vm)

tdx_td_finalizemr(vm);
}
+
+/**
+ * Handle conversion of memory with @size beginning @gpa for @vm. Set
+ * @shared_to_private to true for shared to private conversions and false
+ * otherwise.
+ *
+ * Since this is just for selftests, we will just keep both pieces of backing
+ * memory allocated and not deallocate/allocate memory; we'll just do the
+ * minimum of calling KVM_MEMORY_ENCRYPT_REG_REGION and
+ * KVM_MEMORY_ENCRYPT_UNREG_REGION.
+ */
+void handle_memory_conversion(struct kvm_vm *vm, uint64_t gpa, uint64_t size,
+ bool shared_to_private)
+{
+ struct kvm_enc_region range;
+ char *ioctl_string = shared_to_private
+ ? "KVM_MEMORY_ENCRYPT_REG_REGION"
+ : "KVM_MEMORY_ENCRYPT_UNREG_REGION";
+
+ range.addr = gpa;
+ range.size = size;
+
+ printf("\t ... calling %s ioctl with gpa=%#lx, size=%#lx\n",
+ ioctl_string, gpa, size);
+
+ if (shared_to_private)
+ vm_ioctl(vm, KVM_MEMORY_ENCRYPT_REG_REGION, &range);
+ else
+ vm_ioctl(vm, KVM_MEMORY_ENCRYPT_UNREG_REGION, &range);
+}
diff --git a/tools/testing/selftests/kvm/x86_64/tdx_shared_mem_test.c b/tools/testing/selftests/kvm/x86_64/tdx_shared_mem_test.c
new file mode 100644
index 0000000000000..eb4cf64ae83a8
--- /dev/null
+++ b/tools/testing/selftests/kvm/x86_64/tdx_shared_mem_test.c
@@ -0,0 +1,137 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <linux/kvm.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"
+
+#define TDX_SHARED_MEM_TEST_PRIVATE_GVA (0x80000000)
+#define TDX_SHARED_MEM_TEST_VADDR_SHARED_MASK BIT_ULL(30)
+#define TDX_SHARED_MEM_TEST_SHARED_GVA \
+ (TDX_SHARED_MEM_TEST_PRIVATE_GVA | \
+ TDX_SHARED_MEM_TEST_VADDR_SHARED_MASK)
+
+#define TDX_SHARED_MEM_TEST_GUEST_WRITE_VALUE (0xcafecafe)
+#define TDX_SHARED_MEM_TEST_HOST_WRITE_VALUE (0xabcdabcd)
+
+#define TDX_SHARED_MEM_TEST_INFO_PORT 0x87
+
+/*
+ * Shared variables between guest and host
+ */
+static uint64_t test_mem_private_gpa;
+static uint64_t test_mem_shared_gpa;
+
+void guest_shared_mem(void)
+{
+ uint32_t *test_mem_shared_gva =
+ (uint32_t *)TDX_SHARED_MEM_TEST_SHARED_GVA;
+
+ uint64_t placeholder;
+ uint64_t ret;
+
+ /* Map gpa as shared */
+ ret = tdg_vp_vmcall_map_gpa(test_mem_shared_gpa, PAGE_SIZE,
+ &placeholder);
+ if (ret)
+ tdx_test_fatal_with_data(ret, __LINE__);
+
+ *test_mem_shared_gva = TDX_SHARED_MEM_TEST_GUEST_WRITE_VALUE;
+
+ /* Exit so host can read shared value */
+ ret = tdg_vp_vmcall_instruction_io(TDX_SHARED_MEM_TEST_INFO_PORT, 4,
+ TDG_VP_VMCALL_INSTRUCTION_IO_WRITE,
+ &placeholder);
+ if (ret)
+ tdx_test_fatal_with_data(ret, __LINE__);
+
+ /* Read value written by host and send it back out for verification */
+ ret = tdg_vp_vmcall_instruction_io(TDX_SHARED_MEM_TEST_INFO_PORT, 4,
+ TDG_VP_VMCALL_INSTRUCTION_IO_WRITE,
+ (uint64_t *)test_mem_shared_gva);
+ if (ret)
+ tdx_test_fatal_with_data(ret, __LINE__);
+}
+
+int verify_shared_mem(void)
+{
+ struct kvm_vm *vm;
+ struct kvm_vcpu *vcpu;
+
+ vm_vaddr_t test_mem_private_gva;
+ uint32_t *test_mem_hva;
+
+ vm = td_create();
+ td_initialize(vm, VM_MEM_SRC_ANONYMOUS, 0);
+ vcpu = td_vcpu_add(vm, 0, guest_shared_mem);
+
+ /*
+ * 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_mem_private_gva = vm_vaddr_alloc(vm, vm->page_size,
+ TDX_SHARED_MEM_TEST_PRIVATE_GVA);
+ ASSERT_EQ(test_mem_private_gva, TDX_SHARED_MEM_TEST_PRIVATE_GVA);
+
+ test_mem_hva = addr_gva2hva(vm, test_mem_private_gva);
+ TEST_ASSERT(test_mem_hva != NULL,
+ "Guest address not found in guest memory regions\n");
+
+ test_mem_private_gpa = addr_gva2gpa(vm, test_mem_private_gva);
+ virt_pg_map_shared(vm, TDX_SHARED_MEM_TEST_SHARED_GVA,
+ test_mem_private_gpa);
+
+ test_mem_shared_gpa = test_mem_private_gpa | BIT_ULL(vm->pa_bits - 1);
+ sync_global_to_guest(vm, test_mem_private_gpa);
+ sync_global_to_guest(vm, test_mem_shared_gpa);
+
+ td_finalize(vm);
+
+ printf("Verifying shared memory accesses for TDX\n");
+
+ /* Begin guest execution; guest writes to shared memory. */
+ printf("\t ... Starting guest execution\n");
+
+ /* Handle map gpa as shared */
+ /* TODO: MapGPA should exit to the host VMM, but now it doesn't */
+ // vcpu_run(vcpu);
+ // ASSERT_EQ(vcpu->run->exit_reason, KVM_EXIT_MEMORY_FAULT);
+ // handle_memory_conversion(vm, vcpu->run->memory.gpa, vcpu->run->memory.size,
+ // vcpu->run->memory.flags == KVM_MEMORY_EXIT_FLAG_PRIVATE);
+
+ vcpu_run(vcpu);
+ TDX_TEST_ASSERT_IO(vcpu, TDX_SHARED_MEM_TEST_INFO_PORT, 4,
+ TDG_VP_VMCALL_INSTRUCTION_IO_WRITE);
+ ASSERT_EQ(*test_mem_hva, TDX_SHARED_MEM_TEST_GUEST_WRITE_VALUE);
+
+ *test_mem_hva = TDX_SHARED_MEM_TEST_HOST_WRITE_VALUE;
+ vcpu_run(vcpu);
+ TDX_TEST_ASSERT_IO(vcpu, TDX_SHARED_MEM_TEST_INFO_PORT, 4,
+ TDG_VP_VMCALL_INSTRUCTION_IO_WRITE);
+ ASSERT_EQ(*(uint32_t *)((void *)vcpu->run + vcpu->run->io.data_offset),
+ TDX_SHARED_MEM_TEST_HOST_WRITE_VALUE);
+
+ printf("\t ... PASSED\n");
+
+ kvm_vm_free(vm);
+
+ return 0;
+}
+
+int main(int argc, char **argv)
+{
+ if (!is_tdx_enabled()) {
+ printf("TDX is not supported by the KVM\n"
+ "Skipping the TDX tests.\n");
+ return 0;
+ }
+
+ return verify_shared_mem();
+}
--
2.39.0.246.g2a6d74b583-goog