[PATCH v8 18/30] KVM: selftests: TDX: Add TDX MMIO reads test

[Sagi Shahar <sagis@google.com>]

The test verifies MMIO reads of various sizes from the host to the guest.

Co-developed-by: Isaku Yamahata <isaku.yamahata@intel.com>
Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
Signed-off-by: Sagi Shahar <sagis@google.com>
---
 .../selftests/kvm/include/x86/tdx/tdx.h       |  4 +
 .../selftests/kvm/include/x86/tdx/tdx_util.h  |  1 +
 .../selftests/kvm/include/x86/tdx/test_util.h | 11 +++
 tools/testing/selftests/kvm/lib/x86/tdx/tdx.c | 20 +++++
 .../selftests/kvm/lib/x86/tdx/test_util.c     | 19 ++++
 tools/testing/selftests/kvm/x86/tdx_vm_test.c | 89 ++++++++++++++++++-
 6 files changed, 143 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/kvm/include/x86/tdx/tdx.h b/tools/testing/selftests/kvm/include/x86/tdx/tdx.h
index b5831919a215..fa0b24873a8f 100644
--- a/tools/testing/selftests/kvm/include/x86/tdx/tdx.h
+++ b/tools/testing/selftests/kvm/include/x86/tdx/tdx.h
@@ -13,6 +13,7 @@
 #define TDG_VP_VMCALL_INSTRUCTION_IO 30
 #define TDG_VP_VMCALL_INSTRUCTION_RDMSR 31
 #define TDG_VP_VMCALL_INSTRUCTION_WRMSR 32
+#define TDG_VP_VMCALL_VE_REQUEST_MMIO 48
 
 uint64_t tdg_vp_vmcall_instruction_io(uint64_t port, uint64_t size,
 				      uint64_t write, uint64_t *data);
@@ -22,4 +23,7 @@ uint64_t tdg_vp_vmcall_get_td_vmcall_info(uint64_t *r11, uint64_t *r12,
 uint64_t tdg_vp_vmcall_instruction_rdmsr(uint64_t index, uint64_t *ret_value);
 uint64_t tdg_vp_vmcall_instruction_wrmsr(uint64_t index, uint64_t value);
 uint64_t tdg_vp_vmcall_instruction_hlt(uint64_t interrupt_blocked_flag);
+uint64_t tdg_vp_vmcall_ve_request_mmio_read(uint64_t address, uint64_t size,
+					    uint64_t *data_out);
+
 #endif // SELFTEST_TDX_TDX_H
diff --git a/tools/testing/selftests/kvm/include/x86/tdx/tdx_util.h b/tools/testing/selftests/kvm/include/x86/tdx/tdx_util.h
index d66cf17f03ea..c942aec7ad26 100644
--- a/tools/testing/selftests/kvm/include/x86/tdx/tdx_util.h
+++ b/tools/testing/selftests/kvm/include/x86/tdx/tdx_util.h
@@ -6,6 +6,7 @@
 
 #include "kvm_util.h"
 
+extern uint64_t tdx_s_bit;
 void tdx_filter_cpuid(struct kvm_vm *vm, struct kvm_cpuid2 *cpuid_data);
 void __tdx_mask_cpuid_features(struct kvm_cpuid_entry2 *entry);
 
diff --git a/tools/testing/selftests/kvm/include/x86/tdx/test_util.h b/tools/testing/selftests/kvm/include/x86/tdx/test_util.h
index 91031e956462..3330d5a54698 100644
--- a/tools/testing/selftests/kvm/include/x86/tdx/test_util.h
+++ b/tools/testing/selftests/kvm/include/x86/tdx/test_util.h
@@ -17,6 +17,10 @@
 #define PORT_READ	0
 #define PORT_WRITE	1
 
+/* MMIO direction */
+#define MMIO_READ	0
+#define MMIO_WRITE	1
+
 /*
  * Assert that some IO operation involving tdg_vp_vmcall_instruction_io() was
  * called in the guest.
@@ -24,6 +28,13 @@
 void tdx_test_assert_io(struct kvm_vcpu *vcpu, uint16_t port, uint8_t size,
 			uint8_t direction);
 
+/*
+ * Assert that some MMIO operation involving TDG.VP.VMCALL <#VERequestMMIO> was
+ * called in the guest.
+ */
+void tdx_test_assert_mmio(struct kvm_vcpu *vcpu, uint64_t phys_addr,
+			  uint32_t size, uint8_t is_write);
+
 /*
  * Run the tdx vcpu and check if there was some failure in the guest, either
  * an exception like a triple fault, or if a tdx_test_fatal() was hit.
diff --git a/tools/testing/selftests/kvm/lib/x86/tdx/tdx.c b/tools/testing/selftests/kvm/lib/x86/tdx/tdx.c
index e89ca727286e..8bf41e667fc1 100644
--- a/tools/testing/selftests/kvm/lib/x86/tdx/tdx.c
+++ b/tools/testing/selftests/kvm/lib/x86/tdx/tdx.c
@@ -4,6 +4,7 @@
 
 #include "tdx/tdcall.h"
 #include "tdx/tdx.h"
+#include "tdx/test_util.h"
 
 uint64_t tdg_vp_vmcall_instruction_io(uint64_t port, uint64_t size,
 				      uint64_t write, uint64_t *data)
@@ -103,3 +104,22 @@ uint64_t tdg_vp_vmcall_instruction_hlt(uint64_t interrupt_blocked_flag)
 
 	return __tdx_hypercall(&args, 0);
 }
+
+uint64_t tdg_vp_vmcall_ve_request_mmio_read(uint64_t address, uint64_t size,
+					    uint64_t *data_out)
+{
+	struct tdx_hypercall_args args = {
+		.r11 = TDG_VP_VMCALL_VE_REQUEST_MMIO,
+		.r12 = size,
+		.r13 = MMIO_READ,
+		.r14 = address,
+	};
+	uint64_t ret;
+
+	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/tdx/test_util.c b/tools/testing/selftests/kvm/lib/x86/tdx/test_util.c
index 8c3b6802c37e..f92ddda2d1ac 100644
--- a/tools/testing/selftests/kvm/lib/x86/tdx/test_util.c
+++ b/tools/testing/selftests/kvm/lib/x86/tdx/test_util.c
@@ -31,6 +31,25 @@ void tdx_test_assert_io(struct kvm_vcpu *vcpu, uint16_t port, uint8_t size,
 		    vcpu->run->io.direction);
 }
 
+void tdx_test_assert_mmio(struct kvm_vcpu *vcpu, uint64_t phys_addr,
+			  uint32_t size, uint8_t is_write)
+{
+	TEST_ASSERT(vcpu->run->exit_reason == KVM_EXIT_MMIO,
+		    "Got exit_reason other than KVM_EXIT_MMIO: %u (%s)\n",
+		    vcpu->run->exit_reason,
+		    exit_reason_str(vcpu->run->exit_reason));
+
+	TEST_ASSERT(vcpu->run->exit_reason == KVM_EXIT_MMIO &&
+		    vcpu->run->mmio.phys_addr == phys_addr &&
+		    vcpu->run->mmio.len == size &&
+		    vcpu->run->mmio.is_write == is_write,
+		    "Got an unexpected MMIO exit values: %u (%s) %llu %u %u\n",
+		    vcpu->run->exit_reason,
+		    exit_reason_str(vcpu->run->exit_reason),
+		    vcpu->run->mmio.phys_addr, vcpu->run->mmio.len,
+		    vcpu->run->mmio.is_write);
+}
+
 void tdx_run(struct kvm_vcpu *vcpu)
 {
 	td_vcpu_run(vcpu);
diff --git a/tools/testing/selftests/kvm/x86/tdx_vm_test.c b/tools/testing/selftests/kvm/x86/tdx_vm_test.c
index 720ef5e87071..563f1025c8a3 100644
--- a/tools/testing/selftests/kvm/x86/tdx_vm_test.c
+++ b/tools/testing/selftests/kvm/x86/tdx_vm_test.c
@@ -719,6 +719,91 @@ void verify_guest_hlt(void)
 	_verify_guest_hlt(0);
 }
 
+/* Pick any address that was not mapped into the guest to test MMIO */
+#define TDX_MMIO_TEST_ADDR 0x200000000
+#define MMIO_SYNC_VALUE 0x42
+
+void guest_mmio_reads(void)
+{
+	uint64_t mmio_test_addr = TDX_MMIO_TEST_ADDR | tdx_s_bit;
+	uint64_t data;
+	uint64_t ret;
+
+	ret = tdg_vp_vmcall_ve_request_mmio_read(mmio_test_addr, 1, &data);
+	tdx_assert_error(ret);
+	if (data != 0x12)
+		tdx_test_fatal(1);
+
+	ret = tdg_vp_vmcall_ve_request_mmio_read(mmio_test_addr, 2, &data);
+	tdx_assert_error(ret);
+	if (data != 0x1234)
+		tdx_test_fatal(2);
+
+	ret = tdg_vp_vmcall_ve_request_mmio_read(mmio_test_addr, 4, &data);
+	tdx_assert_error(ret);
+	if (data != 0x12345678)
+		tdx_test_fatal(4);
+
+	ret = tdg_vp_vmcall_ve_request_mmio_read(mmio_test_addr, 8, &data);
+	tdx_assert_error(ret);
+	if (data != 0x1234567890ABCDEF)
+		tdx_test_fatal(8);
+
+	/* Make sure host and guest are synced to the same point of execution */
+	tdx_test_report_to_user_space(MMIO_SYNC_VALUE);
+
+	/* Read an invalid number of bytes. */
+	ret = tdg_vp_vmcall_ve_request_mmio_read(mmio_test_addr, 10, &data);
+	tdx_assert_error(ret);
+
+	tdx_test_success();
+}
+
+/*
+ * Verifies guest MMIO reads.
+ */
+void verify_mmio_reads(void)
+{
+	struct kvm_vcpu *vcpu;
+	struct kvm_vm *vm;
+
+	vm = td_create();
+	td_initialize(vm, VM_MEM_SRC_ANONYMOUS, 0);
+	vcpu = td_vcpu_add(vm, 0, guest_mmio_reads);
+	td_finalize(vm);
+
+	printf("Verifying TD MMIO reads:\n");
+
+	tdx_run(vcpu);
+	tdx_test_assert_mmio(vcpu, TDX_MMIO_TEST_ADDR, 1, MMIO_READ);
+	*(uint8_t *)vcpu->run->mmio.data = 0x12;
+
+	tdx_run(vcpu);
+	tdx_test_assert_mmio(vcpu, TDX_MMIO_TEST_ADDR, 2, MMIO_READ);
+	*(uint16_t *)vcpu->run->mmio.data = 0x1234;
+
+	tdx_run(vcpu);
+	tdx_test_assert_mmio(vcpu, TDX_MMIO_TEST_ADDR, 4, MMIO_READ);
+	*(uint32_t *)vcpu->run->mmio.data = 0x12345678;
+
+	tdx_run(vcpu);
+	tdx_test_assert_mmio(vcpu, TDX_MMIO_TEST_ADDR, 8, MMIO_READ);
+	*(uint64_t *)vcpu->run->mmio.data = 0x1234567890ABCDEF;
+
+	tdx_run(vcpu);
+	TEST_ASSERT_EQ(tdx_test_read_report_from_guest(vcpu), MMIO_SYNC_VALUE);
+
+	td_vcpu_run(vcpu);
+	TEST_ASSERT_EQ(vcpu->run->exit_reason, KVM_EXIT_SYSTEM_EVENT);
+	TEST_ASSERT_EQ(vcpu->run->system_event.data[12], TDG_VP_VMCALL_INVALID_OPERAND);
+
+	tdx_run(vcpu);
+	tdx_test_assert_success(vcpu);
+
+	kvm_vm_free(vm);
+	printf("\t ... PASSED\n");
+}
+
 int main(int argc, char **argv)
 {
 	ksft_print_header();
@@ -726,7 +811,7 @@ int main(int argc, char **argv)
 	if (!is_tdx_enabled())
 		ksft_exit_skip("TDX is not supported by the KVM. Exiting.\n");
 
-	ksft_set_plan(10);
+	ksft_set_plan(11);
 	ksft_test_result(!run_in_new_process(&verify_td_lifecycle),
 			 "verify_td_lifecycle\n");
 	ksft_test_result(!run_in_new_process(&verify_report_fatal_error),
@@ -747,6 +832,8 @@ int main(int argc, char **argv)
 			 "verify_guest_msr_reads\n");
 	ksft_test_result(!run_in_new_process(&verify_guest_hlt),
 			 "verify_guest_hlt\n");
+	ksft_test_result(!run_in_new_process(&verify_mmio_reads),
+			 "verify_mmio_reads\n");
 
 	ksft_finished();
 	return 0;
-- 
2.51.0.rc0.155.g4a0f42376b-goog