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Date:   Tue, 12 Dec 2023 12:46:32 -0800
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Subject: [RFC PATCH v5 17/29] KVM: selftests: TDX: Add TDX MMIO reads test
From:   Sagi Shahar <sagis@google.com>
To:     linux-kselftest@vger.kernel.org,
        Ackerley Tng <ackerleytng@google.com>,
        Ryan Afranji <afranji@google.com>,
        Erdem Aktas <erdemaktas@google.com>,
        Sagi Shahar <sagis@google.com>,
        Isaku Yamahata <isaku.yamahata@intel.com>
Cc:     Sean Christopherson <seanjc@google.com>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Shuah Khan <shuah@kernel.org>, Peter Gonda <pgonda@google.com>,
        Haibo Xu <haibo1.xu@intel.com>,
        Chao Peng <chao.p.peng@linux.intel.com>,
        Vishal Annapurve <vannapurve@google.com>,
        Roger Wang <runanwang@google.com>,
        Vipin Sharma <vipinsh@google.com>, jmattson@google.com,
        dmatlack@google.com, linux-kernel@vger.kernel.org,
        kvm@vger.kernel.org, linux-mm@kvack.org
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Precedence: bulk

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

Signed-off-by: Sagi Shahar <sagis@google.com>
Signed-off-by: Ackerley Tng <ackerleytng@google.com>
Signed-off-by: Ryan Afranji <afranji@google.com>
---
 .../selftests/kvm/include/x86_64/tdx/tdcall.h |  2 +
 .../selftests/kvm/include/x86_64/tdx/tdx.h    |  3 +
 .../kvm/include/x86_64/tdx/test_util.h        | 23 +++++
 .../selftests/kvm/lib/x86_64/tdx/tdx.c        | 19 ++++
 .../selftests/kvm/x86_64/tdx_vm_tests.c       | 87 +++++++++++++++++++
 5 files changed, 134 insertions(+)

diff --git a/tools/testing/selftests/kvm/include/x86_64/tdx/tdcall.h b/tools/testing/selftests/kvm/include/x86_64/tdx/tdcall.h
index b5e94b7c48fa..95fcdbd8404e 100644
--- a/tools/testing/selftests/kvm/include/x86_64/tdx/tdcall.h
+++ b/tools/testing/selftests/kvm/include/x86_64/tdx/tdcall.h
@@ -9,6 +9,8 @@
 
 #define TDG_VP_VMCALL_INSTRUCTION_IO_READ 0
 #define TDG_VP_VMCALL_INSTRUCTION_IO_WRITE 1
+#define TDG_VP_VMCALL_VE_REQUEST_MMIO_READ 0
+#define TDG_VP_VMCALL_VE_REQUEST_MMIO_WRITE 1
 
 #define TDG_VP_VMCALL_SUCCESS 0x0000000000000000
 #define TDG_VP_VMCALL_INVALID_OPERAND 0x8000000000000000
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 b18e39d20498..13ce60df5684 100644
--- a/tools/testing/selftests/kvm/include/x86_64/tdx/tdx.h
+++ b/tools/testing/selftests/kvm/include/x86_64/tdx/tdx.h
@@ -12,6 +12,7 @@
 #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
 
 void handle_userspace_tdg_vp_vmcall_exit(struct kvm_vcpu *vcpu);
 uint64_t tdg_vp_vmcall_instruction_io(uint64_t port, uint64_t size,
@@ -22,5 +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_64/tdx/test_util.h b/tools/testing/selftests/kvm/include/x86_64/tdx/test_util.h
index 8a9b6a1bec3e..af412b764604 100644
--- a/tools/testing/selftests/kvm/include/x86_64/tdx/test_util.h
+++ b/tools/testing/selftests/kvm/include/x86_64/tdx/test_util.h
@@ -35,6 +35,29 @@
 			(VCPU)->run->io.direction);			\
 	} while (0)
 
+
+/**
+ * Assert that some MMIO operation involving TDG.VP.VMCALL <#VERequestMMIO> was
+ * called in the guest.
+ */
+#define TDX_TEST_ASSERT_MMIO(VCPU, ADDR, SIZE, DIR)			\
+	do {								\
+		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 == (ADDR)) &&	\
+			((VCPU)->run->mmio.len == (SIZE)) &&		\
+			((VCPU)->run->mmio.is_write == (DIR)),		\
+			"Got an unexpected MMIO exit values: %u (%s) %llu %d %d\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);			\
+	} while (0)
+
 /**
  * Check and report 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_64/tdx/tdx.c b/tools/testing/selftests/kvm/lib/x86_64/tdx/tdx.c
index 9485bafedc38..b19f07ebc0e7 100644
--- a/tools/testing/selftests/kvm/lib/x86_64/tdx/tdx.c
+++ b/tools/testing/selftests/kvm/lib/x86_64/tdx/tdx.c
@@ -124,3 +124,22 @@ 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)
+{
+	uint64_t ret;
+	struct tdx_hypercall_args args = {
+		.r11 = TDG_VP_VMCALL_VE_REQUEST_MMIO,
+		.r12 = size,
+		.r13 = TDG_VP_VMCALL_VE_REQUEST_MMIO_READ,
+		.r14 = address,
+	};
+
+	ret = __tdx_hypercall(&args, TDX_HCALL_HAS_OUTPUT);
+
+	if (data_out)
+		*data_out = args.r11;
+
+	return ret;
+}
diff --git a/tools/testing/selftests/kvm/x86_64/tdx_vm_tests.c b/tools/testing/selftests/kvm/x86_64/tdx_vm_tests.c
index 5fae4c6e5f95..48902b69d13e 100644
--- a/tools/testing/selftests/kvm/x86_64/tdx_vm_tests.c
+++ b/tools/testing/selftests/kvm/x86_64/tdx_vm_tests.c
@@ -799,6 +799,92 @@ 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
+
+void guest_mmio_reads(void)
+{
+	uint64_t data;
+	uint64_t ret;
+
+	ret = tdg_vp_vmcall_ve_request_mmio_read(TDX_MMIO_TEST_ADDR, 1, &data);
+	if (ret)
+		tdx_test_fatal(ret);
+	if (data != 0x12)
+		tdx_test_fatal(1);
+
+	ret = tdg_vp_vmcall_ve_request_mmio_read(TDX_MMIO_TEST_ADDR, 2, &data);
+	if (ret)
+		tdx_test_fatal(ret);
+	if (data != 0x1234)
+		tdx_test_fatal(2);
+
+	ret = tdg_vp_vmcall_ve_request_mmio_read(TDX_MMIO_TEST_ADDR, 4, &data);
+	if (ret)
+		tdx_test_fatal(ret);
+	if (data != 0x12345678)
+		tdx_test_fatal(4);
+
+	ret = tdg_vp_vmcall_ve_request_mmio_read(TDX_MMIO_TEST_ADDR, 8, &data);
+	if (ret)
+		tdx_test_fatal(ret);
+	if (data != 0x1234567890ABCDEF)
+		tdx_test_fatal(8);
+
+	// Read an invalid number of bytes.
+	ret = tdg_vp_vmcall_ve_request_mmio_read(TDX_MMIO_TEST_ADDR, 10, &data);
+	if (ret)
+		tdx_test_fatal(ret);
+
+	tdx_test_success();
+}
+
+/*
+ * Varifies guest MMIO reads.
+ */
+void verify_mmio_reads(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_mmio_reads);
+	td_finalize(vm);
+
+	printf("Verifying TD MMIO reads:\n");
+
+	td_vcpu_run(vcpu);
+	TDX_TEST_CHECK_GUEST_FAILURE(vcpu);
+	TDX_TEST_ASSERT_MMIO(vcpu, TDX_MMIO_TEST_ADDR, 1, TDG_VP_VMCALL_VE_REQUEST_MMIO_READ);
+	*(uint8_t *)vcpu->run->mmio.data = 0x12;
+
+	td_vcpu_run(vcpu);
+	TDX_TEST_CHECK_GUEST_FAILURE(vcpu);
+	TDX_TEST_ASSERT_MMIO(vcpu, TDX_MMIO_TEST_ADDR, 2, TDG_VP_VMCALL_VE_REQUEST_MMIO_READ);
+	*(uint16_t *)vcpu->run->mmio.data = 0x1234;
+
+	td_vcpu_run(vcpu);
+	TDX_TEST_CHECK_GUEST_FAILURE(vcpu);
+	TDX_TEST_ASSERT_MMIO(vcpu, TDX_MMIO_TEST_ADDR, 4, TDG_VP_VMCALL_VE_REQUEST_MMIO_READ);
+	*(uint32_t *)vcpu->run->mmio.data = 0x12345678;
+
+	td_vcpu_run(vcpu);
+	TDX_TEST_CHECK_GUEST_FAILURE(vcpu);
+	TDX_TEST_ASSERT_MMIO(vcpu, TDX_MMIO_TEST_ADDR, 8, TDG_VP_VMCALL_VE_REQUEST_MMIO_READ);
+	*(uint64_t *)vcpu->run->mmio.data = 0x1234567890ABCDEF;
+
+	td_vcpu_run(vcpu);
+	TEST_ASSERT_EQ(vcpu->run->exit_reason, KVM_EXIT_SYSTEM_EVENT);
+	TEST_ASSERT_EQ(vcpu->run->system_event.data[1], TDG_VP_VMCALL_INVALID_OPERAND);
+
+	td_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);
@@ -818,6 +904,7 @@ int main(int argc, char **argv)
 	run_in_new_process(&verify_guest_msr_writes);
 	run_in_new_process(&verify_guest_msr_reads);
 	run_in_new_process(&verify_guest_hlt);
+	run_in_new_process(&verify_mmio_reads);
 
 	return 0;
 }
-- 
2.43.0.472.g3155946c3a-goog