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Message-ID: <0344d85f-d6ab-4d78-abac-d0293d71ef91@linux.intel.com>
Date: Mon, 4 Mar 2024 17:16:53 +0800
From: Binbin Wu <binbin.wu@...ux.intel.com>
To: Yan Zhao <yan.y.zhao@...el.com>, Sagi Shahar <sagis@...gle.com>
Cc: linux-kselftest@...r.kernel.org, Ackerley Tng <ackerleytng@...gle.com>,
Ryan Afranji <afranji@...gle.com>, Erdem Aktas <erdemaktas@...gle.com>,
Isaku Yamahata <isaku.yamahata@...el.com>,
Sean Christopherson <seanjc@...gle.com>, Paolo Bonzini
<pbonzini@...hat.com>, Shuah Khan <shuah@...nel.org>,
Peter Gonda <pgonda@...gle.com>, Haibo Xu <haibo1.xu@...el.com>,
Chao Peng <chao.p.peng@...ux.intel.com>,
Vishal Annapurve <vannapurve@...gle.com>, Roger Wang <runanwang@...gle.com>,
Vipin Sharma <vipinsh@...gle.com>, jmattson@...gle.com, dmatlack@...gle.com,
linux-kernel@...r.kernel.org, kvm@...r.kernel.org, linux-mm@...ck.org
Subject: Re: [RFC PATCH v5 10/29] KVM: selftests: TDX: Adding test case for
TDX port IO
On 3/4/2024 10:19 AM, Yan Zhao wrote:
> On Tue, Dec 12, 2023 at 12:46:25PM -0800, Sagi Shahar wrote:
>> From: Erdem Aktas <erdemaktas@...gle.com>
>>
>> Verifies TDVMCALL<INSTRUCTION.IO> READ and WRITE operations.
>>
>> Signed-off-by: Erdem Aktas <erdemaktas@...gle.com>
>> Signed-off-by: Sagi Shahar <sagis@...gle.com>
>> Signed-off-by: Ackerley Tng <ackerleytng@...gle.com>
>> Signed-off-by: Ryan Afranji <afranji@...gle.com>
>> ---
>> .../kvm/include/x86_64/tdx/test_util.h | 34 ++++++++
>> .../selftests/kvm/x86_64/tdx_vm_tests.c | 82 +++++++++++++++++++
>> 2 files changed, 116 insertions(+)
>>
>> 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 6d69921136bd..95a5d5be7f0b 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
>> @@ -9,6 +9,40 @@
>> #define TDX_TEST_SUCCESS_PORT 0x30
>> #define TDX_TEST_SUCCESS_SIZE 4
>>
>> +/**
>> + * Assert that some IO operation involving tdg_vp_vmcall_instruction_io() was
>> + * called in the guest.
>> + */
>> +#define TDX_TEST_ASSERT_IO(VCPU, PORT, SIZE, DIR) \
>> + do { \
>> + TEST_ASSERT((VCPU)->run->exit_reason == KVM_EXIT_IO, \
>> + "Got exit_reason other than KVM_EXIT_IO: %u (%s)\n", \
>> + (VCPU)->run->exit_reason, \
>> + exit_reason_str((VCPU)->run->exit_reason)); \
>> + \
>> + TEST_ASSERT(((VCPU)->run->exit_reason == KVM_EXIT_IO) && \
>> + ((VCPU)->run->io.port == (PORT)) && \
>> + ((VCPU)->run->io.size == (SIZE)) && \
>> + ((VCPU)->run->io.direction == (DIR)), \
>> + "Got unexpected IO exit values: %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); \
>> + } 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.
>> + */
>> +#define TDX_TEST_CHECK_GUEST_FAILURE(VCPU) \
>> + do { \
>> + if ((VCPU)->run->exit_reason == KVM_EXIT_SYSTEM_EVENT) \
>> + TEST_FAIL("Guest reported error. error code: %lld (0x%llx)\n", \
>> + (VCPU)->run->system_event.data[1], \
>> + (VCPU)->run->system_event.data[1]); \
>> + } while (0)
>> +
>> /**
>> * Assert that tdx_test_success() was called in the guest.
>> */
>> 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 8638c7bbedaa..75467c407ca7 100644
>> --- a/tools/testing/selftests/kvm/x86_64/tdx_vm_tests.c
>> +++ b/tools/testing/selftests/kvm/x86_64/tdx_vm_tests.c
>> @@ -2,6 +2,7 @@
>>
>> #include <signal.h>
>> #include "kvm_util_base.h"
>> +#include "tdx/tdcall.h"
>> #include "tdx/tdx.h"
>> #include "tdx/tdx_util.h"
>> #include "tdx/test_util.h"
>> @@ -74,6 +75,86 @@ void verify_report_fatal_error(void)
>> printf("\t ... PASSED\n");
>> }
>>
>> +#define TDX_IOEXIT_TEST_PORT 0x50
>> +
>> +/*
>> + * Verifies IO functionality by writing a |value| to a predefined port.
>> + * Verifies that the read value is |value| + 1 from the same port.
>> + * If all the tests are passed then write a value to port TDX_TEST_PORT
>> + */
>> +void guest_ioexit(void)
>> +{
>> + uint64_t data_out, data_in, delta;
>> + uint64_t ret;
>> +
>> + data_out = 0xAB;
>> + ret = tdg_vp_vmcall_instruction_io(TDX_IOEXIT_TEST_PORT, 1,
>> + TDG_VP_VMCALL_INSTRUCTION_IO_WRITE,
>> + &data_out);
>> + if (ret)
>> + tdx_test_fatal(ret);
>> +
>> + ret = tdg_vp_vmcall_instruction_io(TDX_IOEXIT_TEST_PORT, 1,
>> + TDG_VP_VMCALL_INSTRUCTION_IO_READ,
>> + &data_in);
>> + if (ret)
>> + tdx_test_fatal(ret);
>> +
>> + delta = data_in - data_out;
>> + if (delta != 1)
>> + tdx_test_fatal(ret);
>> +
>> + tdx_test_success();
>> +}
>> +
>> +void verify_td_ioexit(void)
>> +{
>> + struct kvm_vm *vm;
>> + struct kvm_vcpu *vcpu;
>> +
>> + uint32_t port_data;
>> +
>> + vm = td_create();
>> + td_initialize(vm, VM_MEM_SRC_ANONYMOUS, 0);
>> + vcpu = td_vcpu_add(vm, 0, guest_ioexit);
>> + td_finalize(vm);
>> +
>> + printf("Verifying TD IO Exit:\n");
>> +
>> + /* Wait for guest to do a IO write */
>> + td_vcpu_run(vcpu);
>> + TDX_TEST_CHECK_GUEST_FAILURE(vcpu);
> This check is a vain, because the first VMExit from vcpu run is always
> KVM_EXIT_IO caused by tdg_vp_vmcall_instruction_io().
I think tdg_vp_vmcall_instruction_io() could fail if RCX (GPR select)
doesn't
meet the requirement (some bits must be 0).
Although RCX is set by guest code (in selftest, it set in __tdx_hypercall())
and it will not trigger the error, it still can be used as a guard to make
sure guest doesn't pass a invalid RCX.
>
>
>> + TDX_TEST_ASSERT_IO(vcpu, TDX_IOEXIT_TEST_PORT, 1,
>> + TDG_VP_VMCALL_INSTRUCTION_IO_WRITE);
>> + port_data = *(uint8_t *)((void *)vcpu->run + vcpu->run->io.data_offset);
>> +
>> + printf("\t ... IO WRITE: OK\n");
> So, even if there's an error in emulating writing of TDX_IOEXIT_TEST_PORT,
> and guest would then find a failure and trigger tdx_test_fatal(), this line
> will still print "IO WRITE: OK", which is not right.
>
>> +
>> + /*
>> + * Wait for the guest to do a IO read. Provide the previous written data
>> + * + 1 back to the guest
>> + */
>> + td_vcpu_run(vcpu);
>> + TDX_TEST_CHECK_GUEST_FAILURE(vcpu);
> This check is a vain, too, as in write case.
>
>> + TDX_TEST_ASSERT_IO(vcpu, TDX_IOEXIT_TEST_PORT, 1,
>> + TDG_VP_VMCALL_INSTRUCTION_IO_READ);
>> + *(uint8_t *)((void *)vcpu->run + vcpu->run->io.data_offset) = port_data + 1;
>> +
>> + printf("\t ... IO READ: OK\n");
> Same as in write case, this line should not be printed until after guest
> finishing checking return code.
>
>> +
>> + /*
>> + * Wait for the guest to complete execution successfully. The read
>> + * value is checked within the guest.
>> + */
>> + td_vcpu_run(vcpu);
>> + TDX_TEST_CHECK_GUEST_FAILURE(vcpu);
>> + TDX_TEST_ASSERT_SUCCESS(vcpu);
>> +
>> + printf("\t ... IO verify read/write values: OK\n");
>> + kvm_vm_free(vm);
>> + printf("\t ... PASSED\n");
>> +}
>> +
>> int main(int argc, char **argv)
>> {
>> setbuf(stdout, NULL);
>> @@ -85,6 +166,7 @@ int main(int argc, char **argv)
>>
>> run_in_new_process(&verify_td_lifecycle);
>> run_in_new_process(&verify_report_fatal_error);
>> + run_in_new_process(&verify_td_ioexit);
>>
>> return 0;
>> }
>> --
>> 2.43.0.472.g3155946c3a-goog
>>
>>
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