Re: [RFC PATCH v5 09/29] KVM: selftests: TDX: Add report_fatal_error test
From: Yan Zhao
Date: Fri Mar 01 2024 - 07:40:07 EST
..
> 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 b570b6d978ff..6d69921136bd 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
> @@ -49,4 +49,23 @@ bool is_tdx_enabled(void);
> */
> void tdx_test_success(void);
>
> +/**
> + * Report an error with @error_code to userspace.
> + *
> + * Return value from tdg_vp_vmcall_report_fatal_error is ignored since execution
> + * is not expected to continue beyond this point.
> + */
> +void tdx_test_fatal(uint64_t error_code);
> +
> +/**
> + * Report an error with @error_code to userspace.
> + *
> + * @data_gpa may point to an optional shared guest memory holding the error
> + * string.
> + *
> + * Return value from tdg_vp_vmcall_report_fatal_error is ignored since execution
> + * is not expected to continue beyond this point.
> + */
> +void tdx_test_fatal_with_data(uint64_t error_code, uint64_t data_gpa);
I found nowhere is using "data_gpa" as a gpa, even in patch 23, it's
usage is to pass a line number ("tdx_test_fatal_with_data(ret, __LINE__)").
> #endif // SELFTEST_TDX_TEST_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 c2414523487a..b854c3aa34ff 100644
> --- a/tools/testing/selftests/kvm/lib/x86_64/tdx/tdx.c
> +++ b/tools/testing/selftests/kvm/lib/x86_64/tdx/tdx.c
> @@ -1,8 +1,31 @@
> // SPDX-License-Identifier: GPL-2.0-only
>
> +#include <string.h>
> +
> #include "tdx/tdcall.h"
> #include "tdx/tdx.h"
>
> +void handle_userspace_tdg_vp_vmcall_exit(struct kvm_vcpu *vcpu)
> +{
> + struct kvm_tdx_vmcall *vmcall_info = &vcpu->run->tdx.u.vmcall;
> + uint64_t vmcall_subfunction = vmcall_info->subfunction;
> +
> + switch (vmcall_subfunction) {
> + case TDG_VP_VMCALL_REPORT_FATAL_ERROR:
> + vcpu->run->exit_reason = KVM_EXIT_SYSTEM_EVENT;
> + vcpu->run->system_event.ndata = 3;
> + vcpu->run->system_event.data[0] =
> + TDG_VP_VMCALL_REPORT_FATAL_ERROR;
> + vcpu->run->system_event.data[1] = vmcall_info->in_r12;
> + vcpu->run->system_event.data[2] = vmcall_info->in_r13;
> + vmcall_info->status_code = 0;
> + break;
> + default:
> + TEST_FAIL("TD VMCALL subfunction %lu is unsupported.\n",
> + vmcall_subfunction);
> + }
> +}
> +
> uint64_t tdg_vp_vmcall_instruction_io(uint64_t port, uint64_t size,
> uint64_t write, uint64_t *data)
> {
> @@ -25,3 +48,19 @@ uint64_t tdg_vp_vmcall_instruction_io(uint64_t port, uint64_t size,
>
> return ret;
> }
> +
> +void tdg_vp_vmcall_report_fatal_error(uint64_t error_code, uint64_t data_gpa)
> +{
> + struct tdx_hypercall_args args;
> +
> + memset(&args, 0, sizeof(struct tdx_hypercall_args));
> +
> + if (data_gpa)
> + error_code |= 0x8000000000000000;
>
So, why this error_code needs to set bit 63?
> + args.r11 = TDG_VP_VMCALL_REPORT_FATAL_ERROR;
> + args.r12 = error_code;
> + args.r13 = data_gpa;
> +
> + __tdx_hypercall(&args, 0);
> +}
> 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 b302060049d5..d745bb6287c1 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
> @@ -10,6 +10,7 @@
>
> #include "kvm_util.h"
> #include "test_util.h"
> +#include "tdx/tdx.h"
> #include "tdx/td_boot.h"
> #include "kvm_util_base.h"
> #include "processor.h"
> @@ -519,3 +520,14 @@ void td_finalize(struct kvm_vm *vm)
>
> tdx_td_finalizemr(vm);
> }
> +
> +void td_vcpu_run(struct kvm_vcpu *vcpu)
> +{
> + vcpu_run(vcpu);
> +
> + /* Handle TD VMCALLs that require userspace handling. */
> + if (vcpu->run->exit_reason == KVM_EXIT_TDX &&
> + vcpu->run->tdx.type == KVM_EXIT_TDX_VMCALL) {
> + handle_userspace_tdg_vp_vmcall_exit(vcpu);
> + }
> +}
> 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
> index 6905d0ca3877..7f3cd8089cea 100644
> --- a/tools/testing/selftests/kvm/lib/x86_64/tdx/test_util.c
> +++ b/tools/testing/selftests/kvm/lib/x86_64/tdx/test_util.c
> @@ -32,3 +32,13 @@ void tdx_test_success(void)
> TDX_TEST_SUCCESS_SIZE,
> TDG_VP_VMCALL_INSTRUCTION_IO_WRITE, &code);
> }
> +
> +void tdx_test_fatal_with_data(uint64_t error_code, uint64_t data_gpa)
> +{
> + tdg_vp_vmcall_report_fatal_error(error_code, data_gpa);
> +}
> +
> +void tdx_test_fatal(uint64_t error_code)
> +{
> + tdx_test_fatal_with_data(error_code, 0);
> +}
> 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 a18d1c9d6026..8638c7bbedaa 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/tdx.h"
> #include "tdx/tdx_util.h"
> #include "tdx/test_util.h"
> #include "test_util.h"
> @@ -30,6 +31,49 @@ void verify_td_lifecycle(void)
> printf("\t ... PASSED\n");
> }
>
> +void guest_code_report_fatal_error(void)
> +{
> + uint64_t err;
> +
> + /*
> + * Note: err should follow the GHCI spec definition:
> + * bits 31:0 should be set to 0.
> + * bits 62:32 are used for TD-specific extended error code.
> + * bit 63 is used to mark additional information in shared memory.
> + */
> + err = 0x0BAAAAAD00000000;
> + if (err)
> + tdx_test_fatal(err);
> +
> + tdx_test_success();
> +}
> +void verify_report_fatal_error(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_report_fatal_error);
> + td_finalize(vm);
> +
> + printf("Verifying report_fatal_error:\n");
> +
> + td_vcpu_run(vcpu);
> +
> + TEST_ASSERT_EQ(vcpu->run->exit_reason, KVM_EXIT_SYSTEM_EVENT);
> + TEST_ASSERT_EQ(vcpu->run->system_event.ndata, 3);
> + TEST_ASSERT_EQ(vcpu->run->system_event.data[0], TDG_VP_VMCALL_REPORT_FATAL_ERROR);
> + TEST_ASSERT_EQ(vcpu->run->system_event.data[1], 0x0BAAAAAD00000000);
> + TEST_ASSERT_EQ(vcpu->run->system_event.data[2], 0);
> +
> + 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);
> @@ -40,6 +84,7 @@ int main(int argc, char **argv)
> }
>
> run_in_new_process(&verify_td_lifecycle);
> + run_in_new_process(&verify_report_fatal_error);
>
> return 0;
> }
> --
> 2.43.0.472.g3155946c3a-goog
>
>