Re: [RFC PATCH v5 09/29] KVM: selftests: TDX: Add report_fatal_error test

[Sagi Shahar <sagis@google.com>]

On Fri, Mar 1, 2024 at 12:52 AM Binbin Wu <binbin.wu@linux.intel.com> wrote:
>
>
>
> On 12/13/2023 4:46 AM, Sagi Shahar wrote:
> > The test checks report_fatal_error functionality.
> >
> > 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/tdx.h    |  6 ++-
> >   .../kvm/include/x86_64/tdx/tdx_util.h         |  1 +
> >   .../kvm/include/x86_64/tdx/test_util.h        | 19 ++++++++
> >   .../selftests/kvm/lib/x86_64/tdx/tdx.c        | 39 ++++++++++++++++
> >   .../selftests/kvm/lib/x86_64/tdx/tdx_util.c   | 12 +++++
> >   .../selftests/kvm/lib/x86_64/tdx/test_util.c  | 10 +++++
> >   .../selftests/kvm/x86_64/tdx_vm_tests.c       | 45 +++++++++++++++++++
> >   7 files changed, 131 insertions(+), 1 deletion(-)
> >
> > 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 a7161efe4ee2..1340c1070002 100644
> > --- a/tools/testing/selftests/kvm/include/x86_64/tdx/tdx.h
> > +++ b/tools/testing/selftests/kvm/include/x86_64/tdx/tdx.h
> > @@ -3,10 +3,14 @@
> >   #define SELFTEST_TDX_TDX_H
> >
> >   #include <stdint.h>
> > +#include "kvm_util_base.h"
> >
> > -#define TDG_VP_VMCALL_INSTRUCTION_IO 30
> > +#define TDG_VP_VMCALL_REPORT_FATAL_ERROR 0x10003
> >
> > +#define TDG_VP_VMCALL_INSTRUCTION_IO 30
> > +void handle_userspace_tdg_vp_vmcall_exit(struct kvm_vcpu *vcpu);
> >   uint64_t tdg_vp_vmcall_instruction_io(uint64_t port, uint64_t size,
> >                                     uint64_t write, uint64_t *data);
> > +void tdg_vp_vmcall_report_fatal_error(uint64_t error_code, uint64_t data_gpa);
> >
> >   #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 274b245f200b..32dd6b8fda46 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
> > @@ -12,5 +12,6 @@ struct kvm_vm *td_create(void);
> >   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 td_vcpu_run(struct kvm_vcpu *vcpu);
> >
> >   #endif // SELFTESTS_TDX_KVM_UTIL_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 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);
> > +
> >   #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;
> > +
> > +     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);
>
> I find tdx_test_fatal() is called a lot and each call site checks the err
> before calling it. Is it simpler to move the check of err inside of
> tdx_test_fatal() so that the callers just call it without check it every
> time?
>
tdx_test_fatal is used for more cases than just testing error code but
we can add another higher level helper. Maybe tdx_assert_error.
>
> > +
> > +     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;
> >   }
>