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Message-ID: <CAAhR5DGuKBSpxmvC1URZJoZuD+_o7p1fTBOVZk3fjnaiWfGQ3A@mail.gmail.com>
Date: Wed, 20 Aug 2025 23:19:05 -0500
From: Sagi Shahar <sagis@...gle.com>
To: Binbin Wu <binbin.wu@...ux.intel.com>
Cc: linux-kselftest@...r.kernel.org, Paolo Bonzini <pbonzini@...hat.com>,
Shuah Khan <shuah@...nel.org>, Sean Christopherson <seanjc@...gle.com>,
Ackerley Tng <ackerleytng@...gle.com>, Ryan Afranji <afranji@...gle.com>,
Andrew Jones <ajones@...tanamicro.com>, Isaku Yamahata <isaku.yamahata@...el.com>,
Erdem Aktas <erdemaktas@...gle.com>, Rick Edgecombe <rick.p.edgecombe@...el.com>,
Roger Wang <runanwang@...gle.com>, Oliver Upton <oliver.upton@...ux.dev>,
"Pratik R. Sampat" <pratikrajesh.sampat@....com>, Reinette Chatre <reinette.chatre@...el.com>,
Ira Weiny <ira.weiny@...el.com>, linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Subject: Re: [PATCH v8 09/30] KVM: selftests: TDX: Add TDX lifecycle test
On Wed, Aug 13, 2025 at 5:36 AM Binbin Wu <binbin.wu@...ux.intel.com> wrote:
>
>
>
> On 8/8/2025 4:16 AM, Sagi Shahar wrote:
> > From: Erdem Aktas <erdemaktas@...gle.com>
> >
> > Adding a test to verify TDX lifecycle by creating a TD and running a
> > dummy TDG.VP.VMCALL <Instruction.IO> inside it.
> >
> > Co-developed-by: Sagi Shahar <sagis@...gle.com>
> > Signed-off-by: Sagi Shahar <sagis@...gle.com>
> > Co-developed-by: Ackerley Tng <ackerleytng@...gle.com>
> > Signed-off-by: Ackerley Tng <ackerleytng@...gle.com>
> > Co-developed-by: Reinette Chatre <reinette.chatre@...el.com>
> > Signed-off-by: Reinette Chatre <reinette.chatre@...el.com>
> > Signed-off-by: Erdem Aktas <erdemaktas@...gle.com>
> > Signed-off-by: Sagi Shahar <sagis@...gle.com>
> > ---
> > tools/testing/selftests/kvm/Makefile.kvm | 4 +
> > .../selftests/kvm/include/x86/tdx/tdcall.h | 32 +++++++
> > .../selftests/kvm/include/x86/tdx/tdx.h | 12 +++
> > .../selftests/kvm/include/x86/tdx/test_util.h | 41 ++++++++
> > .../selftests/kvm/lib/x86/tdx/tdcall.S | 95 +++++++++++++++++++
> > tools/testing/selftests/kvm/lib/x86/tdx/tdx.c | 27 ++++++
> > .../selftests/kvm/lib/x86/tdx/test_util.c | 61 ++++++++++++
> > tools/testing/selftests/kvm/x86/tdx_vm_test.c | 47 +++++++++
> > 8 files changed, 319 insertions(+)
> > create mode 100644 tools/testing/selftests/kvm/include/x86/tdx/tdcall.h
> > create mode 100644 tools/testing/selftests/kvm/include/x86/tdx/tdx.h
> > create mode 100644 tools/testing/selftests/kvm/include/x86/tdx/test_util.h
> > create mode 100644 tools/testing/selftests/kvm/lib/x86/tdx/tdcall.S
> > create mode 100644 tools/testing/selftests/kvm/lib/x86/tdx/tdx.c
> > create mode 100644 tools/testing/selftests/kvm/lib/x86/tdx/test_util.c
> > create mode 100644 tools/testing/selftests/kvm/x86/tdx_vm_test.c
>
> It's better to split the patch to the lib/utility part and the test case part.
>
I will split it in v9.
> >
> > diff --git a/tools/testing/selftests/kvm/Makefile.kvm b/tools/testing/selftests/kvm/Makefile.kvm
> > index b429c92e07d8..4a147d498bd2 100644
> > --- a/tools/testing/selftests/kvm/Makefile.kvm
> > +++ b/tools/testing/selftests/kvm/Makefile.kvm
> > @@ -31,6 +31,9 @@ LIBKVM_x86 += lib/x86/ucall.c
> > LIBKVM_x86 += lib/x86/vmx.c
> > LIBKVM_x86 += lib/x86/tdx/tdx_util.c
> > LIBKVM_x86 += lib/x86/tdx/td_boot.S
> > +LIBKVM_x86 += lib/x86/tdx/tdcall.S
> > +LIBKVM_x86 += lib/x86/tdx/tdx.c
> > +LIBKVM_x86 += lib/x86/tdx/test_util.c
> >
> > LIBKVM_arm64 += lib/arm64/gic.c
> > LIBKVM_arm64 += lib/arm64/gic_v3.c
> > @@ -148,6 +151,7 @@ TEST_GEN_PROGS_x86 += rseq_test
> > TEST_GEN_PROGS_x86 += steal_time
> > TEST_GEN_PROGS_x86 += system_counter_offset_test
> > TEST_GEN_PROGS_x86 += pre_fault_memory_test
> > +TEST_GEN_PROGS_x86 += x86/tdx_vm_test
> >
> > # Compiled outputs used by test targets
> > TEST_GEN_PROGS_EXTENDED_x86 += x86/nx_huge_pages_test
> > diff --git a/tools/testing/selftests/kvm/include/x86/tdx/tdcall.h b/tools/testing/selftests/kvm/include/x86/tdx/tdcall.h
> > new file mode 100644
> > index 000000000000..a6c966e93486
> > --- /dev/null
> > +++ b/tools/testing/selftests/kvm/include/x86/tdx/tdcall.h
> > @@ -0,0 +1,32 @@
> > +/* SPDX-License-Identifier: GPL-2.0-only */
> > +/* Adapted from arch/x86/include/asm/shared/tdx.h */
> > +
> > +#ifndef SELFTESTS_TDX_TDCALL_H
> > +#define SELFTESTS_TDX_TDCALL_H
> > +
> > +#include <linux/bits.h>
> > +#include <linux/types.h>
> > +
> > +#define TDX_HCALL_HAS_OUTPUT BIT(0)
> > +
> > +#define TDX_HYPERCALL_STANDARD 0
> > +
> > +/*
> > + * Used in __tdx_hypercall() to pass down and get back registers' values of
> > + * the TDCALL instruction when requesting services from the VMM.
> > + *
> > + * This is a software only structure and not part of the TDX module/VMM ABI.
> > + */
> > +struct tdx_hypercall_args {
> > + u64 r10;
> > + u64 r11;
> > + u64 r12;
> > + u64 r13;
> > + u64 r14;
> > + u64 r15;
> > +};
> > +
> > +/* Used to request services from the VMM */
> > +u64 __tdx_hypercall(struct tdx_hypercall_args *args, unsigned long flags);
> > +
> > +#endif // SELFTESTS_TDX_TDCALL_H
> > diff --git a/tools/testing/selftests/kvm/include/x86/tdx/tdx.h b/tools/testing/selftests/kvm/include/x86/tdx/tdx.h
> > new file mode 100644
> > index 000000000000..a7161efe4ee2
> > --- /dev/null
> > +++ b/tools/testing/selftests/kvm/include/x86/tdx/tdx.h
> > @@ -0,0 +1,12 @@
> > +/* SPDX-License-Identifier: GPL-2.0-only */
> > +#ifndef SELFTEST_TDX_TDX_H
> > +#define SELFTEST_TDX_TDX_H
> > +
> > +#include <stdint.h>
> > +
> > +#define TDG_VP_VMCALL_INSTRUCTION_IO 30
> > +
> > +uint64_t tdg_vp_vmcall_instruction_io(uint64_t port, uint64_t size,
> > + uint64_t write, uint64_t *data);
> > +
> > +#endif // SELFTEST_TDX_TDX_H
> > diff --git a/tools/testing/selftests/kvm/include/x86/tdx/test_util.h b/tools/testing/selftests/kvm/include/x86/tdx/test_util.h
> > new file mode 100644
> > index 000000000000..07d63bf1ffe1
> > --- /dev/null
> > +++ b/tools/testing/selftests/kvm/include/x86/tdx/test_util.h
> > @@ -0,0 +1,41 @@
> > +/* SPDX-License-Identifier: GPL-2.0-only */
> > +#ifndef SELFTEST_TDX_TEST_UTIL_H
> > +#define SELFTEST_TDX_TEST_UTIL_H
> > +
> > +#include <stdbool.h>
> > +
> > +#include "tdcall.h"
> > +
> > +#define TDX_TEST_SUCCESS_PORT 0x30
> > +#define TDX_TEST_SUCCESS_SIZE 4
> > +
> > +/* Port I/O direction */
> > +#define PORT_READ 0
> > +#define PORT_WRITE 1
> > +
> > +/*
> > + * Run a test in a new process.
> > + *
> > + * There might be multiple tests running and if one test fails, it will
> > + * prevent the subsequent tests to run due to how tests are failing with
> > + * TEST_ASSERT function. run_in_new_process() will run a test in a new process
> > + * context and wait for it to finish or fail to prevent TEST_ASSERT to kill the
> > + * main testing process.
> > + */
> > +int run_in_new_process(void (*func)(void));
> > +
> > +/*
> > + * Verify that the TDX is supported by KVM.
> > + */
> > +bool is_tdx_enabled(void);
> > +
> > +/*
> > + * Report test success to userspace.
> > + *
> > + * Use tdx_test_assert_success() to assert that this function was called in the
> > + * guest.
> > + */
> > +void tdx_test_success(void);
> > +void tdx_test_assert_success(struct kvm_vcpu *vcpu);
> > +
> > +#endif // SELFTEST_TDX_TEST_UTIL_H
> > diff --git a/tools/testing/selftests/kvm/lib/x86/tdx/tdcall.S b/tools/testing/selftests/kvm/lib/x86/tdx/tdcall.S
> > new file mode 100644
> > index 000000000000..b10769d1d557
> > --- /dev/null
> > +++ b/tools/testing/selftests/kvm/lib/x86/tdx/tdcall.S
> > @@ -0,0 +1,95 @@
> > +/* SPDX-License-Identifier: GPL-2.0-only */
> > +/* Adapted from arch/x86/coco/tdx/tdcall.S */
> > +
> > +/*
> > + * TDCALL is supported in Binutils >= 2.36, add it for older version.
> > + */
> > +#define tdcall .byte 0x66,0x0f,0x01,0xcc
> > +
> > +#define TDX_HYPERCALL_r10 0 /* offsetof(struct tdx_hypercall_args, r10) */
> > +#define TDX_HYPERCALL_r11 8 /* offsetof(struct tdx_hypercall_args, r11) */
> > +#define TDX_HYPERCALL_r12 16 /* offsetof(struct tdx_hypercall_args, r12) */
> > +#define TDX_HYPERCALL_r13 24 /* offsetof(struct tdx_hypercall_args, r13) */
> > +#define TDX_HYPERCALL_r14 32 /* offsetof(struct tdx_hypercall_args, r14) */
> > +#define TDX_HYPERCALL_r15 40 /* offsetof(struct tdx_hypercall_args, r15) */
> > +
>
> As Sean suggested in an earlier patch, replicating the functionality of the
> kernel's OFFSET() could remove the hard-coded offset.
>
> > +/*
> > + * Bitmasks of exposed registers (with VMM).
> > + */
> > +#define TDX_R10 0x400
> > +#define TDX_R11 0x800
> > +#define TDX_R12 0x1000
> > +#define TDX_R13 0x2000
> > +#define TDX_R14 0x4000
> > +#define TDX_R15 0x8000
>
> Is BIT() better?
>
Done. Initially I had a problem including <linux/bits.h> here but I
ended up defining __ASSEMBLY__ manually to solve the issue.
> > +
> > +#define TDX_HCALL_HAS_OUTPUT 0x1
> > +
> > +/*
> > + * These registers are clobbered to hold arguments for each
> > + * TDVMCALL. They are safe to expose to the VMM.
> > + * Each bit in this mask represents a register ID. Bit field
> > + * details can be found in TDX GHCI specification, section
> > + * titled "TDCALL [TDG.VP.VMCALL] leaf".
> > + */
> > +#define TDVMCALL_EXPOSE_REGS_MASK ( TDX_R10 | TDX_R11 | \
> > + TDX_R12 | TDX_R13 | \
> > + TDX_R14 | TDX_R15 )
>
> #define TDVMCALL_EXPOSE_REGS_MASK \
> (TDX_R10 | TDX_R11 | TDX_R12 | TDX_R13 | TDX_R14 | TDX_R15)
>
> to save one line?
Done.
> > +
> > +.code64
> > +.section .text
> > +
> > +.globl __tdx_hypercall
> > +.type __tdx_hypercall, @function
> > +__tdx_hypercall:
> > + /* Set up stack frame */
> > + push %rbp
> > + movq %rsp, %rbp
> > +
> > + /* Save callee-saved GPRs as mandated by the x86_64 ABI */
> > + push %r15
> > + push %r14
> > + push %r13
> > + push %r12
> > +
> > + /* Mangle function call ABI into TDCALL ABI: */
> > + /* Set TDCALL leaf ID (TDVMCALL (0)) in RAX */
> > + xor %eax, %eax
> > +
> > + /* Copy hypercall registers from arg struct: */
> > + movq TDX_HYPERCALL_r10(%rdi), %r10
> > + movq TDX_HYPERCALL_r11(%rdi), %r11
> > + movq TDX_HYPERCALL_r12(%rdi), %r12
> > + movq TDX_HYPERCALL_r13(%rdi), %r13
> > + movq TDX_HYPERCALL_r14(%rdi), %r14
> > + movq TDX_HYPERCALL_r15(%rdi), %r15
> > +
> > + movl $TDVMCALL_EXPOSE_REGS_MASK, %ecx
> > +
> > + tdcall
> > +
> > + /* TDVMCALL leaf return code is in R10 */
> > + movq %r10, %rax
> > +
> > + /* Copy hypercall result registers to arg struct if needed */
> > + testq $TDX_HCALL_HAS_OUTPUT, %rsi
> > + jz .Lout
> > +
> > + movq %r10, TDX_HYPERCALL_r10(%rdi)
> > + movq %r11, TDX_HYPERCALL_r11(%rdi)
> > + movq %r12, TDX_HYPERCALL_r12(%rdi)
> > + movq %r13, TDX_HYPERCALL_r13(%rdi)
> > + movq %r14, TDX_HYPERCALL_r14(%rdi)
> > + movq %r15, TDX_HYPERCALL_r15(%rdi)
> > +.Lout:
> > + /* Restore callee-saved GPRs as mandated by the x86_64 ABI */
> > + pop %r12
> > + pop %r13
> > + pop %r14
> > + pop %r15
> > +
> > + pop %rbp
> > + ret
> > +
> > +/* Disable executable stack */
> > +.section .note.GNU-stack,"",%progbits
> > diff --git a/tools/testing/selftests/kvm/lib/x86/tdx/tdx.c b/tools/testing/selftests/kvm/lib/x86/tdx/tdx.c
> > new file mode 100644
> > index 000000000000..f417ee75bee2
> > --- /dev/null
> > +++ b/tools/testing/selftests/kvm/lib/x86/tdx/tdx.c
> > @@ -0,0 +1,27 @@
> > +// SPDX-License-Identifier: GPL-2.0-only
> > +
> > +#include "tdx/tdcall.h"
> > +#include "tdx/tdx.h"
> > +
> > +uint64_t tdg_vp_vmcall_instruction_io(uint64_t port, uint64_t size,
> > + uint64_t write, uint64_t *data)
> > +{
> > + struct tdx_hypercall_args args = {
> > + .r10 = TDX_HYPERCALL_STANDARD,
> > + .r11 = TDG_VP_VMCALL_INSTRUCTION_IO,
> > + .r12 = size,
> > + .r13 = write,
> > + .r14 = port,
> > + };
> > + uint64_t ret;
> > +
> > + if (write)
> > + args.r15 = *data;
> > +
> > + ret = __tdx_hypercall(&args, write ? 0 : TDX_HCALL_HAS_OUTPUT);
> > +
> > + if (!write)
> > + *data = 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
> > new file mode 100644
> > index 000000000000..7355b213c344
> > --- /dev/null
> > +++ b/tools/testing/selftests/kvm/lib/x86/tdx/test_util.c
> > @@ -0,0 +1,61 @@
> > +// SPDX-License-Identifier: GPL-2.0-only
> > +
> > +#include <stdbool.h>
> > +#include <stdint.h>
> > +#include <stdlib.h>
> > +#include <sys/wait.h>
> > +#include <unistd.h>
> > +
> > +#include "kvm_util.h"
> > +#include "tdx/tdx.h"
> > +#include "tdx/test_util.h"
> > +
> > +int run_in_new_process(void (*func)(void))
> > +{
> > + int wstatus;
> > + pid_t ret;
> > +
> > + if (fork() == 0) {
> > + func();
> > + exit(0);
> > + }
> > + ret = wait(&wstatus);
> > + if (ret == -1)
> > + return -1;
> > +
> > + if (WIFEXITED(wstatus) && WEXITSTATUS(wstatus))
> > + return -1;
> > + else if (WIFSIGNALED(wstatus))
> > + return -1;
> > +
> > + return 0;
> > +}
> > +
> > +bool is_tdx_enabled(void)
> > +{
> > + return !!(kvm_check_cap(KVM_CAP_VM_TYPES) & BIT(KVM_X86_TDX_VM));
> > +}
> > +
> > +void tdx_test_success(void)
> > +{
> > + uint64_t code = 0;
> > +
> > + tdg_vp_vmcall_instruction_io(TDX_TEST_SUCCESS_PORT, TDX_TEST_SUCCESS_SIZE,
> > + PORT_WRITE, &code);
> > +}
> > +
> > +/*
> > + * Assert that tdx_test_success() was called in the guest.
> > + */
> > +void tdx_test_assert_success(struct kvm_vcpu *vcpu)
> > +{
> > + TEST_ASSERT((vcpu->run->exit_reason == KVM_EXIT_IO) &&
> > + (vcpu->run->io.port == TDX_TEST_SUCCESS_PORT) &&
> > + (vcpu->run->io.size == TDX_TEST_SUCCESS_SIZE) &&
> > + (vcpu->run->io.direction == PORT_WRITE),
> > + "Unexpected exit values while waiting for test completion: %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);
> > +}
> > diff --git a/tools/testing/selftests/kvm/x86/tdx_vm_test.c b/tools/testing/selftests/kvm/x86/tdx_vm_test.c
> > new file mode 100644
> > index 000000000000..fdb7c40065a6
> > --- /dev/null
> > +++ b/tools/testing/selftests/kvm/x86/tdx_vm_test.c
> > @@ -0,0 +1,47 @@
> > +// SPDX-License-Identifier: GPL-2.0-only
> > +
> > +#include <signal.h>
> > +
> > +#include "kvm_util.h"
> > +#include "tdx/tdx_util.h"
> > +#include "tdx/test_util.h"
> > +#include "test_util.h"
> > +
> > +static void guest_code_lifecycle(void)
> > +{
> > + tdx_test_success();
> > +}
> > +
> > +static void verify_td_lifecycle(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_code_lifecycle);
> > + td_finalize(vm);
> > +
> > + printf("Verifying TD lifecycle:\n");
> > +
> > + vcpu_run(vcpu);
> > + tdx_test_assert_success(vcpu);
> > +
> > + kvm_vm_free(vm);
> > + printf("\t ... PASSED\n");
> > +}
> > +
> > +int main(int argc, char **argv)
> > +{
> > + ksft_print_header();
> > +
> > + if (!is_tdx_enabled())
> > + ksft_exit_skip("TDX is not supported by the KVM. Exiting.\n");
> > +
> > + ksft_set_plan(1);
> > + ksft_test_result(!run_in_new_process(&verify_td_lifecycle),
> > + "verify_td_lifecycle\n");
> > +
> > + ksft_finished();
> > + return 0;
> > +}
>
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