Re: [PATCH v12 17/23] KVM: selftests: Call KVM_TDX_INIT_VCPU when creating a new TDX vcpu

On 10/29/2025 5:20 AM, Sagi Shahar wrote:

TDX VMs need to issue the KVM_TDX_INIT_VCPU ioctl for each vcpu after vcpu creation.

Since the cpuids for TD are managed by the TDX module, read the values virtualized for the TD using KVM_TDX_GET_CPUID and set them in kvm using KVM_SET_CPUID2 so that kvm has an accurate view of the VM cpuid values.

Signed-off-by: Sagi Shahar sagis@google.com

.../testing/selftests/kvm/lib/x86/processor.c | 35 ++++++++++++++----- 1 file changed, 27 insertions(+), 8 deletions(-)

diff --git a/tools/testing/selftests/kvm/lib/x86/processor.c b/tools/testing/selftests/kvm/lib/x86/processor.c index 990f2769c5d8..036875fe140f 100644 --- a/tools/testing/selftests/kvm/lib/x86/processor.c +++ b/tools/testing/selftests/kvm/lib/x86/processor.c @@ -722,6 +722,19 @@ vm_vaddr_t kvm_allocate_vcpu_stack(struct kvm_vm *vm) return stack_vaddr; } +static void vm_tdx_vcpu_add(struct kvm_vm *vm, struct kvm_vcpu *vcpu) +{

• struct kvm_cpuid2 *cpuid;
• cpuid = allocate_kvm_cpuid2(MAX_NR_CPUID_ENTRIES);
• vm_tdx_vcpu_ioctl(vcpu, KVM_TDX_GET_CPUID, 0, cpuid);
• vcpu_init_cpuid(vcpu, cpuid);
• free(cpuid);
• vm_tdx_vcpu_ioctl(vcpu, KVM_TDX_INIT_VCPU, 0, NULL);
• vm_tdx_load_vcpu_boot_parameters(vm, vcpu);

+}

• struct kvm_vcpu *vm_arch_vcpu_add(struct kvm_vm *vm, uint32_t vcpu_id) { struct kvm_mp_state mp_state;

@@ -729,15 +742,21 @@ struct kvm_vcpu *vm_arch_vcpu_add(struct kvm_vm *vm, uint32_t vcpu_id) struct kvm_vcpu *vcpu; vcpu = __vm_vcpu_add(vm, vcpu_id);

• vcpu_init_cpuid(vcpu, kvm_get_supported_cpuid());
• vcpu_init_sregs(vm, vcpu);
• vcpu_init_xcrs(vm, vcpu);

• /* Setup guest general purpose registers */
• vcpu_regs_get(vcpu, &regs);
• regs.rflags = regs.rflags | 0x2;
• regs.rsp = kvm_allocate_vcpu_stack(vm);
• vcpu_regs_set(vcpu, &regs);

• if (is_tdx_vm(vm)) {

• vm_tdx_vcpu_add(vm, vcpu);
  

Nit: Since vcpu is added by  __vm_vcpu_add() above, using 'init' instead of 'add' in the function name makes it more clear.

• } else {

• vcpu_init_cpuid(vcpu, kvm_get_supported_cpuid());
  

• vcpu_init_sregs(vm, vcpu);
  

• vcpu_init_xcrs(vm, vcpu);
  

• /* Setup guest general purpose registers */
  

• vcpu_regs_get(vcpu, &regs);
  

• regs.rflags = regs.rflags | 0x2;
  

• regs.rsp = kvm_allocate_vcpu_stack(vm);
  

• vcpu_regs_set(vcpu, &regs);
  

• }

/* Setup the MP state */ mp_state.mp_state = 0;