[PATCH v13 15/22] KVM: selftests: Call KVM_TDX_INIT_VCPU when creating a new TDX vcpu

From: Lisa Wang

Date: Thu May 21 2026 - 19:20:42 EST


From: Sagi Shahar <sagis@xxxxxxxxxx>

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@xxxxxxxxxx>
Signed-off-by: Lisa Wang <wyihan@xxxxxxxxxx>
---
.../selftests/kvm/include/x86/tdx/tdx_util.h | 24 ++++++++++++++++
tools/testing/selftests/kvm/lib/x86/processor.c | 33 ++++++++++++++++------
2 files changed, 49 insertions(+), 8 deletions(-)

diff --git a/tools/testing/selftests/kvm/include/x86/tdx/tdx_util.h b/tools/testing/selftests/kvm/include/x86/tdx/tdx_util.h
index 9660ea9d2f31..4d01f806b37d 100644
--- a/tools/testing/selftests/kvm/include/x86/tdx/tdx_util.h
+++ b/tools/testing/selftests/kvm/include/x86/tdx/tdx_util.h
@@ -39,6 +39,30 @@ static inline bool is_tdx_vm(struct kvm_vm *vm)
__TEST_ASSERT_VM_VCPU_IOCTL(!ret, #cmd, ret, vm); \
})

+#define __tdx_vcpu_ioctl(vcpu, cmd, _flags, arg) \
+({ \
+ int r; \
+ \
+ union { \
+ struct kvm_tdx_cmd c; \
+ unsigned long raw; \
+ } tdx_cmd = { .c = { \
+ .id = (cmd), \
+ .flags = (u32)(_flags), \
+ .data = (u64)(arg), \
+ } }; \
+ \
+ r = __vcpu_ioctl(vcpu, KVM_MEMORY_ENCRYPT_OP, &tdx_cmd.raw); \
+ r ?: tdx_cmd.c.hw_error; \
+})
+
+#define tdx_vcpu_ioctl(vcpu, cmd, flags, arg) \
+({ \
+ int ret = __tdx_vcpu_ioctl(vcpu, cmd, flags, arg); \
+ \
+ __TEST_ASSERT_VM_VCPU_IOCTL(!ret, #cmd, ret, (vcpu)->vm); \
+})
+
void tdx_init_vm(struct kvm_vm *vm, u64 attributes);
void tdx_vm_setup_boot_code_region(struct kvm_vm *vm);
void tdx_vm_setup_boot_parameters_region(struct kvm_vm *vm, u32 nr_runnable_vcpus);
diff --git a/tools/testing/selftests/kvm/lib/x86/processor.c b/tools/testing/selftests/kvm/lib/x86/processor.c
index 8b0aa64384a1..757da2295ba0 100644
--- a/tools/testing/selftests/kvm/lib/x86/processor.c
+++ b/tools/testing/selftests/kvm/lib/x86/processor.c
@@ -838,6 +838,17 @@ gva_t kvm_allocate_vcpu_stack(struct kvm_vm *vm)
return stack_gva;
}

+static void tdx_vcpu_init(struct kvm_vm *vm, struct kvm_vcpu *vcpu)
+{
+ struct kvm_cpuid2 *cpuid;
+
+ cpuid = allocate_kvm_cpuid2(MAX_NR_CPUID_ENTRIES);
+ tdx_vcpu_ioctl(vcpu, KVM_TDX_GET_CPUID, 0, cpuid);
+ vcpu_init_cpuid(vcpu, cpuid);
+ free(cpuid);
+ tdx_vcpu_ioctl(vcpu, KVM_TDX_INIT_VCPU, 0, NULL);
+}
+
struct kvm_vcpu *vm_arch_vcpu_add(struct kvm_vm *vm, u32 vcpu_id)
{
struct kvm_mp_state mp_state;
@@ -845,15 +856,21 @@ struct kvm_vcpu *vm_arch_vcpu_add(struct kvm_vm *vm, u32 vcpu_id)
struct kvm_regs regs;

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)) {
+ tdx_vcpu_init(vm, vcpu);
+ } 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;

--
2.54.0.746.g67dd491aae-goog