Re: [PATCH v9 04/19] KVM: selftests: Expose function to allocate guest vCPU stack

On Thu, Aug 21, 2025 at 4:58 PM Ira Weiny ira.weiny@intel.com wrote:

Sagi Shahar wrote:

[snip]

...

diff --git a/tools/testing/selftests/kvm/lib/x86/processor.c b/tools/testing/selftests/kvm/lib/x86/processor.c index b2a4b11ac8c0..1eae92957456 100644 --- a/tools/testing/selftests/kvm/lib/x86/processor.c +++ b/tools/testing/selftests/kvm/lib/x86/processor.c @@ -687,12 +687,9 @@ void vcpu_arch_set_entry_point(struct kvm_vcpu *vcpu, void *guest_code) vcpu_regs_set(vcpu, &regs); }

-struct kvm_vcpu *vm_arch_vcpu_add(struct kvm_vm *vm, uint32_t vcpu_id) +vm_vaddr_t kvm_allocate_vcpu_stack(struct kvm_vm *vm) {

• struct kvm_mp_state mp_state;
  

• struct kvm_regs regs;
  vm_vaddr_t stack_vaddr;
  

• struct kvm_vcpu *vcpu;
  
  stack_vaddr = __vm_vaddr_alloc(vm, DEFAULT_STACK_PGS * getpagesize(),
                                 DEFAULT_GUEST_STACK_VADDR_MIN,
  

@@ -713,6 +710,15 @@ struct kvm_vcpu *vm_arch_vcpu_add(struct kvm_vm *vm, uint32_t vcpu_id) "__vm_vaddr_alloc() did not provide a page-aligned address"); stack_vaddr -= 8;

• return stack_vaddr;
  

+}

+struct kvm_vcpu *vm_arch_vcpu_add(struct kvm_vm *vm, uint32_t vcpu_id) +{

• struct kvm_mp_state mp_state;
  

• struct kvm_regs regs;
  

• struct kvm_vcpu *vcpu;
  

• vcpu = __vm_vcpu_add(vm, vcpu_id);
  vcpu_init_cpuid(vcpu, kvm_get_supported_cpuid());
  vcpu_init_sregs(vm, vcpu);
  

@@ -721,7 +727,8 @@ struct kvm_vcpu *vm_arch_vcpu_add(struct kvm_vm *vm, uint32_t vcpu_id) /* Setup guest general purpose registers */ vcpu_regs_get(vcpu, &regs); regs.rflags = regs.rflags | 0x2;

• regs.rsp = stack_vaddr;
  

• if (vm->type != KVM_X86_TDX_VM)
  

•         regs.rsp = kvm_allocate_vcpu_stack(vm);
  

At this point in the series vm->type can't be KVM_X86_TDX_VM correct?

So that makes this safe during bisect?

I double checked and no one is creating VMs with KVM_X86_TDX_VM. The first test that sets KVM_X86_TDX_VM is the last patch in the series.

Ira

...

  vcpu_regs_set(vcpu, &regs);

  /* Setup the MP state */

-- 2.51.0.rc1.193.gad69d77794-goog