Re: [PATCH v12 18/23] KVM: selftests: Set entry point for TDX guest code

Reinette Chatre
2025-10-31T16:04:04Z

Hi Sagi,

On 10/28/25 2:20 PM, Sagi Shahar wrote:
> Since the rip register is inaccessible for TDX VMs, we need a different
> way to set the guest entry point for TDX VMs. This is done by writing
> the guest code address to a predefined location in the guest memory and
> loading it into rip as part of the TDX boot code.

Check the changelog for code impersonation, imperative tone, and matching the
KVM requirements.

>
> Signed-off-by: Sagi Shahar <sagis@google.com>
> ---
> tools/testing/selftests/kvm/lib/x86/processor.c | 10 +++++++---
> 1 file changed, 7 insertions(+), 3 deletions(-)
>
> diff --git a/tools/testing/selftests/kvm/lib/x86/processor.c b/tools/testing/selftests/kvm/lib/x86/processor.c
> index 036875fe140f..17f5a381fe43 100644
> --- a/tools/testing/selftests/kvm/lib/x86/processor.c
> +++ b/tools/testing/selftests/kvm/lib/x86/processor.c
> @@ -691,9 +691,13 @@ void vcpu_arch_set_entry_point(struct kvm_vcpu *vcpu, void *guest_code)
> {
> struct kvm_regs regs;
>
> - vcpu_regs_get(vcpu, &regs);
> - regs.rip = (unsigned long) guest_code;
> - vcpu_regs_set(vcpu, &regs);
> + if (is_tdx_vm(vcpu->vm))
> + vm_tdx_set_vcpu_entry_point(vcpu, guest_code);

Please use braces around both branches. (for reference
"Placing Braces and Spaces" in Documentation/process/coding-style.rst)

> + else {
> + vcpu_regs_get(vcpu, &regs);
> + regs.rip = (unsigned long) guest_code;

You can drop the space after the cast above.

> + vcpu_regs_set(vcpu, &regs);
> + }
> }
>
> vm_vaddr_t kvm_allocate_vcpu_stack(struct kvm_vm *vm)

Reinette