Re: [PATCH v13 19/22] KVM: selftests: Finalize TD memory as part of kvm_arch_vm_finalize_vcpus

[Ackerley Tng]

Lisa Wang <wyihan@xxxxxxxxxx> writes:

> From: Sagi Shahar <sagis@xxxxxxxxxx>
>
> Finalize TDX VM after creation to make it runnable.
>
> Signed-off-by: Sagi Shahar <sagis@xxxxxxxxxx>
> Reviewed-by: Ira Weiny <ira.weiny@xxxxxxxxx>
> Signed-off-by: Lisa Wang <wyihan@xxxxxxxxxx>
> ---
>  tools/testing/selftests/kvm/lib/x86/processor.c | 6 ++++++
>  1 file changed, 6 insertions(+)
>
> diff --git a/tools/testing/selftests/kvm/lib/x86/processor.c b/tools/testing/selftests/kvm/lib/x86/processor.c
> index d84c629a1945..842cac168e99 100644
> --- a/tools/testing/selftests/kvm/lib/x86/processor.c
> +++ b/tools/testing/selftests/kvm/lib/x86/processor.c
> @@ -1479,6 +1479,12 @@ bool kvm_arch_has_default_irqchip(void)
>  	return true;
>  }
>
> +void kvm_arch_vm_finalize_vcpus(struct kvm_vm *vm)
> +{
> +	if (is_tdx_vm(vm))
> +		tdx_vm_finalize(vm);
> +}
> +

This doesn't necessarily block this series, we could (re)move this
later: I'm not sure if kvm_arch_vm_finalize_vcpus() is the correct place
to be finalizing the VM.

Was kvm_arch_vm_finalize_vcpus() supposed to be for finalizing vCPUs
instead?

The awkward part is that kvm_arch_vm_finalize_vcpus() is called from
__vm_create_with_vcpus().

While building this POC to test conversions [1] I only wanted to create
the vm and vcpus and didn't want to finalize yet, since I still needed
to do more mappings in the guest (and I needed the vm pointer to do
mappings in the guest).

Would calling tdx_vm_finalize() from within vcpu_run(), just once, be
too magical?

It's also possible to have some kvm_vm_finalize() call that can be
explicitly and manually invoked from selftests just for CoCo selftests.

[1] https://lore.kernel.org/all/20260605134153.204152-1-ackerleytng@xxxxxxxxxx/

>  void setup_smram(struct kvm_vm *vm, struct kvm_vcpu *vcpu, u64 smram_gpa,
>  		 const void *smi_handler, size_t handler_size)
>  {
>
> --
> 2.54.0.746.g67dd491aae-goog