Re: [PATCH v13 04/22] KVM: selftests: TDX: Use KVM_TDX_CAPABILITIES to validate TDs' attribute configuration

[Xiaoyao Li]

On 5/22/2026 7:16 AM, Lisa Wang wrote:
> From: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
>
> Make sure that all the attributes enabled by the test are reported as
> supported by both the TDX module and KVM. KVM filters out the attributes
> not supported by itself.
>
> This also exercises the KVM_TDX_CAPABILITIES ioctl.
>
> Signed-off-by: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
> Co-developed-by: Sagi Shahar <sagis@xxxxxxxxxx>
> Signed-off-by: Sagi Shahar <sagis@xxxxxxxxxx>
> Reviewed-by: Binbin Wu <binbin.wu@xxxxxxxxxxxxxxx>
> Reviewed-by: Ira Weiny <ira.weiny@xxxxxxxxx>
> Signed-off-by: Lisa Wang <wyihan@xxxxxxxxxx>

Reviewed-by: Xiaoyao Li <xiaoyao.li@xxxxxxxxx>

> ---
>   tools/testing/selftests/kvm/lib/x86/tdx/tdx_util.c | 14 ++++++++++++++
>   1 file changed, 14 insertions(+)
>
> diff --git a/tools/testing/selftests/kvm/lib/x86/tdx/tdx_util.c b/tools/testing/selftests/kvm/lib/x86/tdx/tdx_util.c
> index 868ff62e22f2..e5c998874a0d 100644
> --- a/tools/testing/selftests/kvm/lib/x86/tdx/tdx_util.c
> +++ b/tools/testing/selftests/kvm/lib/x86/tdx/tdx_util.c
> @@ -110,6 +110,18 @@ static void tdx_filter_cpuid(struct kvm_vm *vm,
>   	free(tdx_cap);
>   }
>   
> +static void tdx_check_attributes(struct kvm_vm *vm, u64 attributes)
> +{
> +	struct kvm_tdx_capabilities *tdx_cap;
> +
> +	tdx_cap = tdx_read_capabilities(vm);

well, this is another caller of tdx_read_capabilities().

As I commented in the previous patch, it's worth caching the result in 
tdx_read_capabilities() like what kvm_get_supported_cpuid() does for 
kvm_supported_cpuid.

And it can help only print the debug once.

> +	/* Make sure all the attributes are reported as supported */
> +	TEST_ASSERT_EQ(attributes & tdx_cap->supported_attrs, attributes);
> +
> +	free(tdx_cap);
> +}
> +
>   void tdx_init_vm(struct kvm_vm *vm, u64 attributes)
>   {
>   	struct kvm_tdx_init_vm *init_vm;
> @@ -129,6 +141,8 @@ void tdx_init_vm(struct kvm_vm *vm, u64 attributes)
>   	memcpy(&init_vm->cpuid, cpuid, kvm_cpuid2_size(cpuid->nent));
>   	free(cpuid);
>   
> +	tdx_check_attributes(vm, attributes);
> +
>   	init_vm->attributes = attributes;
>   
>   	tdx_vm_ioctl(vm, KVM_TDX_INIT_VM, 0, init_vm);