Re: [PATCH v14 12/22] KVM: selftests: Require guest_memfd for TDX VMs

[Binbin Wu]

On 7/23/2026 7:13 AM, Lisa Wang wrote:
> Force guest_memfd for TDX VMs.
> 
> KVM supports guest_memfd for TDX private memory. Without in-place
> conversion supports, all pages default attributes are private. Thus,
> set page to "shared" for shared pages.
> 
> Signed-off-by: Lisa Wang <wyihan@xxxxxxxxxx>

Reviewed-by: Binbin Wu <binbin.wu@xxxxxxxxxxxxxxx>

One nit below.

> ---
>  tools/testing/selftests/kvm/lib/kvm_util.c     | 2 +-
>  tools/testing/selftests/kvm/lib/ucall_common.c | 8 ++++++++
>  2 files changed, 9 insertions(+), 1 deletion(-)
> 
> diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
> index 0b9d2d383bfa..4a48c4b42095 100644
> --- a/tools/testing/selftests/kvm/lib/kvm_util.c
> +++ b/tools/testing/selftests/kvm/lib/kvm_util.c
> @@ -472,7 +472,7 @@ void kvm_set_files_rlimit(u32 nr_vcpus)
>  static bool is_guest_memfd_required(struct vm_shape shape)
>  {
>  #ifdef __x86_64__
> -	return shape.type == KVM_X86_SNP_VM;
> +	return (shape.type == KVM_X86_SNP_VM || shape.type == KVM_X86_TDX_VM);

Nit:
The parentheses can be dropped.

>  #else
>  	return false;
>  #endif
> diff --git a/tools/testing/selftests/kvm/lib/ucall_common.c b/tools/testing/selftests/kvm/lib/ucall_common.c
> index 029ce21f9f2f..c03dfc763172 100644
> --- a/tools/testing/selftests/kvm/lib/ucall_common.c
> +++ b/tools/testing/selftests/kvm/lib/ucall_common.c
> @@ -27,6 +27,7 @@ static struct ucall_header *ucall_pool;
>  
>  void ucall_init(struct kvm_vm *vm, gpa_t mmio_gpa)
>  {
> +	struct userspace_mem_region *region;
>  	struct ucall_header *hdr;
>  	struct ucall *uc;
>  	gva_t gva;
> @@ -37,6 +38,13 @@ void ucall_init(struct kvm_vm *vm, gpa_t mmio_gpa)
>  	hdr = (struct ucall_header *)addr_gva2hva(vm, gva);
>  	memset(hdr, 0, sizeof(*hdr));
>  
> +	region = vm_get_mem_region(vm, MEM_REGION_DATA);
> +	if (region->region.flags & KVM_MEM_GUEST_MEMFD) {
> +		size_t aligned_sz = align_up(sizeof(*hdr), vm->page_size);
> +
> +		vm_mem_set_shared(vm, addr_gva2gpa(vm, gva), aligned_sz);
> +	}
> +
>  	for (i = 0; i < KVM_MAX_VCPUS; ++i) {
>  		uc = &hdr->ucalls[i];
>  		uc->hva = uc;
>