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

[Xiaoyao Li]

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 <wyi...@google.com>
---
  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);

Instead of updating is_guest_memfd_required(), I'm thinking how about 
just replacing is_guest_memfd_required() with 
vm_arch_has_protected_memory()?

  #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);
+       }

this diff about the ucall needs to be a separate patch. What's the 
reason to add it to this patch in this version?

        for (i = 0; i < KVM_MAX_VCPUS; ++i) {
                uc = &hdr->ucalls[i];
                uc->hva = uc;