Re: [PATCH v8 08/30] KVM: selftests: TDX: Update load_td_memory_region() for VM memory backed by guest memfd

On 8/12/2025 4:31 AM, Sean Christopherson wrote:

On Thu, Aug 07, 2025, Sagi Shahar wrote:

[...]

...

• /*
  • TD creation/setup/finalization
  */

@@ -459,28 +474,35 @@ static void load_td_memory_region(struct kvm_vm *vm, if (!sparsebit_any_set(pages)) return;

• if (region->region.guest_memfd != -1)

• register_encrypted_memory_region(vm, region);
  

• sparsebit_for_each_set_range(pages, i, j) { const uint64_t size_to_load = (j - i + 1) * vm->page_size; const uint64_t offset = (i - lowest_page_in_region) * vm->page_size; const uint64_t hva = hva_base + offset; const uint64_t gpa = gpa_base + offset;

• void *source_addr;
  

• void *source_addr = (void *)hva;
  

/* * KVM_TDX_INIT_MEM_REGION ioctl cannot encrypt memory in place. * Make a copy if there's only one backing memory source. */

• source_addr = mmap(NULL, size_to_load, PROT_READ | PROT_WRITE,
  

• 		   MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
  

• TEST_ASSERT(source_addr,
  

• 	    "Could not allocate memory for loading memory region");
  

• memcpy(source_addr, (void *)hva, size_to_load);
  

• if (region->region.guest_memfd == -1) {
  

Oh, here's the "if".

Is it still possible for "region->region.guest_memfd == -1" case? KVM_TDX_INIT_MEM_REGION can only work with guest memfd, right?

...

• 	source_addr = mmap(NULL, size_to_load, PROT_READ | PROT_WRITE,
  

• 			   MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
  

• 	TEST_ASSERT(source_addr,
  

• 		    "Could not allocate memory for loading memory region");
  

• 	memcpy(source_addr, (void *)hva, size_to_load);
  

• 	memset((void *)hva, 0, size_to_load);
  

• }
  

tdx_init_mem_region(vm, source_addr, gpa, size_to_load);

• munmap(source_addr, size_to_load);
  

• if (region->region.guest_memfd == -1)
  

• 	munmap(source_addr, size_to_load);
  

  } }

2.51.0.rc0.155.g4a0f42376b-goog