[PATCH v6 08/30] KVM: selftests: TDX: Update load_td_memory_region() for VM memory backed by guest memfd

[Sagi Shahar]

From: Ackerley Tng <ackerley...@google.com>

If guest memory is backed by restricted memfd

+ UPM is being used, hence encrypted memory region has to be
  registered
+ Can avoid making a copy of guest memory before getting TDX to
  initialize the memory region

Signed-off-by: Ackerley Tng <ackerley...@google.com>
Signed-off-by: Sagi Shahar <sa...@google.com>
---
 .../selftests/kvm/lib/x86/tdx/tdx_util.c      | 38 +++++++++++++++----
 1 file changed, 30 insertions(+), 8 deletions(-)

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 bb074af4a476..e2bf9766dc03 100644
--- a/tools/testing/selftests/kvm/lib/x86/tdx/tdx_util.c
+++ b/tools/testing/selftests/kvm/lib/x86/tdx/tdx_util.c
@@ -324,6 +324,21 @@ static void tdx_td_finalize_mr(struct kvm_vm *vm)
        tdx_ioctl(vm->fd, KVM_TDX_FINALIZE_VM, 0, NULL);
 }
 
+/*
+ * Other ioctls
+ */
+
+/*
+ * Register a memory region that may contain encrypted data in KVM.
+ */
+static void register_encrypted_memory_region(struct kvm_vm *vm,
+                                            struct userspace_mem_region 
*region)
+{
+       vm_set_memory_attributes(vm, region->region.guest_phys_addr,
+                                region->region.memory_size,
+                                KVM_MEMORY_ATTRIBUTE_PRIVATE);
+}
+
 /*
  * 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) {
+                       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);
        }
 }
 
-- 
2.49.0.504.g3bcea36a83-goog