commit c8f1b3052ca1a6dcebe4e0b8a480e20d8dbf79af
author Jonathan Bailey <jonathanbailey@google.com> Wed Jan 27 01:24:21 2021 +0000
committer CQ Bot <commit-bot@chromium.org> Wed Jan 27 01:24:21 2021 +0000
tree 6b06637f172f63f59feee9d46e4bb1c4739ee492
parent ccaac1ca4cf5c6f992dceef7530bb5dbd915ecd7

[optee] Remove workaround for misbehaving TAs

Previously we synchronized the whole shared memory buffer back to the
VMO even though that should be unnecessary. With this change only the
output range specified by the TA will be written to the client's VMO.

Bug: 35763

Test: optee_smoke_test
      optee-client-test
      optee-controller-test
      optee-message-test
      manual verification of some TA workloads

Change-Id: I96837662d98c38d6d549d9ba5019a6d9f3b88270
Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/475282
Reviewed-by: RJ Ascani <rjascani@google.com>
Commit-Queue: Jonathan Bailey <jonathanbailey@google.com>

src/devices/tee/drivers/optee/optee-message.cc

diff --git a/src/devices/tee/drivers/optee/optee-message.cc b/src/devices/tee/drivers/optee/optee-message.cc
index f926154..117704e 100644
--- a/src/devices/tee/drivers/optee/optee-message.cc
+++ b/src/devices/tee/drivers/optee/optee-message.cc
@@ -352,10 +352,7 @@
   if (actual_size > size_) {
     return ZX_OK;
   }
-  // TODO(fxbug.dev/35763): synchronize only actual_size bytes.
-  // Currently we synchronize the whole shared memory back to the vmo
-  // as a workaround, even though that should be unnecessary.
-  return vmo_.write(reinterpret_cast<void*>(shared_memory_->vaddr()), vmo_offset_, size_);
+  return vmo_.write(reinterpret_cast<void*>(shared_memory_->vaddr()), vmo_offset_, actual_size);
 }
 
 zx_handle_t Message::TemporarySharedMemory::ReleaseVmo() { return vmo_.release(); }