4 Nov
2021
4 Nov
'21
3:13 p.m.
On 11/4/21 8:04 AM, Jarkko Sakkinen wrote:
Do we also need to deal with truncating the PCMD? (For those watching along at home, there are two things SGX swaps to RAM: the actual page data and also some metadata that ensures page integrity and helps prevent things like rolling back to old versions of swapped pages)
Yes.
This can be achieved by iterating through all of the enclave pages, which share the same shmem page for storing their PCMD's, as the one being faulted back. If none of those pages is swapped, the PCMD page can safely truncated.
I was thinking we could just read the page. If it's all 0's, truncate it.