On Fri, Jun 18, 2021 at 09:09:17AM -0500, Tom Lendacky wrote: > > swiotlb_init_with_tbl uses memblock_alloc to allocate the io_tlb_mem > > and memblock_alloc[1] will do memset in memblock_alloc_try_nid[2], so > > swiotlb_init_with_tbl is also good. > > I'm happy to add the memset in swiotlb_init_io_tlb_mem if you think > > it's clearer and safer. > > On x86, if the memset is done before set_memory_decrypted() and memory > encryption is active, then the memory will look like ciphertext afterwards > and not be zeroes. If zeroed memory is required, then a memset must be > done after the set_memory_decrypted() calls. Which should be fine - we don't care that the memory is cleared to 0, just that it doesn't leak other data. Maybe a comment would be useful, though,
