Techniques for processing I/O operations may include performing DMA (direct memory access) operations between a data storage system, one or more physical storage devices, and a hardware component that communicate over at least one bus using a DMA-based protocol, such as NVMe (Non-Volatile Memory Express). The hardware device may perform encryption and decryption processing of data that is, respectively, stored to, and read from, physical non-volatile storage. The hardware device may optionally perform other processing for other data-related operations such as any of data validation and integrity checking, data deduplication, data compression, and data decompression. When performing DMA transfers, multiple descriptors, such as SGLs (scatter gather lists) or PRPs (physical region pages), for multiple data portions having logically contiguous consecutive logical addresses may be combined into a single descriptor sent in a single DMA operation.