How To Disable Dma On Pld Apr 2026

Hardening Your System: How to Disable DMA on a PLD-Based PCIe Device

This requires an internal TLP filter in your PLD logic: how to disable dma on pld

April 17, 2026 Category: Security & Firmware Hardening Your System: How to Disable DMA on

Direct Memory Access (DMA) is a powerful feature. It allows hardware devices to read/write system RAM without bothering the CPU. However, from a security perspective, an unrestricted DMA channel is a gaping hole—it’s the primary vector for DMA attacks like Thunderclap and FireWire DMA . If you are using a Programmable Logic Device

-- Original DMA request dma_request <= pcie_rx_buffer_full; -- Disabled DMA (hardcoded off) dma_request <= '0'; If you cannot remove the DMA engine, starve it. Program your PLD's Base Address Registers (BARs) to map to a tiny memory region (e.g., 4KB). Configure the PLD to reject any Memory Write or Read TLP (Transaction Layer Packet) that targets an address outside a specific, non-RAM range.

If you are using a Programmable Logic Device (PLD)—such as an FPGA or CPLD—as a PCIe endpoint, disabling DMA isn't always as simple as flipping a driver switch. You have to kill it at the hardware configuration level.