Intel IOMMU on Linux kernel

最新推荐文章于 2025-06-29 12:08:56 发布

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最新推荐文章于 2025-06-29 12:08:56 发布 · 3.8k 阅读

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#linux #structure #access #domain #translation #generation

本文介绍了Linux内核中Intel IOMMU的支持情况，包括DMAR（DMA重映射）、DRHD（DMA引擎报告结构）、RMRR（预留内存区域报告结构）等关键概念。内容涵盖了IO虚拟地址（IOVA）的生成、图形设备问题的处理以及故障报告机制。通过ACPI枚举平台上的DMA引擎和设备范围，解释了如何为不同设备设置DMA翻译。

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Linux IOMMU Support
===================

The architecture spec can be obtained from the below location.

http://www.intel.com/technology/virtualization/

This guide gives a quick cheat sheet for some basic understanding.

Some Keywords

DMAR - DMA remapping
DRHD - DMA Engine Reporting Structure
RMRR - Reserved memory Region Reporting Structure
ZLR - Zero length reads from PCI devices
IOVA - IO Virtual address.

Basic stuff
-----------

ACPI enumerates and lists the different DMA engines in the platform, and
device scope relationships between PCI devices and which DMA engine controls
them.

What is RMRR?
-------------

There are some devices the BIOS controls, for e.g USB devices to perform
PS2 emulation. The regions of memory used for these devices are marked
reserved in the e820 map. When we turn on DMA translation, DMA to those
regions will fail. Hence B