CpuIoPei

Index: 0408 | Size: 5,280 bytes | Phase: PEI | Format: PE32 (Ia32)

Overview

CPU I/O PEIM providing the EFI_PEI_CPU_IO_PPI interface for port I/O, MMIO, and memory-mapped I/O access during the PEI phase. Implements byte/word/dword port I/O read/write with string variants, MMIO access (word/dword/qword), and unaligned memory read/write helpers (16/32/64-bit). Validates I/O port alignment and invokes x86 assembly I/O instructions.

Key Functions

• IoReadBufferFx / IoReadPortWordString / IoReadPortDwordString -- Port I/O string read (byte/word/dword)
• IoWriteBufferByte / IoWritePortWordString / IoWritePortDwordString -- Port I/O string write (byte/word/dword)
• IoReadPortWord / IoWritePortWord -- Single port I/O word operations
• IoReadPortDword / IoWritePortDword -- Single port I/O dword operations
• IoReadMmioWord / IoWriteMmioWord / IoReadMmioQword / IoWriteMmioQword -- MMIO read/write
• ReadUnaligned16 / WriteUnaligned16 / ReadUnaligned32 / WriteUnaligned32 / ReadUnaligned64 -- Unaligned memory access with DEBUG asserts
• GetPeiServicesTable -- PEI services table pointer retrieval
• GetDebugInstance -- Debug PPI locator for ASSERT messages
• SetMem / SetMem32 / SetMem32Fill / CopyMem -- Memory utility wrappers

Dependencies

• EFI_PEI_CPU_IO_PPI -- CPU I/O PPI interface
• x86 IN/OUT instruction family (in/out byte/word/dword, string variants)
• MMIO address space
• Debug Library PPI (for unaligned access asserts)

Platform

Intel Purley (Skylake-SP Xeon), HR650X
Source: UefiCpuPkg/CpuIoPei/CpuIoPei.c