Symmetric I/O Mode | Intel MultiProcessor instruction

Hardware Specification

3.6.2.3Symmetric I/O Mode

Some MP operating systems operate in Symmetric I/O Mode. This mode requires at least one I/O APIC to operate. In this mode, I/O interrupts are generated by the I/O APIC. All 8259 interrupt lines are either masked or work together with the I/O APIC in a mixed mode. See Figure 3-5 for an overview of Symmetric I/O Mode.

BSP		AP1		AP2
CPU 1		CPU 2		CPU 3

	NMI	INTR		NMI INTR		NMI	INTR
		LOCAL		LOCAL			LOCAL
REG.		APIC		APIC			APIC
REG.		1		2				3
MARK	LINTIN0		LINTIN1	LINTIN0	LINTIN1	LINTIN0		LINTIN1
	LINTIN0		LINTIN1	LINTIN0	LINTIN1	LINTIN0		LINTIN1
LINTIN1
LINTIN0
RESET
ICC BUS
NMI
				8259A-	INTR
				EQUIVALENT
				PICS
INTERRUPT INPUTS								I/O
INTERRUPT INPUTS							APIC
							APIC

SHADED AREAS INDICATE UNUSED CIRCUITS. DOTTED LINE SHOWS INTERRUPT PATH.

Figure 3-5. Symmetric I/O Mode

The APIC I/O unit has general-purpose interrupt inputs that can be individually programmed to different operating modes. The I/O APIC interrupt line assignments are system implementation specific. Refer to Chapter 4 for custom implementations and to Chapter 5 for default configurations.

The hardware must support a mode of operation in which the system can switch easily to Symmetric I/O mode from PIC or Virtual Wire mode. When the operating system is ready to switch to MP operation, it writes a 01H to the IMCR register, if that register is implemented, and enables I/O APIC Redirection Table entries. The hardware must not require any other action on the part of software to make the transition to Symmetric I/O mode.

Version 1.4

3-11

Image 31

Intel MultiProcessor manual Symmetric I/O Mode

Contents

MultiProcessor Specification Copyright 1993-1997. Intel Corporation, All Rights Reserved Revision Revision History Date Revision HistoryPage Table of Contents Default Configurations MP Configuration TableContents Appendix B Operating System Programming Guidelines Appendix a System Bios Programming GuidelinesAppendix E Errata Glossary Tables Figures Examples Page Conceptual Overview Goals MultiProcessor Specification Features of the SpecificationScope Introduction Target AudienceOrganization of This Document Document Organization For More Information Conventions Used in This Document System Overview System Processors Hardware Overview System Overview Advanced Programmable Interrupt Controller 4 I/O Expansion Bus System Memory Operating System Overview Bios OverviewPage System Memory Configuration Hardware Specification System Memory Address Map System Memory Cacheability and Shareability Memory Cacheability Map Hardware Specification Locking External Cache Subsystem Multiprocessor Interrupt Control Posted Memory WriteApic Architecture Apic Versions Interrupt Modes PIC Mode PIC Mode Virtual Wire Mode via Local Apic Virtual Wire Mode Virtual Wire Mode via I/O Apic Symmetric I/O Mode Symmetric I/O Mode Floating Point Exception Interrupt Assignment of System Interrupts to the Apic Local UnitApic Memory Mapping Apic Identification Apic Interval Timers System-wide Reset Reset Support Processor-specific Init System-wide Init System Initial State Support for Fault-resilient Booting MP Configuration Table MultiProcessor Specification MP Floating Pointer Structure MP Configuration TableOffset Length Field Bytesbits in bits Description Information Bytes MP FeatureOffset Length Field Bytesbits Bits Description Information Byte MP Configuration Table Header MP Configuration Table Header MP Configuration Table Header Fields Base MP Configuration Table EntriesOffset Length Field Bytes Bits Description Apic Base MP Configuration Table Entry TypesProcessor Entries Length Entry Description Entry Type Code Bytes Comments Processor Entry Fields Bit Name Description Comments Feature Flags from Cpuid InstructionIntel486 and Pentium Processor Signatures Family Model Stepping a Description String Bus EntriesBUS ID BUS Type Bus Type String Description Bus Type String Values I/O Apic Entry Fields 3 I/O Apic Entries4 I/O Interrupt Assignment Entries Apic Entry I/O Interrupt Entry 10. I/O Interrupt Entry Fields 11. Interrupt Type Values Local Interrupt Assignment EntriesInterrupt Type Description Comments LINTIN# 12. Local Interrupt Entry FieldsDestination Local Apic ID Destination Local Apic Extended MP Configuration Table Entries System Address Space Mapping Entries 14. System Address Space Mapping Entry Fields 10. Example System with Multiple Bus Types and Bridge Types Bus Hierarchy Descriptor Entry Compatibility Bus Address Space Modifier Entry 12. Compatibility Bus Address Space Modifier Entry 16. Compatibility Bus Address Space Modifier Entry Fields Default Configurations Config Code CPUs Type Variant Schematic Discrete Apic ConfigurationsDefault Configurations Default Number Bus Default Configurations Default Configuration for Discrete Apic Integrated Apic Configurations Default Configuration for Integrated Apic First I/O Default Configuration Interrupt AssignmentsConfig INTINx Comments Assignment of I/O Interrupts to the Apic I/O Unit Level-triggered Interrupt Support All Local APICs Config LINTINx CommentsAssignment of System Interrupts to the Apic Local Unit Eisa and IRQ13 MultiProcessor Specification Bios Post Initialization System Bios Programming Guidelines Controlling the Application Processors Programming the Apic for Virtual Wire Mode System Bios Programming Guidelines Example A-1. Programming Local Apic for Virtual Wire Mode NMI Constructing the MP Configuration Table System Bios Programming Guidelines Page Operating System Programming Guidelines Operating System Boot-up Interrupt Mode Initialization and Handling Operating System Booting and Self-configuration Operating System Programming Guidelines Application Processor Startup Using Init IPI AP Shutdown Handling Using Startup IPI Handling TLB Invalidation Other IPI ApplicationsSpurious Apic Interrupts Handling Cache Flush Supporting Unequal Processors Page System Compliance Checklist Page Variable Interrupt Routing Interrupt Routing with Multiple APICs Fixed Interrupt Routing INTD# Bus Entries in Systems with More Than One PCI BusI/O Interrupt Assignment Entries for PCI Devices Multiple I/O Apic Multiple PCI Bus SystemsPage Errata 126 System Address Space Entry System Address Space Mapping Entries Address Base 14. System Address Space Mapping Entry FieldsEntry Length Address Type Space records must also be provided Bus Hierarchy Descriptor Entry Parent BUS BUS Informationsd Glossary Glossary-2 Order Number