Intel 64 and IA-32 Architectures Software Developers Manual Volume 3B, System Programming Guide Part 2
Table Of Contents
- Chapter 18 Debugging and Performance Monitoring
- 18.1 Overview of Debug Support Facilities
- 18.2 Debug Registers
- 18.3 Debug Exceptions
- 18.4 Last Branch Recording Overview
- 18.5 Last Branch, Interrupt, and Exception Recording (Intel® Core™2 Duo and Intel® Atom™ Processor Family)
- 18.6 Last Branch, Interrupt, and Exception Recording (Intel® Core™i7 Processor Family)
- 18.7 Last Branch, Interrupt, and Exception Recording (Processors based on Intel NetBurst® Microarchitecture)
- 18.7.1 CPL-Qualified Branch Trace Mechanism
- 18.7.2 MSR_DEBUGCTLA MSR
- 18.7.3 LBR Stack for Processors Based on Intel NetBurst Microarchitecture
- 18.7.4 Monitoring Branches, Exceptions, and Interrupts
- 18.7.5 Single-Stepping on Branches, Exceptions, and Interrupts
- 18.7.6 Branch Trace Messages
- 18.7.7 Last Exception Records
- 18.7.8 Branch Trace Store (BTS)
- 18.8 Last Branch, Interrupt, and Exception Recording (Intel® Core™ Solo and Intel® Core™ Duo Processors)
- 18.9 Last Branch, Interrupt, and Exception Recording (Pentium M Processors)
- 18.10 Last Branch, Interrupt, and Exception Recording (P6 Family Processors)
- 18.11 Time-Stamp Counter
- 18.12 Performance Monitoring Overview
- 18.13 Architectural Performance Monitoring
- 18.14 Performance Monitoring (Intel® Core™ Solo and Intel® Core™ Duo Processors)
- 18.15 Performance Monitoring (Processors based on Intel® Core™ Microarchitecture)
- 18.16 Performance Monitoring (Processors based on Intel® Atom™ Microarchitecture)
- 18.17 Performance Monitoring for Processors based on Intel® Microarchitecture (Nehalem)
- 18.18 Performance Monitoring (Processors Based on Intel NetBurst microarchitecture)
- 18.18.1 ESCR MSRs
- 18.18.2 Performance Counters
- 18.18.3 CCCR MSRs
- 18.18.4 Debug Store (DS) Mechanism
- 18.18.5 DS Save Area
- 18.18.6 Programming the Performance Counters for Non-Retirement Events
- 18.18.6.1 Selecting Events to Count
- 18.18.6.2 Filtering Events
- 18.18.6.3 Starting Event Counting
- 18.18.6.4 Reading a Performance Counter’s Count
- 18.18.6.5 Halting Event Counting
- 18.18.6.6 Cascading Counters
- 18.18.6.7 EXTENDED CASCADING
- 18.18.6.8 Generating an Interrupt on Overflow
- 18.18.6.9 Counter Usage Guideline
- 18.18.7 At-Retirement Counting
- 18.18.8 Precise Event-Based Sampling (PEBS)
- 18.18.9 Operating System Implications
- 18.19 Performance Monitoring and Intel Hyper- Threading Technology in Processors Based on Intel NetBurst Microarchitecture
- 18.20 Counting Clocks
- 18.21 Performance Monitoring, Branch Profiling and System Events
- 18.22 Performance Monitoring and Dual-Core Technology
- 18.23 Performance Monitoring on 64-bit Intel Xeon Processor MP with Up to 8-MByte L3 Cache
- 18.24 Performance Monitoring on L3 and Caching Bus Controller sub-systems
- 18.25 Performance Monitoring (P6 Family Processor)
- 18.26 Performance Monitoring (Pentium Processors)
- Chapter 19 Introduction to Virtual-Machine Extensions
- Chapter 20 Virtual-Machine Control Structures
- 20.1 Overview
- 20.2 Format of the VMCS Region
- 20.3 Organization of VMCS Data
- 20.4 Guest-State Area
- 20.5 Host-State Area
- 20.6 VM-Execution Control Fields
- 20.6.1 Pin-Based VM-Execution Controls
- 20.6.2 Processor-Based VM-Execution Controls
- 20.6.3 Exception Bitmap
- 20.6.4 I/O-Bitmap Addresses
- 20.6.5 Time-Stamp Counter Offset
- 20.6.6 Guest/Host Masks and Read Shadows for CR0 and CR4
- 20.6.7 CR3-Target Controls
- 20.6.8 Controls for APIC Accesses
- 20.6.9 MSR-Bitmap Address
- 20.6.10 Executive-VMCS Pointer
- 20.6.11 Extended-Page-Table Pointer (EPTP)
- 20.6.12 Virtual-Processor Identifier (VPID)
- 20.7 VM-Exit Control Fields
- 20.8 VM-Entry Control Fields
- 20.9 VM-Exit Information Fields
- 20.10 Software Access to the VMCS and Related Structures
- 20.11 Using VMCLEAR to Initialize a VMCS Region
- Chapter 21 VMX Non-Root Operation
- 21.1 Instructions That Cause VM Exits
- 21.2 APIC-Access VM Exits
- 21.3 Other Causes of VM Exits
- 21.4 Changes to Instruction Behavior in VMX Non- Root Operation
- 21.5 APIC Accesses That Do Not Cause VM Exits
- 21.6 Other Changes in VMX Non-Root Operation
- 21.7 Features Specific to VMX Non-Root Operation
- Chapter 22 VM Entries
- 22.1 Basic VM-Entry Checks
- 22.2 Checks on VMX Controls and Host-State Area
- 22.3 Checking and Loading Guest State
- 22.3.1 Checks on the Guest State Area
- 22.3.1.1 Checks on Guest Control Registers, Debug Registers, and MSRs
- 22.3.1.2 Checks on Guest Segment Registers
- 22.3.1.3 Checks on Guest Descriptor-Table Registers
- 22.3.1.4 Checks on Guest RIP and RFLAGS
- 22.3.1.5 Checks on Guest Non-Register State
- 22.3.1.6 Checks on Guest Page-Directory-Pointer-Table Entries
- 22.3.2 Loading Guest State
- 22.3.3 Clearing Address-Range Monitoring
- 22.3.1 Checks on the Guest State Area
- 22.4 Loading MSRs
- 22.5 Event Injection
- 22.6 Special Features of VM Entry
- 22.6.1 Interruptibility State
- 22.6.2 Activity State
- 22.6.3 Delivery of Pending Debug Exceptions after VM Entry
- 22.6.4 VMX-Preemption Timer
- 22.6.5 Interrupt-Window Exiting
- 22.6.6 NMI-Window Exiting
- 22.6.7 VM Exits Induced by the TPR Shadow
- 22.6.8 Pending MTF VM Exits
- 22.6.9 VM Entries and Advanced Debugging Features
- 22.7 VM-Entry Failures During or After Loading Guest State
- 22.8 Machine Checks During VM Entry
- Chapter 23 VM Exits
- 23.1 Architectural State Before a VM Exit
- 23.2 Recording VM-Exit Information and Updating VM-Entry Control Fields
- 23.3 Saving Guest State
- 23.4 Saving MSRs
- 23.5 Loading Host State
- 23.5.1 Loading Host Control Registers, Debug Registers, MSRs
- 23.5.2 Loading Host Segment and Descriptor-Table Registers
- 23.5.3 Loading Host RIP, RSP, and RFLAGS
- 23.5.4 Checking and Loading Host Page-Directory-Pointer-Table Entries
- 23.5.5 Updating Non-Register State
- 23.5.6 Clearing Address-Range Monitoring
- 23.6 Loading MSRs
- 23.7 VMX Aborts
- 23.8 Machine Check During VM Exit
- Chapter 24 Support for Address Translation
- 24.1 Virtual Processor Identifiers (VPIDs)
- 24.2 Extended Page Tables (EPT)
- 24.3 Caching Translation Information
- Chapter 25 System Management
- 25.1 System Management Mode Overview
- 25.2 System Management Interrupt (SMI)
- 25.3 Switching Between SMM and the Other Processor Operating Modes
- 25.4 SMRAM
- 25.5 SMI Handler Execution Environment
- 25.6 Exceptions and Interrupts Within SMM
- 25.7 Managing Synchronous and Asynchronous System Management Interrupts
- 25.8 NMI Handling While in SMM
- 25.9 SMM Revision Identifier
- 25.10 Auto HALT Restart
- 25.11 SMBASE Relocation
- 25.12 I/O Instruction Restart
- 25.13 SMM Multiple-Processor Considerations
- 25.14 Default Treatment of SMIs and SMM with VMX Operation and SMX Operation
- 25.15 Dual-Monitor Treatment of SMIs and SMM
- 25.15.1 Dual-Monitor Treatment Overview
- 25.15.2 SMM VM Exits
- 25.15.3 Operation of an SMM Monitor
- 25.15.4 VM Entries that Return from SMM
- 25.15.4.1 Checks on the Executive-VMCS Pointer Field
- 25.15.4.2 Checks on VM-Execution Control Fields
- 25.15.4.3 Checks on VM-Entry Control Fields
- 25.15.4.4 Checks on Guest Non-Register State
- 25.15.4.5 Loading Guest State
- 25.15.4.6 VMX-Preemption Timer
- 25.15.4.7 Updating the Current-VMCS and SMM-Transfer VMCS Pointers
- 25.15.4.8 VM Exits Induced by VM Entry
- 25.15.4.9 SMI Blocking
- 25.15.4.10 Failures of VM Entries That Return from SMM
- 25.15.5 Enabling the Dual-Monitor Treatment
- 25.15.6 Activating the Dual-Monitor Treatment
- 25.15.7 Deactivating the Dual-Monitor Treatment
- 25.16 SMI and Processor Extended State Management
- Chapter 26 Virtual-Machine Monitor Programming Considerations
- 26.1 VMX System Programming Overview
- 26.2 Supporting Processor Operating Modes in Guest Environments
- 26.3 Managing VMCS Regions and Pointers
- 26.4 Using VMX Instructions
- 26.5 VMM Setup & Tear Down
- 26.6 Preparation and Launching a Virtual Machine
- 26.7 Handling of VM Exits
- 26.8 Multi-Processor Considerations
- 26.9 32-Bit and 64-Bit Guest Environments
- 26.10 Handling Model Specific Registers
- 26.11 Handling Accesses to Control Registers
- 26.12 Performance Considerations
- Chapter 27 Virtualization of System Resources
- 27.1 Overview
- 27.2 Virtualization Support for Debugging Facilities
- 27.3 Memory Virtualization
- 27.4 Microcode Update Facility
- Chapter 28 Handling Boundary Conditions in a Virtual Machine Monitor
- Appendix A Performance-Monitoring Events
- A.1 Architectural Performance-Monitoring Events
- A.2 Performance Monitoring Events for Intel® Intel® Core™i7 Processor Family
- A.3 Performance Monitoring Events for Intel® Xeon® Processor 5200, 5400 Series and Intel® Core™2 Extreme ProcessorS QX 9000 Series
- A.4 Performance Monitoring Events for Intel® Xeon® Processor 3000, 3200, 5100, 5300 Series and Intel® Core™2 Duo ProcessorS
- A.5 Performance Monitoring Events for Intel® Atom™ ProcessorS
- A.6 Performance Monitoring Events for Intel® Core™ Solo and Intel® Core™ Duo ProcessorS
- A.7 Pentium 4 and Intel Xeon Processor Performance-Monitoring Events
- A.8 Performance Monitoring Events for Intel® Pentium® M ProcessorS
- A.9 P6 Family Processor Performance- Monitoring Events
- A.10 Pentium Processor Performance- Monitoring Events
- Appendix B Model-Specific Registers (MSRs)
- B.1 Architectural MSRs
- B.2 MSRs In the Intel® Core™ 2 Processor Family
- B.3 MSRs In the Intel® Atom™ Processor Family
- B.4 MSRs In the Intel® Microarchitecture (Nehalem)
- B.5 MSRs In the Pentium® 4 and Intel® Xeon® Processors
- B.6 MSRs In Intel® Core™ Solo and Intel® Core™ Duo Processors
- B.7 MSRs In the Pentium M Processor
- B.8 MSRs In the P6 Family Processors
- B.9 MSRs in Pentium Processors
- Appendix C MP Initialization For P6 Family Processors
- Appendix D Programming the LINT0 and LINT1 Inputs
- Appendix E Interpreting Machine-Check Error Codes
- E.1 Incremental Decoding Information: Processor Family 06H Machine Error Codes For Machine Check
- E.2 Incremental Decoding Information: Intel Core 2 Processor Family Machine Error Codes For Machine Check
- E.3 Incremental Decoding Information: Processor Family with CPUID DisplayFamily_DisplayModel Signature 06_1AH, Machine Error Codes For Machine Check
- E.4 Incremental Decoding Information: Processor Family 0FH Machine Error Codes For Machine Check
- Appendix F APIC Bus Message Formats
- Appendix G VMX Capability Reporting Facility
- Appendix H Field Encoding in VMCS
- Appendix I VMX Basic Exit Reasons

23-36 Vol. 3
VM EXITS
23.5.3 Loading Host RIP, RSP, and RFLAGS
RIP and RSP are loaded from the RIP field and the RSP field, respectively. RFLAGS is
cleared, except bit 1, which is always set.
23.5.4 Checking and Loading Host Page-Directory-Pointer-Table
Entries
If CR0.PG = 1 and CR4.PAE = 1, the logical processor uses the physical-address
extension (PAE). If, in addition, IA32_EFER.LMA = 0, the logical processor uses
PAE paging. See Section 3.8 of the Intel® 64 and IA-32 Architectures Software
Developer’s Manual, Volume 3A.
1
When in PAE paging is in use, the physical address
in CR3 references a table of page-directory-pointer-table entries (PDPTEs). A
MOV to CR3 when PAE paging is in use checks the validity of the PDPTEs and, if they
are valid, loads them into the processor (into internal, non-architectural registers).
A VM exit is to a VMM that uses PAE paging if (1) bit 5 (corresponding to CR4.PAE) is
set in the CR4 field in the host-state area of the VMCS; and (2) the “host address-
space size” VM-exit control is 0. Such a VM exit may check the validity of the PDPTEs
referenced by the CR3 field in the host-state area of the VMCS. Such a VM exit must
check their validity if either (1) PAE paging was not in use before the VM exit; or
(2) the value of CR3 is changing as a result of the VM exit. A VM exit to a VMM that
does not use PAE paging must not check the validity of the PDPTEs.
A VM exit that checks the validity of the PDPTEs uses the same checks that are used
when CR3 is loaded with MOV to CR3 when PAE paging is in use. If MOV to CR3 would
cause a general-protection exception due to the PDPTEs that would be loaded (e.g.,
because a reserved bit is set), a VMX abort occurs (see Section 23.7). If a VM exit to
a VMM that uses PAE does not cause a VMX abort, the PDPTEs are loaded into the
processor as would MOV to CR3, using the value of CR3 being load by the VM exit.
23.5.5 Updating Non-Register State
VM exits affect the non-register state of a logical processor as follows:
• A logical processor is always in the active state after a VM exit.
• Event blocking is affected as follows:
— There is no blocking by STI or by MOV SS after a VM exit.
— VM exits caused directly by non-maskable interrupts (NMIs) cause blocking
by NMI (see Table 20-3). Other VM exits do not affect blocking by NMI. (See
Section 23.1 for the case in which an NMI causes a VM exit indirectly.)
1. On processors that support Intel 64 architecture, the physical-address extension may support
more than 36 physical-address bits. Software can determine a processor’s physical-address
width by executing CPUID with 80000008H in EAX. The physical-address width is returned in
bits 7:0 of EAX.