1. Microsoft Virtualization Deep Dive
11/11/2018 3:25 PM
Microsoft Virtualization Deep Dive
Current and Future Architecture
Shai Ofek
Principal Technology Architect
Windows Server Division, PMG
© 2006 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION. 1

2. Topics Reviewed Virtualization Characterization
Virtual Server 2005 R2 Architecture
Windows Server Virtualization Architecture

3. Virtualization Characterization
From IBM System Virtualization Engine:
“There are two types of hypervisors”
Type 1 hypervisors run directly on the system hardware
Type 2 hypervisors run on a host operating system that provides virtualization services, such as I/O device support and memory management

4. Type-1 VMM (Hypervisor)
VMM Arrangements
Type-2 VMM
Hybrid VMM
Type-1 VMM (Hypervisor)
Guest 1
Guest 2
VMM
Guest 1
Guest 2
Guest 1
Guest 2
Host OS
Host OS
VMM
VMM
Hardware
Hardware
Hardware
Examples: JVM CLR
Examples: Virtual PC & Virtual Server 2005 R2
Examples: Windows Virtualization
In Production today
In Beta Q4 2006 4

5. Virtual Server R2: Enhancements (1 of 4)
Greater Scalability with 64-bit
x64 hosts – 32-bit guests
Windows Server 2003 Standard x64 Edition
Windows Server 2003 Enterprise x64 Edition
Windows XP Professional x64 Edition
64-bit port of Virtual Machine Manager (VMM) and service
Better scaling from larger kernel address space
x64 systems typically can have more RAM
Increased Performance
Improved shadow page table management
Improved performance of guest process switching and memory intensive application
SQL team reported 100% performance improvement over R1
Exchange team reported 105% performance improvement over R1
65% increase in internal memory tests
Early customer saw a 50% drop in CPU utilization 5

6. Virtual Server R2: Enhancements (2 of 4)
Higher Availability
Virtual Server R2 Host Cluster support
The ability to cluster Virtual Server hosts
Virtual Server host clustering uses Windows Server 2003 EE/DTC clustering
Supports FC-SAN and iSCSI-SAN or direct attached storage
Planned downtime:
Servicing the host hardware or patching the host operating system. Virtual Machines (VMs) can be moved from one cluster node to another with minimal downtime
<10 seconds to move 128 MB vm via 1GbE iSCSI (1 spindle)
<4 seconds to move 512 MB vm via 2Gb FC (3 spindles)
<8 seconds to move 1 GB vm via 2Gb FC (3 spindles)
Unplanned downtime:
Failover to another cluster node due to hardware failure
Other benefits:
Guest operating system-agnostic
FREE 6

7. Virtual Server R2: Enhancements (3 of 4) Virtual Server 2005 R2 Host Clustering (planned downtime)
WSUS server
Administrator wants to update node 1 with Windows Server Update Services
Microsoft Cluster Administration Console saves the state of virtual machines and restores them on another node
Node 1 is ready for update installation
Shared Storage
Node 1
Node 2
Node 3 VM VM

8. Virtual Server R2: Enhancements (4 of 4) Virtual Server 2005 R2 Host Clustering (unplanned downtime)
Shared Storage
Node 1 suffers a power outage or a network failure
A simple script attached to the Microsoft Cluster Administration Console notices the lack of heartbeat and starts the virtual machines associated with node 1 on other nodes
Node 1
Node 2
Node 3 X VM VM VM

9. What’s New in SP1? Over 10,000 downloads of Beta 1 Beta 1 Features:
Intel VT (IVT) support
Service connection points support
> 64 VM support (x64 hosts only)
Emulated SCSI bug fix for Linux guests
Virtual Server host clustering step-by-step guide
Larger default size for dynamically expanding virtual hard disks
Beta 2 Features:
AMD-V support
Volume Shadow Service (VSS) support
Offline hard disk mounting service
Milestones:
Beta 2 publicly available as of 30/08/2006
Virtual Server 2005 R2 SP1 scheduled to ship in early H1/CY07

10. VSS Support Virtual Server R2 SP1 is VSS-aware
Now a new option for backups
Previously had to install agent inside each VM, or shutdown all VMs and back up the VHD
Technology is now implemented
Live backup capability support is being incorporated by backup vendors

11. Offline VHD Mounting One of the most requested features
Mount a VHD on the host’s file system
Offline manipulation of contents of the VHD
Inject files
Not a solution for offline patching
Virtualization team working with patching team regarding the offline-patching scenario

12. Summary Virtual Server 2005 R2 – Shipping today Released Q4 2004
Well received in the industry
Used for production server consolidation
Remote management of virtual machine operations
Great perf gains and functionality enhancement in SP1
64-bit host support, PXE support, and others 12

13. Monolithic vs. Microkernelized
Microkernelized hypervisor
Simple partitioning functionality
Increase reliability and minimize TCB
No third-party code
Drivers run within guests
Monolithic hypervisor
Simpler than a modern kernel, but still complex
Contains its own drivers model
VM 1
(“Admin”)
VM 2
VM 3
VM 2
(“Child”)
VM 3
(“Child”)
VM 1 (“Parent”)
Virtual-
ization
Stack
Hypervisor
Drivers
Drivers
Drivers
Drivers
Hypervisor
Hardware
Hardware 13

14. Windows Server Virtualization
Virtualization for Windows Server
Windows hypervisor
Uses Intel VT and AMD “Pacifica” virtualization extensions
Very thin layer of software below all OSes
Provides basic mechanisms for creating partitions
Does not contain device drivers
Virtualization stack
Runs as a foundation role with a minimal set of components
Provides the virtualization and emulation of devices
WMI interface for management and configuration
Virtualization Service Providers (VSPs)
Hardware sharing architecture
Microsoft will provide storage, network, video, USB, input, time 14

15. Windows Server Virtualization
Some proposed features
32-bit and 64-bit guests
x64-only hosts
Guest multiprocessing
Virtualized devices
WMI management and control API
Save & restore
Snapshotting
CPU and I/O resource controls
Tuning for NUMA
Dynamic resource addition & removal
Live migration 15

16. Hardware Requirements
First release of Windows Server Virtualization
Processor
Virtualization extensions
64-bit address extensions
Potential requirements for specific features in subsequent releases
Devices
Direct Device Assignment
IOMMU
DMA protections
Security
Secure Launch with TPM support

17. Windows Server Virtualization Architectural Overview
Parent Partition
Child Partitions
Kernel Mode
User Mode
Virtualization Service Providers (VSPs)
Windows Kernel
Server Core
IHV Drivers
Virtualization Service Clients (VSCs)
Enlightenments
VMBus
Windows hypervisor
Virtualization Stack
VM Worker Processes
VM Service
WMI Provider
Applications
Provided by:
Windows
ISV
OEM
Virtualization
“Designed for Windows” Server Hardware with PVE

18. The Hypervisor Very thin layer of software No built-in driver model
Highly reliable
Much smaller Trusted Computing Base (TCB)
No built-in driver model
Leverage the large base of Windows drivers
Drivers run in a partition
Will have a well-defined, published interface
Allow others to create support for their OS’s as guests
Hardware virtualization assists are required
Intel Virtualization Technology
AMD “Pacifica” 18

19. Hypervisor Design Goals
11/11/2018 3:25 PM
Hypervisor Design Goals
Strong Isolation
Security
Performance
Virtualization support
…and …
Simplicity
Restrict activities to monitoring and enforcing
Where possible, push policy up
Hardware
Windows hypervisor
Parent Partition
Server Core
Apps
Child Partition
OS 1
OS 2
© 2006 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION. 19

20. Physical Hardware
The hypervisor restricts itself to managing a minimum set of hardware
Processors
Local APICs
Constant-rate system counter
System physical address space
Focus is on scheduling and isolation
Hardware
Windows hypervisor
Parent Partition
Server Core
Apps
Child Partition
OS 1
OS 2

21. Physical Hardware
In Windows Server virtualization, the parent partition manages the rest
IHV drivers
Processor power management
Device hot add and removal
New drivers are not required
Hardware
Windows hypervisor
Parent Partition
Server Core
Apps
Child Partition
OS 1
OS 2

22. Hypercalls – Low Level API
Guests communicate with the hypervisor via hypercalls
Hypervisor equivalent of a syscall
Detected via CPUID
Configured via MSR
Simple format
One input page, one output page
Specify pages by physical address, then jump to known address

23. Hypercalls – High Level API
Higher level abstractions are available in Windows partitions
WinHv.sys provides a C language wrapper
VMBus.sys provides cross-partition communication services
Virtualization stack provides WMI interfaces for configuring children
Windows 2000 and later
Windows Server Core
WMI Provider
Virtualization Stack
WinHv.sys
VmBus.sys
WinHv.sys
VmBus.sys
Windows hypervisor
Hardware

24. Device Virtualization Definitions
11/11/2018 3:25 PM
Device Virtualization Definitions
Virtual Device (VDev)
A software module that provides a point of configuration and control over an I/O path for a partition
Virtualization Service Provider (VSP)
A server component (in a parent or other partition) that handles I/O requests
Can pass I/O requests on to native services like a file system
Can pass I/O requests directly to physical devices
Can be in either kernel- or user-mode
Virtualization Service Consumer (VSC)
A client component (in a child partition) which serves as the bottom of an I/O stack within that partition
Sends requests to a VSP
VMBus
A system for sending requests and data between virtual machines
© 2006 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION. 24

25. Virtual Devices (VDevs)
Come in two varieties
Core: Device emulators
Plug-in: Enlightened I/O
Management is through WMI
Packaged as COM objects
Run within the VM Worker Process
Often work in conjunction with a VSP

26. Virtualization Service Providers (VSPs)
Communicate with a VDev for configuration and state management
Can exist in user- or kernel-mode
COM object
Service
Driver
Uses VMBus to communicate with a VSC in the child partition

27. Example VSP/VSC Design
Parent Partition
Child Partitions
Kernel Mode
User Mode
Windows hypervisor
Applications
Provided by:
Windows
ISV
OEM
Virtualization
VMBus
Windows File System
Volume
Partition
Disk
Fast Path Filter (VSC)
iSCSIprt
Virtual Storage
Miniport (VSC)
Provider (VSP)
StorPort
Hardware
Miniport
VM Worker Process
“Designed for Windows” Server Hardware with PVE

28. Windows Enlightenments
Modifications to an OS to make it aware that it’s running within a VM
Windows codenamed “Longhorn” enlightenments
Optimizations in memory manager (MM)
Win32 and kernel API: Am I running on a virtual machine?
Looking at additional enlightenments in the future 28

29. Summary
Windows Server codename Longhorn will have integrated virtualization support
Hypercall interfaces can be used to support foreign operating systems
Remote management thru robust WMI I/F’s
Currently targeting Q4/2006 for private beta, Q1/2007 for public beta, & RTM within 180 days of Longhorn Server
Systems with processor virtualization extensions widely available from OEM’s today will be required.

30. Additional Resources MSDN for Virtual Server 2005 COM API
Windows Server Virtualization
Windows Hardware & Driver Central (WHDC)
Technical Communities
Non-Microsoft Community Sites
Microsoft Public Newsgroups
Technical Chats and Webcasts
Microsoft Blogs 30