3. Xen contributor community is diversifying
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
2010 2011 2012
Citrix UPC
SUSE Amazon
University AMD
GridCentric Individual
NSA Intel
Fujitsu iWeb
Misc Oracle
Spectralogic University of British Columbia
• The number of “significant”
active vendors is increasing
• New feature development driving
new participation
• Linux Foundation Collaborative
Project was next logical step
4. Xen : The Gears of the Cloud
• Large user base
more than 10 million individuals users
• Powers the largest clouds in production
• Not just for Servers
5. • Teams aka sub-projects
– Hypervisor
– XAPI
– ARM Hypervisor (for Servers as well as Mobile Devices)
– Mirage OS (a Xen Library OS)
• Governance : mixture between Linux Kernel and Apache
XenProject.org Overview
7. Hypervisor Architectures
Type 1: Bare metal Hypervisor
A pure Hypervisor that runs directly on the
hardware and hosts Guest OS’s.
Provides partition isolation + reliability,
higher security
Host HW
Memory CPUsI/O
HypervisorScheduler
MMUDevice Drivers/Models
VMn
VM1
VM0
Guest OS
and Apps
8. Hypervisor Architectures
Type 1: Bare metal Hypervisor
A pure Hypervisor that runs directly on the
hardware and hosts Guest OS’s.
Type 2: OS ‘Hosted’
A Hypervisor that runs within a Host OS and hosts
Guest OS’s inside of it, using the host OS services
to provide the virtual environment.
Provides partition isolation + reliability,
higher security
Low cost, no additional drivers
Ease of use & installation
Host HW
Memory CPUsI/O
Host HW
Memory CPUsI/O
HypervisorScheduler
MMUDevice Drivers/Models
VMn
VM1
VM0
Guest OS
and Apps
Host OS
Device Drivers
Ring-0 VM Monitor
“Kernel “
VMn
VM1
VM0
Guest OS
and Apps
User
Apps
User-level VMM
Device Models
9. Xen: Type 1 with a Twist
Type 1: Bare metal Hypervisor
Host HW
Memory CPUsI/O
HypervisorScheduler
MMUDevice Drivers/Models
VMn
VM1
VM0
Guest OS
and Apps
10. Xen: Type 1 with a Twist
Type 1: Bare metal Hypervisor
Host HW
Memory CPUsI/O
HypervisorScheduler
MMUDevice Drivers/Models
VMn
VM1
VM0
Guest OS
and Apps
Host HW
Memory CPUsI/O
Hypervisor
VMn
VM1
VM0
Guest OS
and Apps
Xen Architecture
Scheduler MMU
11. Xen: Type 1 with a Twist
Type 1: Bare metal Hypervisor
Host HW
Memory CPUsI/O
HypervisorScheduler
MMUDevice Drivers/Models
VMn
VM1
VM0
Guest OS
and Apps
Host HW
Memory CPUsI/O
Hypervisor
VMn
VM1
VM0
Guest OS
and Apps
Xen Architecture
Scheduler MMU
Control domain
(dom0)
Drivers
Device Models
Linux & BSD
12. Xen Project and Linux
• Xen Hypervisor is not in the Linux kernel
• BUT: everything Xen and Xen Guests need to run is!
– Linux Kernel 3.0+ is Xen-enabled
• Xen packages are in all Linux distros (except RHEL6)
– Install Dom0 Linux distro
– Install Xen package(s) or meta package
– Reboot
– Config stuff: set up disks, peripherals, etc.
More info: wiki.xen.org/wiki/Category:Host_Install
13. Basic Xen Concepts
13
Control domain
(dom0)
Host HW
VMn
VM1
VM0
Guest OS
and Apps
Memory CPUsI/O
Console
• Interface to the outside world
Control Domain aka Dom0
• Dom0 kernel with drivers
• Xen Management Toolstack
Guest Domains
• Your apps
Driver/Stub/Service Domain(s)
• A “driver, device model or control
service in a box”
• De-privileged and isolated
• Lifetime: start, stop, kill
Dom0 Kernel
HypervisorScheduler MMU XSM
Trusted Computing Base
14. Basic Xen Concepts
14
Control domain
(dom0)
Host HW
VMn
VM1
VM0
Guest OS
and Apps
Console
Memory CPUsI/O
Dom0 Kernel
Toolstack
HypervisorScheduler MMU XSM
Console
• Interface to the outside world
Control Domain aka Dom0
• Dom0 kernel with drivers
• Xen Management Toolstack
Guest Domains
• Your apps
Driver/Stub/Service Domain(s)
• A “driver, device model or control
service in a box”
• De-privileged and isolated
• Lifetime: start, stop, kill
Trusted Computing Base
15. Basic Xen Concepts
15
Control domain
(dom0)
Host HW
VMn
VM1
VM0
Guest OS
and Apps
Console
Memory CPUsI/O
One or more
driver, stub or
service domains
Dom0 Kernel
Toolstack
HypervisorScheduler MMU XSM
Console
• Interface to the outside world
Control Domain aka Dom0
• Dom0 kernel with drivers
• Xen Management Toolstack
Guest Domains
• Your apps
Driver/Stub/Service Domain(s)
• A “driver, device model or control
service in a box”
• De-privileged and isolated
• Lifetime: start, stop, kill
Trusted Computing Base
17. 17
Xen Hypervisor
Control domain
(dom0)
Host HW
Guest VMn
Apps
Memory CPUsI/O
Technology:
• Paravirtualization
Linux PV guests have limitations:
• limited to a subset of set of virtual HW
Advantages
• Fast
• Works on any system
(even without virt extensions)
HW Drivers
PV Back Ends PV Front Ends
Guest OSDom0 Kernel
PV Domains
18. 18
Xen Hypervisor
Control domain
(dom0)
Host HW
Guest VMn
Apps
Memory CPUsI/O
Technology:
• Paravirtualization
Linux PV guests have limitations:
• limited to a subset of virtual HW
Advantages
• Fast
• Works on any system
(even without virt extensions)
Driver Domains
• Security
• Isolation
• Reliability and Robustness
HW Drivers
PV Back Ends PV Front Ends
Driver Domain
e.g.
• Disk
• Network
HW Driver
PV Back End
Dom0 Kernel*
*) Can be MiniOS
Guest OSDom0 Kernel
PV Domains & Driver Domains
19. 19
Xen Hypervisor
Dom0
Host HW
Guest VMn
Technology:
• Shows emulation using QEMU/Device
Model (SW Virtualization)
• In other situation HW can be used
Disadvantages
• Emulation slower than PV
(mainly I/O devices)
Advantages
• No kernel support needed
Device Model
IO Emulation
IO Event
VMEXITDom0 Kernel
HVM
Memory CPUsI/O
20. 20
Xen Hypervisor
Dom0
Host HW
Guest VMn
Technology:
• Shows emulation using QEMU/Device
Model (SW Virtualization)
• In other situation HW can be used
Disadvantages
• Emulation slower than PV
(mainly I/O devices)
Advantages
• No kernel support needed
Stub Domains
• Security
• Isolation
• Reliability and Robustness
Device Model
IO Emulation
IO Event
VMEXIT
Stubdomn
Device Model
Mini OS
Guest VMn
IO Emulation
IO Event
VMEXITDom0 Kernel
HVM & Stub Domains
Memory CPUsI/O
21. The Virtualization Spectrum
Fully Virtualized (FV) VS VS VS VH
FV with PV for disk & network P VS VS VH
PVHVM P P VS VH
PVH P P P VH
Fully Paravirtualized (PV) P P P P
VH Virtualized (HW)
P Paravirtualized
VS Virtualized (SW)
HVM mode/domain
PV mode/domain
Xen 4.4
22. The Virtualization Spectrum
Fully Virtualized (FV) VS VS VS VH
FV with PV for disk & network P VS VS VH
PVHVM P P VS VH
PVH P P P VH
Fully Paravirtualized (PV) P P P P
Scope for improvement
Poor performance
Optimal performance
HVM mode/domain
Xen 4.4
PV mode/domain
23. The Virtualization Spectrum
Fully Virtualized (FV) VS VS VS VH
FV with PV for disk & network P VS VS VH
PVHVM P P VS VH
PVH P P P VH
Fully Paravirtualized (PV) P P P P
Scope for improvement
Poor performance
Optimal performance
HVM mode/domain
Xen 4.4
PV mode/domain
Important: Xen automatically picks the best
option based on HW & OS capabilities and
available drivers.
As a Xen user I chose a HVM or PV domain.
31. XAPI : What do I get?
Multiple Hosts
Additional Functionality
XAPI / XE
Xen Hypervisor
• VM lifecycle: live snapshots, checkpoint, migration
• Storage XenMotion: Migrate VMs between hosts or pools
without shared storage (while the VM is running)
• Resource pools: flexible storage and networking
• Event tracking: progress, notification
• Upgrade and patching capabilities
• Real-time performance monitoring and alerting
• Templates for Windows and Linux guests
• Open vSwitch support built-in (default)
More info: wiki.xen.org/wiki/XCP_Release_Features
34. System characteristics cloud users care about:
“Robustness, Performance & Security”
Results XCP User Survey 2013 – users quoted these as most important attributes
35. Split Control Domain into Driver,
Stub and Service Domains
– See: ”Breaking up is hard to do” @ Xen Papers
– See: “Domain 0 Disaggregation for XCP and XenServer”
Used today by Qubes OS and Citrix XenClient XT
Prototypes for XAPI
Disaggregation
See qubes-os.org
Different windows run
in different VMs
36. More Security
Increased serviceability and flexibility
Better Robustness
Better Performance
Better Scalability
Benefits of Disaggregation
Ability to safely restart parts of the system
(e.g. just 275ms outage from failed Ethernet driver)
38. CPUCPU
RAM RAMNIC
(or SR-
IOV VF)
NIC
(or SR-
IOV VF)
NIC
(or SR-
IOV VF)
NIC
(or SR-
IOV VF)
RAID
Xen
Dom0Network
drivers
NFS/
iSCSI
drivers
Qemu xapi Local
storage
drivers
NFS/
iSCSI
drivers
Network
drivers
Qemu
eth eth eth eth scsi
User VM User VM
NB gntdev NB
NF BF NF BF
qemu qemu
xapi
vswitch
networkd
tapdisk
blktap3
storaged
syslogd
vswitch
networkd
tapdisk
blktap3
storaged
tapdisk
blktap3
storaged
gntdev gntdev
Dom0
xenopsd
libxl
healthd
Domain
manager
Dom0
.
.
.
.
Xen
xapi
39. CPUCPU
RAM RAMNIC
(or SR-
IOV VF)
NIC
(or SR-
IOV VF)
NIC
(or SR-
IOV VF)
NIC
(or SR-
IOV VF)
RAID
Dom0 Network
driver
domain
NFS/
iSCSI
driver
domain
Qemu
domain
xapi
domain
Logging
domain
Local
storage
driver
domain
NFS/
iSCSI
driver
domain
Network
driver
domain
User VM User VM
NB gntdev NB
NF BF NF BF
dbus over v4v
qemu
xapi
xenopsd
libxl
healthd
Domain
manager
vswitch
networkd
tapdisk
blktap3
storaged
syslogd vswitch
networkd
tapdisk
blktap3
storaged
tapdisk
blktap3
storaged
gntdev gntdev
eth eth eth eth scsi
Xen Xen
D
o
m
0
dbus over v4v
.
.
.
40. 40
XSM is Xen equivalent of LSM
FLASK is Xen equivalent of SELinux
Developed, maintained and contributed to Xen by NSA
Compatible with SELinux (tools, architecture)
XSM object classes maps onto Xen features
Xen Security Modules (XSM) & FLASK
41. CPUCPU
RAM RAMNIC
(or SR-
IOV VF)
NIC
(or SR-
IOV VF)
NIC
(or SR-
IOV VF)
NIC
(or SR-
IOV VF)
RAID
Xen
Dom0 Network
driver
domain
NFS/
iSCSI
driver
domain
Qemu
domain
xapi
domain
Logging
domain
Local
storage
driver
domain
NFS/
iSCSI
driver
domain
Network
driver
domain
eth eth eth eth scsi
User VM User VM
NB gntdev NB
NF BF NF BF
qemu
xapi
xenopsd
libxl
healthd
Domain
manager
vswitch
networkd
tapdisk
blktap3
storaged
syslogd vswitch
networkd
tapdisk
blktap3
storaged
tapdisk
blktap3
storaged
gntdev gntdev
FLASK policy
restricting access
D
o
m
0
.
.
.
dbus over v4v dbus over v4v
Xen
42. 42
Xen Security Advantages
• Even without Advanced Security Features
– Well-defined trusted computing base (much smaller than on type-2 HV)
– Minimal services in hypervisor layer
• Advanced Security Features
– Xen has many Advanced Security Features
– Most are not switched on by default
– Although most are simple to use, some seen complicated
More info: http://www.slideshare.net/xen_com_mgr/
a-brief-tutorial-on-xens-advanced-security-features
44. ARM Servers Coming to Market
4GB RAM, 4 cores per node
3 x 6 x 4 x 4 = 288 cores per 4 RU
Xen for ARM Servers : Why ?
Single node virtualization capability
Manageability
45. Fully functional for ARM v7 & v8
ARM v7: Versatile Express, Arndale &
Samsung Chromebook
ARM v8: Fast Model
Xen 4.3 for ARM Servers
46. ARM SOC
Xen + ARM = a perfect Match
ARM Architecture Features for Virtualization
Hypervisor mode : EL2
Kernel mode : EL1
User mode : EL0
GIC
v2
GT
2 stage
MMU
I/O
Device Tree describes …
Hypercall Interface HVC
47. ARM SOC ARM Architecture Features for Virtualization
EL2
EL1
EL0
GIC
v2
GT
2 stage
MMU
I/O
Device Tree describes …
HVC
Xen + ARM = a perfect Match
Xen Hypervisor
Dom0
only
Any Xen Guest VM (including Dom0)
Kernel
User Space
I/O
PV
back
PV
frontI/O
HVC
48. One mode to rule them all
x86: PVHVM P P VS VH
x86: PV P P P P
ARM v7 & v8 P VH VH VH
Scope for improvement
Optimal performance
HVM mode/domain
PV mode/domain
50. • Release candidates & Xen Test Days (June 5th)
• Xen ARM for Servers
• Extend scope of Xen Security Modules
• Default to QEMU upstream
• Updated and improved libvirt drivers for Xen
• Lots of other stuff:
– scalability, performance, better NUMA support, …
Xen 4.3 Release (June 2013)
More info: http://lists.xen.org/archives/html/xen-devel/2013-05/msg01134.html
51. “For about a year members of the Xen Project, the CentOS community
and large Xen Users have worked on bringing Xen and XAPI to
CentOS 6”
Driven by demand from the community :
• Can run Xen on CentOS 6 today, but non-trivial
• We wanted “YUM INSTALL XEN”
• Mostly a packaging problem
• Teams from CentOS, Citrix, Go Daddy & Rackspace
• QA and usability sanity checks
Xen 4 + XAPI in CentOS 6 (June 2013)
52. “Growth is leading to more structure & more collaboration & more openness!”
• Establishing a shared and open test infrastructure
– Goal: Increase development velocity and quality
• Improved usability and better distro-integration
– Xen + XAPI in CentOS 6.4
• More focus on downstreams
– OpenStack and Xen Orchestra
– Better libvirt and virt-manager integration
• Changing the XAPI / XCP release model
• Xen on ARM and collaboration with Linaro
The Xen Community is Changing
53. Online : xenproject.org > User & Help menus
• Mailing Lists and IRC
• Q&A System
• Find me and I can get you hooked up!
Events : xenproject.org/about/events.html
• Test Days (IRC at #xentest) … next one June 5th
• Document Days (IRC at #xendocs) … the next one is June 24th
• User (Sept 18, New Orleans) and Developer Summits (Oct 24-25, Edinburgh)
• Hackathons – see http://blog.xen.org/index.php/2013/05/28/
event-report-xen-hackathon-2013/
Getting Started with Xen Projects
54. Thank You!
Slides available under CC-BY-SA 3.0
From www.slideshare.net/xen_com_mgr
@lars_kurth
FREENODE: lars_kurth
• News: blog.xenproject.org
• Web: xenproject.org
– Help for IRC, Lists, …
– Stackoverflow like Q&A
• Wiki: wiki.xenproject.org
• Presentations: slideshare.net/xen_com_mgr
• Videos: vimeo.com/channels/xen
Editor's Notes
Key points not on the slides:Governance: same roles, same license, DCO, …Vendors: the link shows a breakdown of contributions to Xen 4.2
Key points not on the slides:Governance: same roles, same license, DCO, …Vendors: the link shows a breakdown of contributions to Xen 4.2
Color code: green + bright green = trusted computing baseType 1 hypervisor: example ESXSimple architecture; Hypervisor replaces the kernel entirelyNo need to provide rich “process” semantics, like “user”, filesystems, etc.BUT: Device drivers and Device Models need to be rewritten for each hardware platformThis meansisolation and higher security by designis traded off against maintainability and re-use of driversType 2 is hosted: example KVM- The hypervisor is just a driver that works with user-level monitor and the host OS kernelHW access is intercepted by the ring 0- VM monitor passed to the User level Virtual Monitor, which passes requests to the kernelThis meansRe-use of device drivers and host OS kernel infrastructureis traded off against security and a large trusted computing base
Color code: green + bright green = trusted computing baseType 1 hypervisor: example ESXSimple architecture; Hypervisor replaces the kernel entirelyNo need to provide rich “process” semantics, like “user”, filesystems, etc.BUT: Device drivers and Device Models need to be rewritten for each hardware platformThis meansisolation and higher security by designis traded off against maintainability and re-use of driversType 2 is hosted: example KVM- The hypervisor is just a driver that works with user-level monitor and the host OS kernelHW access is intercepted by the ring 0- VM monitor passed to the User level Virtual Monitor, which passes requests to the kernelThis meansRe-use of device drivers and host OS kernel infrastructureis traded off against security and a large trusted computing base
Thinner hypervisorOnly Contains: Scheduler and Memory Management
Thinner hypervisorOnly Contains: Scheduler and Memory Management
Domain 0:Special Virtual Machine that co-operates with the HypervisorContains a Xen enabled Kernel: Linux 3.x or NetBSDUses Device Drivers and Device Models (QEMU)For Linux: Using Linux PV OPSExposes support for various virtualization modes: PV, PV on HVM and PVH modesSharing components with KVM (e.g. QEMU based Device Drivers)
As we talked a little bit about Xen and Linux already it is worth point out a few things to Xen and LinuxSome people argue that KVM is better than Xen, because KVM is in the kernelThis argument is bogusSoftware should be compared on the basis of features and system characteristicsNOT on where the source code livesSo, although Xen is NOT in the Linux KernelBUT from linux 3.0 onwards EVERYTHING that Xen and Xen Guests need to run isAnd all modern Linux distros (with the exception of RHEL6) contain Xen packagesTHIS MEANS:The user experience for Linux users for Xen and KVM is VERY similarYou choose your favourite distro and install (that is true for Xen and KVM)You download and install the Xen packages (KVM-QEMU package) via your package managerTHE only difference is that for Xen you reboot, after which Xen runs underneath your Dom 0Then you configure your systemThe point is: from a users perspective it doesn’t matter whether Xen is in Linux or not, as long as distros contain Xen packages
This is the architecture that we have explained beforeLet’s add a few more things!
Added theToolstackExposes an RPC type interface such that the system can be controlled from the outside worldXen has a few options for toolstacks (see later)Added the ConsoleA CLIA UIOr an interface to a cloud orchestration stack Controls the system (for operations such as starting, stopping VMs, etc.)
A unique feature of Xen is called disaggregationThis means:I can take a Device DriverA Device ModelA service (e.g. the toolstack)That normally runs in Domain 0 and run it in a separate VM.That VM is de-priviliged (it is not part of the trusted computing base)It can be restarted (if needed) without affecting the rest of the systemThis is something unique to Xen’s architecture. More later.
Remember the concept of disaggregation I mentioned earlier?With Driver Domains, I can take an individual driver (e.g. disk or network) and run it in its own domain (aka VM)In terms of how PV works: it is exactly the same as with drivers running in Dom0, only that Xen knows that the driver runs in its own driver domain
Device Model emulated in QEMUModels for newer devices are much fasterBut for IO operations PV is even faster
Remember the concept of disaggregation I mentioned earlier and Driver Domains?Stub Domains: Run an individual device model (QEMU instance) in its own domain Again, these work identical to Device Models within a Dom0.For scalability there is one stub domain per VM
On Xen.org, you will come by two main projects:The Xen HypervisorThe Xen Cloud PlatformAt a very high level, we will you show you the various options to build a system.
Let’s first look at choices of Xen Management Toolstacks:The Default with XL as CLI console Single Host, with basic functionalityLibvirt with VIRSH as CLI console (can also use virt-manager)Multiple Hosts, more functionalityXAPI (or Xen API) and XE as CLI (a number of UI options available)Multiple Hosts, even more functionality than LibvirtTypically when a Xen system contains XAPI, we call it Xen Cloud Platform
Lots of services use various of these combinationsWe picked out a few for these different configurationsAWS uses Xen with DefaultSuse Cloud uses Xen with LIBVIRTRackspace Cloud Servers uses XAPIThere are loads more large users: check out en.org/community/ecosystem.html If you want to know more about AWS and Rackspace, check out xen.org/community/presentations.html We also have some user case studies
A number of different commercial products use these combinations:Oracle VM based on Xen, the default stack with additionsHuawei UVP, which uses Xen + LibvirtCitrix XenServer which uses Xen + XAPI
Lots of services use various of these combinationsWe picked out a few for these different configurationsAWS uses Xen with DefaultSuse Cloud uses Xen with LIBVIRTRackspace Cloud Servers uses XAPIThere are loads more large users: check out en.org/community/ecosystem.html If you want to know more about AWS and Rackspace, check out xen.org/community/presentations.html We also have some user case studies
This is information from our own XCP survey (Q4 2012).Basically users were asked to rate system attributes according to importance on a scale of 1-5 90% of all users that use XCP for the cloud ratedRobustness, Performance, Scalability and Security at a 5Many other system attributes ranged from 3-4
We introduced disaggregation earlier under architectural concepts. To remind you, in a nutshell it means distributing system components running in Dom0 into separate VM’s.If you want to know more about the concept: There are the two papers listed above.The first takes disaggregation to the extreme!Disaggregation is in use by OSS and commercial products for Desktop Was originally developed for NSA:Every person with a specific security clearance has to have one terminal (desktop computer) per clearance levelTypically every employee had several TerminalsProducts using disaggregation are deemed secure enough by the NSA (and similar orgs) to Prototypes for server and cloud products
Good for SecurityReduces Trusted Computing BaseBetter defined interfaces (better for security audits)Can kill-start domains on a timer to wipe security risksIt is also good for robustness:You can basically restart parts of the system without affecting the rest of the system Latency for this is low (see the graph – in the order of 100 of ms)Incidentally this is also good for serviceability: in other words I can upgrade parts of my system while leaving others untouched and runningGood for performance and scalability:Removes Dom 0 as a bottleneck when many VM’s are runningPlaces more emphasis on the Xen scheduler vs. the Dom0 scheduler, which tends to lead to better performanceYou can chose better performing OS+driver combinations (e.g. BSD)
This shows a diagram of the type of services running in a normal XCP instance.The picture shows:1) Two Hosts2) User VMs per Host (on top instead of on the side due as in due to space constraints on the slide) 3) Dom0 with Xen per host (green boxes – also Trusted Computing base)4) Services and processes running within each Dom0Note: that inter-host communication is handled by the XAPI component Also note: this is an approximation as there is not enough space to cram everything in! There is stuff missing!NOW LETS LOOK WHAT DISAGGREGATION DOES!
This shows a diagram of the type of services running in the XCP disaggregation prototype.What is different:Key services are running in their own domainsEach host has a fast inter-domain communication mechanism called DBUS that allows direct VM to VM communicationThe Trusted Computing base has become a lot smaller (look at the green)
Now looked at disaggregation:It is worth to remind ourselves of existing Xen Security advantages: more modular, smaller TCBThere are also additional features, the most noteworthy is XSMDeveloped and maintained by the NSA (who contribute 3-4% of code per year to Xen)Follows the same architecture as SELinux (including compatibility with policy checking and dev tools for SELinux)Can be used together with SELinuxThe main difference is that XSM exposes objects that map to Xen featuresAlthough XSM alone is useful, it becomes REALLY INTERESTING when used with disaggregation!See WHY IN THE NEXT SLIDE!
The RED BOX, shows how we can use XSM and SELinux to secure our system.Per domain, I can restrict what can be started in a domainI can restrict what hypervisor interfaces (PV or hypercalls) a class of domain can access. In this example, I can ensure that only Linux and Xen functionality that is necessary to operate the Network Driver Domain can be accessed or launched
Now looked at disaggregation:It is worth to remind ourselves of existing Xen Security advantages: more modular, smaller TCBThere are also additional features, the most noteworthy is XSMDeveloped and maintained by the NSA (who contribute 3-4% of code per year to Xen)Follows the same architecture as SELinux (including compatibility with policy checking and dev tools for SELinux)Can be used together with SELinuxThe main difference is that XSM exposes objects that map to Xen featuresAlthough XSM alone is useful, it becomes REALLY INTERESTING when used with disaggregation!See WHY IN THE NEXT SLIDE!
A unique feature of Xen is called disaggregationThis means:I can take a Device DriverA Device ModelA service (e.g. the toolstack)That normally runs in Domain 0 and run it in a separate VM.That VM is de-priviliged (it is not part of the trusted computing base)It can be restarted (if needed) without affecting the rest of the systemThis is something unique to Xen’s architecture. More later.
A unique feature of Xen is called disaggregationThis means:I can take a Device DriverA Device ModelA service (e.g. the toolstack)That normally runs in Domain 0 and run it in a separate VM.That VM is de-priviliged (it is not part of the trusted computing base)It can be restarted (if needed) without affecting the rest of the systemThis is something unique to Xen’s architecture. More later.
