Talk:X86 virtualization

List of Processors with Nestded Virtualization support in Hardware
How about adding a list of Intel and AMD processors that do or don't support this AMD-V or V-x mode in hardware? A reference like that is important because otherwise people apparently have to search each model for the feature?

2005 topic
Maybe I don't understand the topic, but weren't there x86 virtalization products long before VMWare? VirtualPC and SoftWindows95 come to mind. Anirvan 23:46, 19 Apr 2005 (UTC)


 * The article is specifically addressing the case of virtual machine monitors for carving up an x86 machine into multiple virtual x86 machines. This is not as easy a task as one might imagine, which is why some pretty nifty technology is required. Mark Williamson 18:14, 20 Apr 2005 (UTC)

Enabled

 * Maybe someone can research the following, provide citations. I don't have time myself.

Due to pressure from Microsoft (No citations available*), Intel's VT and AMD's V technologies have been proactively disabled in many desktop/laptop bioses. This is to prevent people from easily testing out alternate operating systems at full speed. It is -not- a technology which needs Bios support.

Intel had their own software development labs which created technologies in the past, Microsoft saw as a threat, and under pressure from Microsoft, Intel closed those efforts. Meanuwhile, Intel has been promoting alternate operating systems, such as desktop Linux. Microsoft's control of Intel is not as strong as their control of the hardware marketers, like Dell, and every large PC and laptop hardware vendor.


 * the logical conclusions can be supposed from existing circumstantial evidence and past records of actions, and from comments from engineers in companies which have commented they were told to specifically disabled VT/V in the Bios for no good reason. 39xb20xc (talk) 09:35, 11 August 2008 (UTC)
 * Eh? You don't need VT for Virtualization. You can even download a ‘’free’’ application from Microsoft that can run alternate operation systems such as Ubuntu at full speed on CPU's ‘’lacking’’ VT and AMD V. What VT does is make Virtualization easier, but neither Virtual PC nor VMWare needs it and as for “full speed”, according to benchmarks VT is actually slower than both Virtual PC and VMWare. Disabeling VT to prevent Windows from virtualizating Linux is in that light pointless, OTOH Linux may not have any free virtualizers that can run Windows without the VT or AMD V feature (I don't know).Anss123 (talk) 13:23, 11 August 2008 (UTC)
 * I don't know anything regarding Windows, but I've tried running Mandriva linux in another Mandriva linux box by the means of VirtualBox. It failed starting with an error message saying that I have AMD-V disabled, but it is required for running 64-bit guest. It turned out, I had an option in BIOS setup called something like «Secure virtualization» set to «Disable». --213.180.99.197 (talk) 17:25, 15 February 2010 (UTC)

Merge
Perhaps this article and Virtualization Technology should be merged? They both try to discuss hardware and software virtualization on the x86 architecture. -- Bovineone 18:51, 15 February 2006 (UTC)

=>Mabye, mabye not, first they should both be cleaned up. Second, they should be seperated and cleaned so that Virtualization Technology should contain implemented hardware (with accompying software) techniques, where X86 virtualization should discuss generic techniques involved (ring 0 and the like). But I agree, at the mement they are both very similar. --220.237.182.188 10:21, 20 February 2006 (UTC)

I agree that they should not be merged. Virtualization Technology is about a very specific hardware feature, while X86 virtualization is about virtualization on x86 processors in general. Surely the latter should link to the former, but including the former in the latter would be putting too much specific information in a general article. ThinkingInBinary 22:06, 7 April 2006 (UTC)

I think they probably should be merged, since both are quite short, and the data in Virtualization Technology is highly relevant for the future of virtualization on x86. However, if they're not, then at least the name of the Virtualization Technology article needs to be changed. It's an incredibly general name, sounding far more general than the name of the X86 virtualization article, while in fact being much more specific. It should properly be named something like AMD and Intel hardware features for virtualization (horrible name) or some such. JZ 17:52, 12 April 2006 (UTC)

How about Hardware X86 Virtualisation? RealLink 11:48, 14 April 2006 (UTC)

Surely the other way round, Virtualization Technology can cover ALL types of Virtualization, where as X86 Virtualization can only cover a subsection.... --NigelJ talk 02:44, 30 April 2006 (UTC)


 * The phrase "Virtualization Technology" in that capitalization refers specifically to the name being used by Intel and AMD for the hardware-assisted virtualization features, not something more general than that. -- Bovineone 06:47, 18 June 2006 (UTC)

There doesn't seem to be enough non-x86 information here to justify separate pages. Even including a little information about IBM and HP virtualization won't really do it. The pages can always be separated later when sufficient material is available. Also, the information under the Use heading on the Xen page looks like it would fit well here. Zik 16:52, 8 May 2006 (UTC)


 * Agreed, since both articles were relatively short and overlapped in some areas content, I've just merged them. -- Bovineone 06:47, 18 June 2006 (UTC)

Cite sources tag?
Under "Software utilizing VT," and "The following software is known to conditionally make use of virtualization technology features:" Microsoft Virtual PC has a "citation needed" tag... doesn't the link cite itself? Maybe I'm not quite getting what the list is specifically speaking of, but isn't the added html comment "since what version?" is answered by the link as well... right? Again, I might just be missing what the list is specifying. -- KyleP 00:39, 14 October 2006 (UTC)

Would love to know where people think the 939 processors don't support AMD's Virtualization, I have two 939's here that are Virtualization enabled, so this is misleading. 75.71.217.152 (talk) 05:02, 3 October 2008 (UTC)

x86 virtualization is the method by which the x86 processor architecture is virtualized
Recursive definitions are uninformative, in general. Can someone come up with a definition which is actually helpful? I admit to being at a loss for one at the moment. --Scott McNay 00:54, 6 November 2006 (UTC)

Virtualization describes a process by which a CPU is shared between multiple operating systems, each of which believes it has the CPU in supervisor mode. Virtualization of x86 processors from i386 and up has required "emulating" Ring 0-specific instructions in software. Ring 0 is the "supervisor" mode where protected OS functions are controlled. These supervisor functions can include shutting down the CPU and disabling/enabling interrupts. Newer x86 and x86_64 architecture chips provide instructions which offer Ring 0 work-alike functions that do not affect the overall CPU, but only the specific virtual CPU, allowing the virtualization software to delegate the trapping of Ring 0 instructions to the hardware. --Anonymous contributor 9:19, 16 May 2007 (UTC)

Popek/Goldberg, x86 virtualization and the tone of the opening pp
I disagree with the spirit of the opening statement. Popek and Goldberg guidelines are, as openly stated within their paper, only general and not a list of "necessities". Virtualization on the x86 platform evolved quite nicely over the years well before the advent of AMD-V and Intel-VT. Even now, the leading virtualization technologies are only beginning to take advantage of the very early hardware support that the AMD and Intel extensions are adding. It is not until the next wave of hardware support that virtualizes I/O, and the next wave of virtualization products that are optimized to take advantage of hardware extensions fully and capitalize on the advances of Intel-VT-d and AMD-V+1, that we will really understand the implications of hardware supported virtualization on the x86 platform. Despite that, there are many real-world production case studies of VMWare and Virtual Server being utilized on a large-scale today. The article implies that Popek-Goldberg somehow establishes a gospel for what is absolutely mandatory to have successful virtualization and that, it is only now, that the x86 platform has "met the requirements" that it can be done "easily". That is all a dramatic oversimplification. —The preceding unsigned comment was added by Mlambert890 (talk • contribs) 06:35, 8 January 2007 (UTC).

is the virtualization detectable from the guest?
Can a guest detecht if it is running as a guest within a hypervisored environment? If not it should be possible that it starts its own hypervisor and the virtualization can be nested endlessly, right? --84.72.190.27 13:22, 26 March 2007 (UTC) (de:Benutzer:RokerHRO)
 * The presence of a hypervisor is usually made known to a guest OS in order to prevent this scenario. According to this thread it is also possible to detect running as a guest, even if the hypervisor does not advertise this state. 95.112.101.51 (talk) 15:16, 2 July 2013 (UTC)


 * Several hypervisors actively try to hide themselves, and make the VM think it is running on bare metal. For example, this is used in virus detection, a virus researcher (or AV company) may create a VM and infect it with a virus to monitor its actions. Several virus actively look to see if they are running in a VM and if so, then they do nothing. They look for things like VMware drivers, etc. sneakier hypervisors can use generic are "real" drivers, but then there are other methods of attack, like looking for known x86 processor arithmetic errors that were not properly emulated. Then the hypervisor can try and emulating them, it is a clear cat-and-mouse game. ADNewsom (talk) 18:48, 31 July 2013 (UTC)

Blog links
Should we really be linking to these? What are the criteria for inclusion?24.127.51.40 21:21, 25 April 2007 (UTC)

Windows Vista and Virtualization
The following article argues that Windows Vista Home Basic and Premium may be installed on a virtual machine, *if* the accompanying license is not otherwise in use:

http://blogs.zdnet.com/Bott/?p=157

Microsoft reacted and explained, that the cheapest versions of Vista really cannot be used as guests

Urocyon 18:36, 4 May 2007 (UTC)

buying a secure IOMMU
How is a buyer supposed to know which systems have secure (isolating) IOMMUs? These are needed for crash protection and malware sandboxing.

AMD: All chips have some IOMMU, but mostly they are not secure. Which model numbers are secure? What about motherboard chipset requirements? One would need to have each PCI slot be a separate bus, in practice meaning PCI Express.

Intel: As with AMD, what CPU models and what motherboard chipsets? There is a worse problem with Intel though. Unlike AMD, Intel allows the BIOS to disable features at boot -- and the PC vendors actually do this!

24.110.144.116 03:24, 16 July 2007 (UTC)

Performance benefit ?
What is the performance benefit of hardware assisted virtualization ? The only data I could find is from 2006 by VMWare A Comparison of Software and Hardware Techniques for x86 Virtualization. From its results it seems HW virtualization has no performance benefit. Is there newer data about this issue ? --Xerces8 (talk) 15:37, 26 March 2008 (UTC)

Para-virtualization will generally out-perform pure virtualization. The best hardware support can do is to reduce the penalty (by reducing the number of traps required). This is what Intel and AMD are doing. Heiser (talk) 05:18, 27 March 2008 (UTC)

Intel Core2 Duo E7300 mistake
To the contrary of what section «Virtualization for IA32» says, Intel Core2 Duo E7300 do *not* include VTx as per http://www.intel.com/products/processor/core2duo/specifications.htm. I do have one and it doesn't include VTx. The article should be updated. 83.99.66.90 (talk) 14:12, 15 December 2008 (UTC) V. Cadet

Athlon 2400
I suppose Athlon 2400 does not support this according to the web page? Is there a proogram to run to tell for sure or a list of all processors with a check off of whether it has this feature or not?
 * CPUZ can check for the feature, but you do not need it for virtualization. Just download VirtualBox (free) and you're good. Hardware based virtualization is only needed for 64-bit OSes - something a 2400+ does not support anyway.--Anss123 (talk) 00:30, 20 February 2009 (UTC)

Contradiction with Zen, VT and Windows
On this wikipedia page the statement: http://en.wikipedia.org/wiki/X86_virtualization#Intel_Virtualization_Technology_for_x86_.28Intel_VT-x.29

"Xen — Xen is a separate and independent operating system that virtualizes everything else on the machine. It supports both architectures, but does not require them for supported guest OS's."

Now on the Zen Page the statement "http://en.wikipedia.org/wiki/X86_virtualization#Intel_Virtualization_Technology_for_x86_.28Intel_VT-x.29

"Xen version 3.0 introduced the capability to run Microsoft Windows as a guest operating system unmodified if the processor supports hardware virtualization provided by Intel VT (formerly codenamed Vanderpool) or AMD-V (formerly codenamed Pacifica)."

So what is the answer? Does Windows on Zen need Intel-Vt / AMD-V hardware assistance to run under Xen? The Xen pages says yes you do need it and the X86 Virtualization page says No you don't need it. Facts need to be checked. 67.174.7.187 (talk) 23:24, 12 August 2009 (UTC)
 * for what i remember, it should go as such (but don't blindly trust my memories, do check it):
 * 1) Xen 0.x was not a virtual machine, it was virtual OS. That is: it used specially altered (so called 'host') Linux (kernel of GNU/Linux operating system) to run simultaneously a bunch of specially (but differently) altered 'guest' Linuxes, each of those loaded its own separate virtualised GNU/Linux and the programs in them.
 * 2) This was relied on FLOSS state of Linux. It might also be extended to FreeBSD kernel (also FLOSS) but not on the Windows kernel.
 * 2.1) Hardware virtualisation really did not matter for "Virtual operating system" approach - all required changes were made directly into Linux source files.
 * 2.2) Since XEN does not possess neither sources nor license grants for Windows kernel they could not make (and run) "virtual Windows OS" on top of altered Windows kernels.
 * 3) adding to this old abilities, the version XEN 3.0 introduced full-featured virtual machine, capable of running proprietary OS like Windows, if assisted by hardware VT
 * 3.1) older XENs than 3.0 can not run Windows on any hardware
 * 3.2) Even modern Xen can not run Windows without hardware VT
 * 3.3) But both Xen 3.0 and older XENs can run GNU/Linux and maybe other FLOSS operating systems without hardware VT
 * So, no contradiction, u c. 79.111.223.5 (talk) 21:37, 12 May 2011 (UTC)

T5500
Here T5500 was reported to support virtualization, but at least my notebook's T5500 does not contain it. —Preceding unsigned comment added by 130.234.117.12 (talk) 09:48, 12 August 2009 (UTC)

Can someone add that AMD-V is not HV and hwMMU?
Can someone add that AMD-V is not real HV and hwMMU (RVI)?

It seems that regular consumer processors with AMD-V only support BT, and not HV and hwMMU with the 4th generation server processor Operons? —Preceding unsigned comment added by 99.243.207.3 (talk) 14:07, 16 January 2010 (UTC)

Intel Core 2 Duo T5500 and VT-x
Although it's stated that only SL9U8 of T5500 model has Vt-x, Intel product info shows that it's not true. All SKUs of T5500 have VT-x feature. This needs to be fixed. —Preceding unsigned comment added by Parsek77 (talk • contribs) 20:39, 17 February 2010 (UTC)
 * Either the product info or the processorfinder has incomplete information. The processorfinder lists VT only for SL9U8. --Virtimo (talk) 13:57, 18 February 2010 (UTC)
 * In the case of the T5500 the issue was clarified in a forum post by an Intel representative. So from a purist point of view the product info on Intels website is incomplete, but the feature should be regarded a bonus on certain T5500 SKUs according to Intel, while it certainly shouldn't be expected in general on this model. --SCF0 (talk) 02:13, 11 November 2010 (UTC)

March 2010
If you dont have a computer background, you cannot understand this page. What the hell is the point of these virtual machines? What does virtual mean in this context? Needs a top to toe re-write. 124.171.42.238 (talk) 23:30, 19 March 2010 (UTC)

AMD Turion™ 64 X2 have not virtualization support
Not all of AMD Turion have virtualization support. Have virtualization support: - AMD Turion™ X2 Dual-Core (RM-7X) - AMD Turion™ X2 Ultra Dual-Core (ZM-8X) - AMD Turion™ Neo X2 Dual-Core (L625, K625, K655) - AMD Turion II Dual-Core (N530, P520, M5X0) - AMD Turion II Ultra Dual-Core (M6X0) Have not virtualization support: - AMD Turion™ 64 X2 Dual-Core (TL-5X, TL-6X)

http://products.amd.com/en-us/NotebookCPUResult.aspx —Preceding unsigned comment added by Bozaro (talk • contribs) 17:17, 1 June 2010 (UTC)
 * Contrary to this, my Compaq F504EA Notebook with a TL-52 has the option to toggle AMD-V in the BIOS and if it is enabled then Windows Virtual PC is able to run without the hotfix, confirming that the functionality is indeed there. 86.21.32.83 (talk) 02:08, 8 August 2010 (UTC)

Renamed and moved sections
I renamed sections, moved sections, added a new section called "Chipset" and bumped up the subsections under it since those are part of the chipset instead of the CPU, merged 64-bit sections, and added more references. If I made any mistakes, please correct instead of doing a bulk "undo", and please no throwing rocks at me :-) •  Sbmeirow  •  Talk  •  08:50, 10 January 2011 (UTC)


 * Great job! Can I throw marshmellows?
 * Do you think "Memory and I/O virtualization is performed by the chipset" is too tied in to current designs rather than an innate feature of virtualization? On the low end, System On a Chip designs are already putting the chipset in the CPU, and I expect that trend to continue.  See http://www.eetimes.com/General/DisplayPrintViewContent?contentItemId=4027661 and http://www.thegurureview.net/aroundnet-category/intels-oak-trail-chip-to-do-well-in-the-tablet-space.html for a couple of interesting examples.   Guy Macon  12:16, 10 January 2011 (UTC)


 * It's very cold here, so throw some marshmallows in my hot coca.
 * It's correct for multi-chip designs, but as integration combines more and more logic into fewer chips, like Atom and Bobcat, then "chipset" isn't correct. What other word or short description could we use instead of "chipset" for the section name?  Ideas?  <<<<<
 * My point of moving those things under chipset was to make it obvious those virtualization features were NOT special software intructions. Maybe there is some other way to make this point obvious?  Ideas?  <<<<<
 * More text needs to be added and this articles needs further refinement. I didn't add a bunch more because I didn't want to waste a lot of time on text if people wanted to undo my big changes.
 * • Sbmeirow  •  Talk  •  23:56, 10 January 2011 (UTC)

VIA Nano processors ?
Here is press-release for 4-core Nano CPU: http://www.via.com.tw/en/resources/pressroom/pressrelease.jsp?press_release_no=5507 It is caimed that in 4-core Nan (as well as in some 2-core Nano X2-E ) there is "VIA VT" hardware virtualisation. Did anyone saw reviews of it ? how it compares with AMD-V and Intel VT ? Does it have software support ? etc 79.111.223.5 (talk) —Preceding undated comment added 21:20, 12 May 2011 (UTC).

references ?
refs 320 n 330 - seems to be exactly the same. Can wiki merge them and use same number for both ? —Preceding unsigned comment added by 79.111.223.5 (talk) 19:38, 13 May 2011 (UTC)

WP:NOTHOWTO
Please do not add tests to check whether a system has virtualization on or not. This violates our policies on what Wikipedia isn't. Also, please do not use the word "you" in the article per WP:MOS. Thank you.Jasper Deng (talk) 05:24, 14 June 2011 (UTC)
 * Don't see how describing the processor bits violates nothowto. On the other hand, the OS-level checks might, but then it's only a few words. Someone not using his real name (talk) 17:41, 17 February 2014 (UTC)

Redirect from VT-i?
I'm writing this article on Japanese Edition now, taking the section of this article into account.

I noticed that VT-i (Virtualization/Vanderpool Technology for the Intel Itanium Architecture) was redirected by this article, but this article does not mention VT-i.

I don't have a good command of English, so I wish it is revised in some way. --61.89.14.86 (talk) 04:39, 9 February 2012 (UTC)


 * [report] Because I found that 'Intel VT-i' was redirected from 'Itanium', I edited 'VT-i' and redirected to proper section 'Itanium'. --61.89.14.86 (talk) 00:12, 13 February 2012 (UTC)

External links modified
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