Editing X86 virtualization (section)

{{Short description|Hardware-assisted virtualization on x86/x86-64 CPUs}}
{{Lowercase title}}
'''x86 virtualization''' is the use of [[Hardware virtualization|hardware-assisted virtualization]] capabilities on an [[x86]]/[[x86-64]] [[Central processing unit|CPU]].

In the late 1990s x86 virtualization was achieved by complex [[software]] techniques, necessary to compensate for the processor's lack of hardware-assisted virtualization capabilities while attaining reasonable [[Computer performance|performance]]. In 2005 and 2006, both [[Intel]] ([[#Intel virtualization (VT-x)|VT-x]]) and [[Advanced Micro Devices|AMD]] ([[#AMD virtualization (AMD-V)|AMD-V]]) introduced limited hardware virtualization support that allowed simpler virtualization software but offered very few speed benefits.<ref>[https://web.stanford.edu/class/cs240/readings/hwsw.pdf A Comparison of Software and Hardware Techniques for x86 Virtualization, Keith Adams and Ole Agesen, VMware, ASPLOS’06 October 21–25, 2006, San Jose, California, USA] {{webarchive |url= https://web.archive.org/web/20221024045801/https://web.stanford.edu/class/cs240/readings/hwsw.pdf |date=2022-10-24}} "Surprisingly, we find that the first-generation hardware support rarely offers performance advantages over existing software techniques. We ascribe this situation to high VMM/guest transition costs and a rigid programming model that leaves little room for software flexibility in managing either the frequency or cost of these transitions."</ref> Greater hardware support, which allowed substantial speed improvements, came with later processor models.