Second Level Address Translation (SLAT) is a technology intended for reducing the overhead in a hypervisor CPU and eases the administration of a hypervisor’s memory. It is frequently found with Hyper-V. In Windows OS-based devices, including Windows 11, such capabilities can enhance the overall performance of virtual machines and simplify the overhead of hypervisor performance over its corresponding host system.
This technology is supported by both AMD and Intel processors. Intel processors are termed as Extended Page Table (EPT), whereas it is termed as Rapid Virtualization Indexing (RVI) in AMD processors. Intel has equipped this technology in their processors that are built on Nehalem Architecture. On the other hand, AMD equipped it in their third-generation Opteron processors termed Barcelona.
Nehalem microprocessors utilize a 45nm process and 4-12 MB L3 cache and an integrated memory controller that supports 2/3 memory channels. Conversely, Barcelona uses a shared L3 cache along with 128-bit floating-point units within an enhanced microarchitecture.
SLAT functions by including a cache in the system’s processor, which would store all the recent page table mappings generated by the hypervisor. This is termed as Lookaside Buffer (TLB). It supports physical memory translation. Essentially, it is a kind of cache that comprises all recently used mappings from the page table over the processor. Whenever it requires translation of a virtual address to a physical address, the TLB unit checks the same in the incorporated cache. So, it determines the corresponding mapping information. If a match is found, the hypervisor obtains the physical address. The same takes place without requiring the CPU or memory for translation.
In case it does not include the relevant mapping record, then a page error is shown. Moreover, the OS finds out the page table for the mapping detail. When the operating system finds out comparative mapping record, it will write the same in the TLB (Translation Lookaside Buffer). Consequently, the address translation occurs. If no match is found, the hypervisor will carry out a usual address translation after checking its traditional page table. As a result, it saves the TLB translation when it requires reference in the future.
This kind of Hyper-V (Hyper Visor) technology in Windows 11 devices utilizes more virtual memory management functions. Moreover, it decreases the translation overhead from a guest’s physical address to an actual physical address. Hence, it saves more memory to be used for further processing.
There are two methods that are available to check if your Windows 11 computer supports SLAT or not:
Method-1: Using the CoreInfo utility from Microsoft TechNet:
Firstly, download the CoreInfo archive from Technet through the below link.
Now extract the contents of the archive within the root of your OS partition.
Open Windows Command Prompt as an administrator and enter the following command to access the proper location:
After that, execute this command:
Based on the processor you use, you would receive an option for RVI or EPT and get the appropriate information regarding its availability.
From the Control Panel, open the ‘Turn Windows features on and off’ panel. This will open up the ‘Windows Features’ window on the screen.
Now expand the option for Hyper-V.
Within the ‘Hyper-V’ option, a subkey named ‘Hyper-V Platform’ is present. If the Hyper-V Platform’s option is greyed out, then SLAT is not supported.
To enable the SLAT feature, enable Virtualization in BIOS.