Pros/cons of enabling virtualization?

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WilyKit

Gawd
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Dec 18, 2020
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I was going through HWInfo with a fine tooth comb just to learn more about my hardware and noticed that one of the CPU features, (virtualization) is “supported” but not enabled. I’m pretty sure the switch is somewhere in the bios. Is there any benefit, or for that matter, drawbacks to enabling it? Is there a reason it’s disabled by default?
 
I have often wondered about that as well. Checked google. There were some root kits that could exploit it and there are some kernel functions that can't use the fastest instructions on certain tasks if it is enabled. If that is still the case. I don't know.
Would be interesting to see some benchmarks. I bet it is of negligible impact.
 
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Yeah, afaik, there are a few potential security implications. There are also some applications which take advantage of the virtualization features, but you'd probably know if you used them (they usually advertise it pretty aggressively if there's a decent performance benefit, but even if they don't it's usually obvious when you run the program that it's struggling).
 
pendragon1 said:
its not needed for 98% of users so its defaulted to off.
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There has to be more to it than that. 98% of users would also not make use of 32GB of ram if they had it, or a 4TB hard drive but the computer doesn't block off half of it so I'm thinking there has to be a reason it is disabled above and beyond how often it gets used. Potential security and performance issues make sense if accurate.
 
WilyKit said:
There has to be more to it than that. 98% of users would also not make use of 32GB of ram if they had it, or a 4TB hard drive but the computer doesn't block off half of it so I'm thinking there has to be a reason it is disabled above and beyond how often it gets used. Potential security and performance issues make sense if accurate.
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that comparison is crap, like "you dont need a nic since you dont use wol"
yes it may introduce potential security flaws, that was already covered. the bottom line though , is most dont use it, so its off, just like wol.
 
Bottom line seems to be, most don't use it, and if enabled and not used, there's more cons than pros so it's disabled. It's not merely because it's not used, otherwise a ton of stuff would be disabled. No need to get defensive, your answer isn't wrong, just incomplete.
 
WilyKit said:
Bottom line seems to be, most don't use it, and if enabled and not used, there's more cons than pros so it's disabled. It's not merely because it's not used, otherwise a ton of stuff would be disabled. No need to get defensive, your answer isn't wrong, just incomplete.
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Well tbh you COULD disable lots of bios options you probably don't use, you just don't.
 
WilyKit said:
There has to be more to it than that. 98% of users would also not make use of 32GB of ram if they had it, or a 4TB hard drive but the computer doesn't block off half of it so I'm thinking there has to be a reason it is disabled above and beyond how often it gets used. Potential security and performance issues make sense if accurate.
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Are you running virtual machines? If so - on. If not - off or whatever. For a while it defaulted to on, but folks found theoretical exploits, so now it defaults to off - there are some edge cases where there's a performance impact, but it's extremely minimal unless you're doing a ton of weird vector calcs and other AVX math (IIRC). It's on for all my systems - I run VMs.

It's an extremely minor change either way.
 
lopoetve said:
Are you running virtual machines? If so - on. If not - off or whatever. For a while it defaulted to on, but folks found theoretical exploits, so now it defaults to off - there are some edge cases where there's a performance impact, but it's extremely minimal unless you're doing a ton of weird vector calcs and other AVX math (IIRC). It's on for all my systems - I run VMs.

It's an extremely minor change either way.
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Yup same here...

Certainly I game... but for work there's a lot of virtualization. Which includes Hyper-V and Virtual Box. Especially for pen-testing.

I don't experience any meaningful performance decrease. Certainly there may be small differences in benchmarks. But in general use nothing at all.

In a specific scenario (Digital signal processing of radio waves- vector and FFT calcs) there is an actual difference in performance. The difference however is on the order of 1-2% based on my testing of a 3700x. Additionally, the demodulation, noise blanking, noise reduction, slicing, and conversion of digitized radio waves across 1Mhz of spectrum at 48k sample rate is fairly trivial for a modern processor. Some software uses the GPU for these tasks, making the CPU chug along relatively idle.

To give context, what I describe above is more or less a 100Mbit/s (12MB a second) stream of real time radio data.A trivial data rate- though the processing involved is less trivial.

Here is a video of this type of processing, plus multi layered decode, running on a AMD 9590 processor:

 
If anyone wants to use WSL2 to get a genuine Ubuntu terminal or something, then SVM must be turned on. Problem with turning it on is that anticheat for some games like Valorant will not allow you to play that game unless you turn SVM off.
 
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