KVM parameters to optimize Hyper-V with AMD processors

[vic]

@lI_Simo_Hayha_Il

The only setting that allows me to play actually, is this

<feature policy="disable" name="hypervisor"/>

and then install Hyper-V under Windows. That alone, makes PUBG run. However, when I do that, performance in PUBG is worse, BF2042 also, and other games are unplayable.

This ‘hypervisor’ flag caught my attention. For the past few years, I’ve always had this flag turned on for all VMs. I just realized disabling it for Windows 11 guest improves all-core performance by 1.5-2%. The effect of this flag is consistently reproducible for me. Puzzling me but interesting re-discovery.

@lI_Simo_Hayha_Il

I was making changes bit-by-bit to find out which parameter causes the reset and I found it:

<feature policy="require" name="x2apic"/>

So, after removing this line, no more resets, and I could play and run benchmarks.

The effect of this flag should be minimal if number of virtual cores is fewer than 32. If you find it helpful, it helps then. I always find it tedious to deal these flags with minimal documentation.

@lI_Simo_Hayha_Il

to this

<feature policy="disable" name="svm"/>

My performance was back!!!

I’m quite sure this flag is irrelevant to the performance of the immediate guest. One possible way it might have helped you because you accidentally enabled Hyper-V in your Windows installation, which you shouldn’t have enabled.