How to shut down a specified CPU instruction set in a virtual machine?

postchen

New Member
Mar 25, 2024
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How to shut down a specified CPU instruction set in a virtual machine?
For example, what should I do if I need to block the vt-x instruction set of the CPU?
 
For example, what should I do if I need to block the vt-x instruction set of the CPU?
Maybe disable nested virtualization, like doing the opposite of this: https://pve.proxmox.com/wiki/Nested_Virtualization ?
Maybe choosing a generic CPU Type like x86-64 or kvm64 (instead of host or max) also does not provide nested virtualization?
You could try a feature request for a nested virtualization toggle, as it seems like a useful addition to the other CPU toggles that Proxmox already supports in the web GUI.

You can specify a custom CPU Type in Proxmox (but I have no experience with that myself): https://pve.proxmox.com/pve-docs/pve-admin-guide.html#_custom_cpu_types
 
Maybe disable nested virtualization, like doing the opposite of this: https://pve.proxmox.com/wiki/Nested_Virtualization ?
Maybe choosing a generic CPU Type like x86-64 or kvm64 (instead of host or max) also does not provide nested virtualization?
You could try a feature request for a nested virtualization toggle, as it seems like a useful addition to the other CPU toggles that Proxmox already supports in the web GUI.

You can specify a custom CPU Type in Proxmox (but I have no experience with that myself): https://pve.proxmox.com/pve-docs/pve-admin-guide.html#_custom_cpu_types
Due to the use of host for CPU type, blue screen may occur
By using other methods, this issue would not occur. After comparing the instruction sets, we found that the host has an additional vt-x instruction set, but we still want to use hots, so we want to block it. We want to test if this instruction set is causing blue screens.
 
By using other methods, this issue would not occur. After comparing the instruction sets, we found that the host has an additional vt-x instruction set, but we still want to use hots, so we want to block it. We want to test if this instruction set is causing blue screens.
Try cpu: host,flags=-vmx or args: -cpu host,-vmx or create your own custom CPU type.
 

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