Re: kconfig does not accept a lower value for KVM_MAX_NR_VCPUS

Bagas Sanjaya
2025-01-19T23:55:43Z

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On Sun, Jan 19, 2025 at 12:04:04PM +0100, Toralf Förster wrote:
> I was wondering why I cannot put a lower value here during make oldconfig:
>
>
> Maximum number of vCPUs per KVM guest (KVM_MAX_NR_VCPUS) [1024] (NEW) 16
> Maximum number of vCPUs per KVM guest (KVM_MAX_NR_VCPUS) [1024] (NEW) 8
> Maximum number of vCPUs per KVM guest (KVM_MAX_NR_VCPUS) [1024] (NEW)
>

Hi Toralf,

From arch/x86/kvm/Kconfig:

>config KVM_MAX_NR_VCPUS
> int "Maximum number of vCPUs per KVM guest"
> depends on KVM
> range 1024 4096
> default 4096 if MAXSMP
> default 1024
> help
> Set the maximum number of vCPUs per KVM guest. Larger values will increase
> the memory footprint of each KVM guest, regardless of how many vCPUs are
> created for a given VM.

I don't know your use case, but you can safely choose the default (1024).

Thanks.

--
An old man doll... just what I always wanted! - Clara

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