Re: [PATCH 1/1] kvm: increase max vcpu count

From: Radim KrÄmÃÅ
Date: Thu May 15 2014 - 06:23:31 EST


2014-05-15 17:50+0800, Li, Zhen-Hua:
> This patch is trying to increase the maximum supported vcpu number.
>
> There has been big system supporting more than 256 logical CPUs, and vmware
> can also support guest system with more than logical 256 CPUs. So kvm should
> also increase the maximum supported cpu number.

How did it work?
KVM lapic does not handle more more than 256 [1] at the moment, so
additional VCPUs had to wraparound ...

---
1: "struct kvm_apic_map" has "struct kvm_lapic *phys_map[256]" and we
are using "& 0xff" when dealing with it, too.
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