Re: [PATCH] KVM: x86: Disallow setting CPUID and/or feature MSRs if L2 is active

Sean Christopherson
2026-01-12T17:40:07Z

On Tue, 30 Dec 2025 12:56:41 -0800, Sean Christopherson wrote:
> Extend KVM's restriction on CPUID and feature MSR changes to disallow
> updates while L2 is active in addition to rejecting updates after the vCPU
> has run at least once. Like post-run vCPU model updates, attempting to
> react to model changes while L2 is active is practically infeasible, e.g.
> KVM would need to do _something_ in response to impossible situations where
> userspace has a removed a feature that was consumed as parted of nested
> VM-Enter.
>
> [...]

Applied to kvm-x86 misc, thanks!

[1/1] KVM: x86: Disallow setting CPUID and/or feature MSRs if L2 is active
https://github.com/kvm-x86/linux/commit/b47b93c15b12

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