linux-kernel - Re: [PATCH] KVM: VMX: Reject KVM_RUN if userspace forces emulation during nested VM-Enter

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Message-ID: <174076295226.3737514.12262094016523053976.b4-ty@google.com>
Date: Fri, 28 Feb 2025 15:40:34 -0800
From: Sean Christopherson <seanjc@...gle.com>
To: Sean Christopherson <seanjc@...gle.com>, Paolo Bonzini <pbonzini@...hat.com>
Cc: kvm@...r.kernel.org, linux-kernel@...r.kernel.org, 
	syzbot+ac0bc3a70282b4d586cc@...kaller.appspotmail.com, 
	James Houghton <jthoughton@...gle.com>
Subject: Re: [PATCH] KVM: VMX: Reject KVM_RUN if userspace forces emulation
 during nested VM-Enter

On Mon, 24 Feb 2025 09:14:09 -0800, Sean Christopherson wrote:
> Extend KVM's restrictions on userspace forcing "emulation required" at odd
> times to cover stuffing invalid guest state while a nested run is pending.
> Clobbering guest state while KVM is in the middle of emulating VM-Enter is
> nonsensical, as it puts the vCPU into an architecturally impossible state,
> and will trip KVM's sanity check that guards against KVM bugs, e.g. helps
> detect missed VMX consistency checks.
> 
> [...]

Applied to kvm-x86 vmx, thanks!

[1/1] KVM: VMX: Reject KVM_RUN if userspace forces emulation during nested VM-Enter
      https://github.com/kvm-x86/linux/commit/64c947a1cf35

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https://github.com/kvm-x86/linux/tree/next