linux-kernel - Re: [PATCH v3] KVM: SVM: Don't allow L1 intercepts for instructions not advertised

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Message-ID: <176823877360.1368641.767900599632930102.b4-ty@google.com>
Date: Mon, 12 Jan 2026 09:38:54 -0800
From: Sean Christopherson <seanjc@...gle.com>
To: Sean Christopherson <seanjc@...gle.com>, pbonzini@...hat.com, 
	Kevin Cheng <chengkev@...gle.com>
Cc: jmattson@...gle.com, yosry.ahmed@...ux.dev, kvm@...r.kernel.org, 
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3] KVM: SVM: Don't allow L1 intercepts for instructions
 not advertised

On Mon, 15 Dec 2025 19:25:10 +0000, Kevin Cheng wrote:
> If a feature is not advertised in the guest's CPUID, prevent L1 from
> intercepting the unsupported instructions by clearing the corresponding
> intercept in KVM's cached vmcb12.
> 
> When an L2 guest executes an instruction that is not advertised to L1,
> we expect a #UD exception to be injected by L0. However, the nested svm
> exit handler first checks if the instruction intercept is set in vmcb12,
> and if so, synthesizes an exit from L2 to L1 instead of a #UD exception.
> If a feature is not advertised, the L1 intercept should be ignored.
> 
> [...]

Applied to kvm-x86 svm, thanks!

[1/1] KVM: SVM: Don't allow L1 intercepts for instructions not advertised
      https://github.com/kvm-x86/linux/commit/1d1722e52fcd

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