linux-kernel - Re: [PATCH RFC v1 07/20] KVM: nVMX: Support the extended instruction info field

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Message-ID: <43f74a56-e56d-49b6-9652-f46f648b53e1@intel.com>
Date: Thu, 13 Nov 2025 15:21:15 -0800
From: "Chang S. Bae" <chang.seok.bae@...el.com>
To: Chao Gao <chao.gao@...el.com>, Paolo Bonzini <pbonzini@...hat.com>
CC: <kvm@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	<seanjc@...gle.com>, <zhao1.liu@...el.com>
Subject: Re: [PATCH RFC v1 07/20] KVM: nVMX: Support the extended instruction
 info field

On 11/11/2025 5:54 PM, Chao Gao wrote:
> 
> Shouldn't we check guest's capabilities rather than host's,
> 
> i.e., guest_cpu_cap_has(X86_FEATURE_APX)?

Perhaps adding a comment like this would help clarify it:

   /*
    * The APX enumeration guarantees the presence of the extended
    * field. The host CPUID bit alone is sufficient to rely on it.
    */
   static inline bool vmx_ext_insn_info_available(void) {
	return static_cpu_has(X86_FEATURE_APX);
   }