linux-kernel - Re: [RFC PATCH v5 04/45] KVM: x86: Make "external SPTE" ops that can fail RET0 static calls

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Message-ID: <f9f65b0fad57db12e21d2168d02bac036615fb7f.camel@intel.com>
Date: Thu, 29 Jan 2026 22:20:18 +0000
From: "Edgecombe, Rick P" <rick.p.edgecombe@...el.com>
To: "seanjc@...gle.com" <seanjc@...gle.com>, "x86@...nel.org"
	<x86@...nel.org>, "dave.hansen@...ux.intel.com"
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CC: "Huang, Kai" <kai.huang@...el.com>, "ackerleytng@...gle.com"
	<ackerleytng@...gle.com>, "sagis@...gle.com" <sagis@...gle.com>, "Annapurve,
 Vishal" <vannapurve@...gle.com>, "linux-kernel@...r.kernel.org"
	<linux-kernel@...r.kernel.org>, "Zhao, Yan Y" <yan.y.zhao@...el.com>, "Li,
 Xiaoyao" <xiaoyao.li@...el.com>, "kvm@...r.kernel.org" <kvm@...r.kernel.org>,
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	<binbin.wu@...ux.intel.com>
Subject: Re: [RFC PATCH v5 04/45] KVM: x86: Make "external SPTE" ops that can
 fail RET0 static calls

On Wed, 2026-01-28 at 17:14 -0800, Sean Christopherson wrote:
> Define kvm_x86_ops .link_external_spt(), .set_external_spte(), and
> .free_external_spt() as RET0 static calls so that an unexpected call to a
> a default operation doesn't consume garbage.
> 
> Fixes: 77ac7079e66d ("KVM: x86/tdp_mmu: Propagate building mirror page tables")
> Fixes: 94faba8999b9 ("KVM: x86/tdp_mmu: Propagate tearing down mirror page tables")
> Signed-off-by: Sean Christopherson <seanjc@...gle.com>

We don't want to crash unnecessarily, but do we want to get some sort of notice?