linux-kernel - Re: [RFC PATCH v5 09/45] KVM: x86: Rework .free_external_spt() into .reclaim_external

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Message-ID: <aYUb0KvJynvYjr3h@google.com>
Date: Thu, 5 Feb 2026 14:38:08 -0800
From: Sean Christopherson <seanjc@...gle.com>
To: Yan Zhao <yan.y.zhao@...el.com>
Cc: Thomas Gleixner <tglx@...nel.org>, Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>, 
	Dave Hansen <dave.hansen@...ux.intel.com>, x86@...nel.org, 
	Kiryl Shutsemau <kas@...nel.org>, Paolo Bonzini <pbonzini@...hat.com>, linux-kernel@...r.kernel.org, 
	linux-coco@...ts.linux.dev, kvm@...r.kernel.org, 
	Kai Huang <kai.huang@...el.com>, Rick Edgecombe <rick.p.edgecombe@...el.com>, 
	Vishal Annapurve <vannapurve@...gle.com>, Ackerley Tng <ackerleytng@...gle.com>, 
	Sagi Shahar <sagis@...gle.com>, Binbin Wu <binbin.wu@...ux.intel.com>, 
	Xiaoyao Li <xiaoyao.li@...el.com>, Isaku Yamahata <isaku.yamahata@...el.com>
Subject: Re: [RFC PATCH v5 09/45] KVM: x86: Rework .free_external_spt() into .reclaim_external_sp()

On Thu, Feb 05, 2026, Yan Zhao wrote:
> On Wed, Feb 04, 2026 at 05:45:39PM +0800, Yan Zhao wrote:
> > On Wed, Jan 28, 2026 at 05:14:41PM -0800, Sean Christopherson wrote:
> > > diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
> > > index d12ca0f8a348..b35a07ed11fb 100644
> > > --- a/arch/x86/include/asm/kvm_host.h
> > > +++ b/arch/x86/include/asm/kvm_host.h
> > > @@ -1858,8 +1858,8 @@ struct kvm_x86_ops {
> > >  				 u64 mirror_spte);
> > >  
> > >  	/* Update external page tables for page table about to be freed. */
> > > -	int (*free_external_spt)(struct kvm *kvm, gfn_t gfn, enum pg_level level,
> > > -				 void *external_spt);
> > > +	void (*reclaim_external_sp)(struct kvm *kvm, gfn_t gfn,
> > > +				    struct kvm_mmu_page *sp);
> > Do you think "free" is still better than "reclaim" though TDX actually
> > invokes tdx_reclaim_page() to reclaim it on the TDX side?
> > 
> > Naming it free_external_sp can be interpreted as freeing the sp->external_spt
> > externally (vs freeing it in tdp_mmu_free_sp_rcu_callback(). This naming also
> > allows for the future possibility of freeing sp->external_spt before the HKID is
> > freed (though this is unlikely).
> Oh. I found there's a free_external_sp() in patch 20.
> 
> So, maybe reclaim_external_sp() --> remove_external_spt() ?
> 
> Still think "sp" is not good :)

I think my vote would be for reclaim_external_spt().  I don't like "remove", because
similar to "free", I think most readers will assume success is guaranteed.