linux-kernel - Re: [RFC PATCH v5 20/45] KVM: x86/mmu: Allocate/free S-EPT pages using tdx_{alloc,free}_control

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <9f2c5b3a3b72436c0b3c44fadaa2c9a8548de191.camel@intel.com>
Date: Tue, 3 Feb 2026 21:18:50 +0000
From: "Huang, Kai" <kai.huang@...el.com>
To: "seanjc@...gle.com" <seanjc@...gle.com>
CC: "kvm@...r.kernel.org" <kvm@...r.kernel.org>, "linux-coco@...ts.linux.dev"
	<linux-coco@...ts.linux.dev>, "Li, Xiaoyao" <xiaoyao.li@...el.com>, "Zhao,
 Yan Y" <yan.y.zhao@...el.com>, "dave.hansen@...ux.intel.com"
	<dave.hansen@...ux.intel.com>, "kas@...nel.org" <kas@...nel.org>,
	"mingo@...hat.com" <mingo@...hat.com>, "binbin.wu@...ux.intel.com"
	<binbin.wu@...ux.intel.com>, "pbonzini@...hat.com" <pbonzini@...hat.com>,
	"ackerleytng@...gle.com" <ackerleytng@...gle.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>, "Yamahata,
 Isaku" <isaku.yamahata@...el.com>, "sagis@...gle.com" <sagis@...gle.com>,
	"tglx@...nel.org" <tglx@...nel.org>, "Edgecombe, Rick P"
	<rick.p.edgecombe@...el.com>, "bp@...en8.de" <bp@...en8.de>, "Annapurve,
 Vishal" <vannapurve@...gle.com>, "x86@...nel.org" <x86@...nel.org>
Subject: Re: [RFC PATCH v5 20/45] KVM: x86/mmu: Allocate/free S-EPT pages
 using tdx_{alloc,free}_control_page()

On Tue, 2026-02-03 at 12:17 -0800, Sean Christopherson wrote:
> On Tue, Feb 03, 2026, Kai Huang wrote:
> > On Wed, 2026-01-28 at 17:14 -0800, Sean Christopherson wrote:
> > >   	int (*set_external_spte)(struct kvm *kvm, gfn_t gfn, enum pg_level level,
> > >   				 u64 mirror_spte);
> > > -
> > > -	/* Update external page tables for page table about to be freed. */
> > >   	void (*reclaim_external_sp)(struct kvm *kvm, gfn_t gfn,
> > >   				    struct kvm_mmu_page *sp);
> > > -
> > > -	/* Update external page table from spte getting removed, and flush TLB. */
> > 
> > The above two comments are still useful to me.
> > 
> > Not sure why do you want to remove them, especially in _this_ patch?
> 
> My intent was to replace the individual comments with a more generic comment for
> all of the "external" hooks.  For things like "and flush TLB", IMO those comments
> belong at the call sites, not at this point.  E.g. _KVM_ doesn't require a TLB
> flush in all cases.  And so for the definition of the hooks, I would prefer a more
> generic comment, so that if there are details that matter to the usage, they are
> documented there.

I see.  You actually mentioned "propagate changes in mirror page tables to
the external pages" in the new comment, so all make sense to me now.