linux-kernel - Re: [PATCH v3 00/24] KVM: TDX huge page support for private memory

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: <aV7Bpnbbf5qfXv1J@google.com>
Date: Wed, 7 Jan 2026 12:27:18 -0800
From: Sean Christopherson <seanjc@...gle.com>
To: Rick P Edgecombe <rick.p.edgecombe@...el.com>
Cc: "ackerleytng@...gle.com" <ackerleytng@...gle.com>, "kvm@...r.kernel.org" <kvm@...r.kernel.org>, 
	Fan Du <fan.du@...el.com>, Xiaoyao Li <xiaoyao.li@...el.com>, Kai Huang <kai.huang@...el.com>, 
	Dave Hansen <dave.hansen@...el.com>, Yan Y Zhao <yan.y.zhao@...el.com>, 
	"thomas.lendacky@....com" <thomas.lendacky@....com>, "vbabka@...e.cz" <vbabka@...e.cz>, 
	"tabba@...gle.com" <tabba@...gle.com>, "david@...nel.org" <david@...nel.org>, 
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>, "kas@...nel.org" <kas@...nel.org>, 
	Ira Weiny <ira.weiny@...el.com>, "pbonzini@...hat.com" <pbonzini@...hat.com>, 
	"binbin.wu@...ux.intel.com" <binbin.wu@...ux.intel.com>, Isaku Yamahata <isaku.yamahata@...el.com>, 
	"michael.roth@....com" <michael.roth@....com>, "nik.borisov@...e.com" <nik.borisov@...e.com>, 
	Chao P Peng <chao.p.peng@...el.com>, 
	"francescolavra.fl@...il.com" <francescolavra.fl@...il.com>, Vishal Annapurve <vannapurve@...gle.com>, 
	"sagis@...gle.com" <sagis@...gle.com>, Chao Gao <chao.gao@...el.com>, Jun Miao <jun.miao@...el.com>, 
	"jgross@...e.com" <jgross@...e.com>, "pgonda@...gle.com" <pgonda@...gle.com>, "x86@...nel.org" <x86@...nel.org>
Subject: Re: [PATCH v3 00/24] KVM: TDX huge page support for private memory

On Wed, Jan 07, 2026, Rick P Edgecombe wrote:
> On Tue, 2026-01-06 at 15:43 -0800, Sean Christopherson wrote:
> > Mapping a hugepage for memory that KVM _knows_ is contiguous and homogenous is
> > conceptually totally fine, i.e. I'm not totally opposed to adding support for
> > mapping multiple guest_memfd folios with a single hugepage.   As to whether we
> > do (a) nothing, (b) change the refcounting, or (c) add support for mapping
> > multiple folios in one page, probably comes down to which option provides "good
> > enough" performance without incurring too much complexity.
> 
> Can we add "whether we can push it off to the future" to the considerations
> list? The in-flight gmem stuff is pretty complex and this doesn't seem to have
> an ABI intersection.

Ya, for sure.  The only wrinkle I can think of is if the refcounting somehow
bleeds into userspace, but that seems like it'd be a flaw on its own.