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From: Dave Hansen <dave.hansen@intel.com>
To: "Edgecombe, Rick P" <rick.p.edgecombe@intel.com>,
	"nik.borisov@suse.com" <nik.borisov@suse.com>,
	"kas@kernel.org" <kas@kernel.org>
Cc: "kvm@vger.kernel.org" <kvm@vger.kernel.org>,
	"linux-coco@lists.linux.dev" <linux-coco@lists.linux.dev>,
	"Huang, Kai" <kai.huang@intel.com>,
	"Li, Xiaoyao" <xiaoyao.li@intel.com>,
	"Zhao, Yan Y" <yan.y.zhao@intel.com>,
	"Wu, Binbin" <binbin.wu@intel.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"seanjc@google.com" <seanjc@google.com>,
	"mingo@redhat.com" <mingo@redhat.com>,
	"pbonzini@redhat.com" <pbonzini@redhat.com>,
	"tglx@linutronix.de" <tglx@linutronix.de>,
	"Yamahata, Isaku" <isaku.yamahata@intel.com>,
	"Annapurve, Vishal" <vannapurve@google.com>,
	"Gao, Chao" <chao.gao@intel.com>, "bp@alien8.de" <bp@alien8.de>,
	"x86@kernel.org" <x86@kernel.org>
Subject: Re: [PATCH v4 07/16] x86/virt/tdx: Add tdx_alloc/free_page() helpers
Date: Wed, 3 Dec 2025 10:21:37 -0800	[thread overview]
Message-ID: <474f5ace-e237-4c01-b0bc-d3e68ecc937b@intel.com> (raw)
In-Reply-To: <bb174006cbe969fc71fe71a3e12003ab9052213c.camel@intel.com>

On 12/3/25 10:15, Edgecombe, Rick P wrote:
> On Wed, 2025-12-03 at 07:41 -0800, Dave Hansen wrote:
>> It's fixed at a "page pair" in the ABI documentation, no?
>>
>> If Intel wants anything else, it should have documented that as the ABI.
>> So, as far as the code goes, it's a "page pair" now and forever. Linux
>> does not need to go out of its way to make it inflexible, but there's no
>> need to add complexity now for some future that may never come.
>>
>> I agree with Nikolay: KISS.
> Thanks Dave. Yes, let's stick to the spec. I'm going to try to pull the loops
> out too because we can get rid of the union array thing too.

Also, I honestly don't see the problem with just allocating an order-1
page for this. Yeah, the TDX modules doesn't need physically contiguous
pages, but it's easier for _us_ to lug them around if they are
physically contiguous.

Plus, if you permanently allocate 2 order-0 pages, you are _probably_
going to permanently destroy 2 potential future 2MB pages. The order-1
allocation will only destroy 1.



  reply	other threads:[~2025-12-03 18:21 UTC|newest]

Thread overview: 106+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-11-21  0:51 [PATCH v4 00/16] TDX: Enable Dynamic PAMT Rick Edgecombe
2025-11-21  0:51 ` [PATCH v4 01/16] x86/tdx: Move all TDX error defines into <asm/shared/tdx_errno.h> Rick Edgecombe
2025-11-25 22:30   ` Huang, Kai
2025-11-25 22:44     ` Huang, Kai
2025-11-26 23:15       ` Edgecombe, Rick P
2025-11-26 23:14     ` Edgecombe, Rick P
2025-11-21  0:51 ` [PATCH v4 02/16] x86/tdx: Add helpers to check return status codes Rick Edgecombe
2025-11-24  8:56   ` Binbin Wu
2025-11-24 19:31     ` Edgecombe, Rick P
2025-11-25 23:07   ` Huang, Kai
2025-11-26 23:26     ` Edgecombe, Rick P
2025-11-21  0:51 ` [PATCH v4 03/16] x86/virt/tdx: Simplify tdmr_get_pamt_sz() Rick Edgecombe
2025-11-24  9:26   ` Binbin Wu
2025-11-24 19:47     ` Edgecombe, Rick P
2025-11-25  1:27       ` Binbin Wu
2025-11-21  0:51 ` [PATCH v4 04/16] x86/virt/tdx: Allocate page bitmap for Dynamic PAMT Rick Edgecombe
2025-11-25  1:50   ` Binbin Wu
2025-11-26 17:56     ` Edgecombe, Rick P
2025-12-24  9:10   ` Xu Yilun
2026-01-05 22:06     ` Edgecombe, Rick P
2026-01-06  4:01       ` Xu Yilun
2026-01-06 17:00         ` Edgecombe, Rick P
2026-01-07  6:01           ` Xu Yilun
2026-01-07 14:41             ` Edgecombe, Rick P
2026-01-08 12:53               ` Xu Yilun
2026-01-08 16:52                 ` Edgecombe, Rick P
2026-01-09  2:18                   ` Xu Yilun
2026-01-09 16:05                     ` Edgecombe, Rick P
2026-01-12  0:24                       ` Xu Yilun
2025-11-21  0:51 ` [PATCH v4 05/16] x86/virt/tdx: Allocate reference counters for PAMT memory Rick Edgecombe
2025-11-21  0:51 ` [PATCH v4 06/16] x86/virt/tdx: Improve PAMT refcounts allocation for sparse memory Rick Edgecombe
2025-11-25  3:15   ` Binbin Wu
2025-11-26 20:47     ` Edgecombe, Rick P
2025-11-27 15:57       ` Kiryl Shutsemau
2025-12-01 22:14         ` Edgecombe, Rick P
2025-11-26 14:45   ` Nikolay Borisov
2025-11-26 20:47     ` Edgecombe, Rick P
2025-11-27  7:36       ` Nikolay Borisov
2025-12-11  0:07         ` Edgecombe, Rick P
2025-11-27 16:04       ` Kiryl Shutsemau
2025-11-21  0:51 ` [PATCH v4 07/16] x86/virt/tdx: Add tdx_alloc/free_page() helpers Rick Edgecombe
2025-11-25  8:09   ` Binbin Wu
2025-11-26 22:28     ` Edgecombe, Rick P
2026-01-29  1:19       ` Sean Christopherson
2026-01-29 17:18         ` Edgecombe, Rick P
2026-01-29 19:09           ` Sean Christopherson
2026-01-29 19:12             ` Edgecombe, Rick P
2025-11-26  1:21   ` Huang, Kai
2025-11-26 22:28     ` Edgecombe, Rick P
2025-11-27 12:29   ` Nikolay Borisov
2025-12-01 22:31     ` Edgecombe, Rick P
2025-11-27 16:11   ` Nikolay Borisov
2025-12-01 22:39     ` Edgecombe, Rick P
2025-12-02  7:38       ` Nikolay Borisov
2025-12-02 20:02         ` Edgecombe, Rick P
2025-12-03 13:46           ` Kiryl Shutsemau
2025-12-03 13:48             ` Nikolay Borisov
2025-12-03 15:41               ` Dave Hansen
2025-12-03 18:15                 ` Edgecombe, Rick P
2025-12-03 18:21                   ` Dave Hansen [this message]
2025-12-03 19:59                     ` Edgecombe, Rick P
2025-12-03 20:13                       ` Dave Hansen
2025-12-03 21:39                         ` Edgecombe, Rick P
2025-12-03 21:40                           ` Dave Hansen
2025-12-08  9:15   ` Yan Zhao
2025-12-08 20:27     ` Edgecombe, Rick P
2026-01-16 23:17   ` Sean Christopherson
2026-01-16 23:25     ` Edgecombe, Rick P
2026-01-16 23:40     ` Dave Hansen
2025-11-21  0:51 ` [PATCH v4 08/16] x86/virt/tdx: Optimize " Rick Edgecombe
2025-11-21  0:51 ` [PATCH v4 09/16] KVM: TDX: Allocate PAMT memory for TD control structures Rick Edgecombe
2025-11-25  9:11   ` Binbin Wu
2025-11-21  0:51 ` [PATCH v4 10/16] KVM: TDX: Allocate PAMT memory for vCPU " Rick Edgecombe
2025-11-25  9:14   ` Binbin Wu
2025-11-21  0:51 ` [PATCH v4 11/16] KVM: TDX: Add x86 ops for external spt cache Rick Edgecombe
2026-01-17  0:53   ` Sean Christopherson
2026-01-19  2:31     ` Yan Zhao
2026-01-20  8:42       ` Huang, Kai
2026-01-20  9:18         ` Yan Zhao
2026-01-20 10:00           ` Huang, Kai
2026-01-20 19:53     ` Edgecombe, Rick P
2026-01-21 22:12       ` Sean Christopherson
2026-01-21 22:34         ` Edgecombe, Rick P
2025-11-21  0:51 ` [PATCH v4 12/16] x86/virt/tdx: Add helpers to allow for pre-allocating pages Rick Edgecombe
2025-11-26  3:40   ` Binbin Wu
2025-11-26  5:21     ` Binbin Wu
2025-11-26 22:33     ` Edgecombe, Rick P
2025-11-27  2:38       ` Binbin Wu
2026-01-20  7:10         ` Huang, Kai
2026-01-20  7:46           ` Yan Zhao
2026-01-20  8:01             ` Huang, Kai
2026-01-17  1:02   ` Sean Christopherson
2026-01-21  0:52   ` Sean Christopherson
2026-01-21  0:58     ` Edgecombe, Rick P
2025-11-21  0:51 ` [PATCH v4 13/16] KVM: TDX: Handle PAMT allocation in fault path Rick Edgecombe
2025-11-26  5:56   ` Binbin Wu
2025-11-26 22:33     ` Edgecombe, Rick P
2025-11-21  0:51 ` [PATCH v4 14/16] KVM: TDX: Reclaim PAMT memory Rick Edgecombe
2025-11-26  8:53   ` Binbin Wu
2025-11-26 22:58     ` Edgecombe, Rick P
2025-11-21  0:51 ` [PATCH v4 15/16] x86/virt/tdx: Enable Dynamic PAMT Rick Edgecombe
2025-11-21  0:51 ` [PATCH v4 16/16] Documentation/x86: Add documentation for TDX's " Rick Edgecombe
2025-11-26 10:33   ` Binbin Wu
2025-11-26 20:05     ` Edgecombe, Rick P
2025-11-24 20:18 ` [PATCH v4 00/16] TDX: Enable " Sagi Shahar
2025-11-25 20:19 ` Vishal Annapurve

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