From: David Laight <David.Laight@ACULAB.COM>
To: "'kirill.shutemov@linux.intel.com'"
<kirill.shutemov@linux.intel.com>,
"Huang, Kai" <kai.huang@intel.com>
Cc: "kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"Hansen, Dave" <dave.hansen@intel.com>,
"david@redhat.com" <david@redhat.com>,
"bagasdotme@gmail.com" <bagasdotme@gmail.com>,
"ak@linux.intel.com" <ak@linux.intel.com>,
"Wysocki, Rafael J" <rafael.j.wysocki@intel.com>,
"Luck, Tony" <tony.luck@intel.com>,
"Chatre, Reinette" <reinette.chatre@intel.com>, "Christopherson,,
Sean" <seanjc@google.com>,
"pbonzini@redhat.com" <pbonzini@redhat.com>,
"tglx@linutronix.de" <tglx@linutronix.de>,
"Yamahata, Isaku" <isaku.yamahata@intel.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
"Shahar, Sagi" <sagis@google.com>,
"peterz@infradead.org" <peterz@infradead.org>,
"imammedo@redhat.com" <imammedo@redhat.com>,
"Gao, Chao" <chao.gao@intel.com>,
"Brown, Len" <len.brown@intel.com>,
"sathyanarayanan.kuppuswamy@linux.intel.com"
<sathyanarayanan.kuppuswamy@linux.intel.com>,
"Huang, Ying" <ying.huang@intel.com>,
"Williams, Dan J" <dan.j.williams@intel.com>
Subject: RE: [PATCH v11 18/20] x86: Handle TDX erratum to reset TDX private memory during kexec() and reboot
Date: Mon, 12 Jun 2023 13:18:01 +0000 [thread overview]
Message-ID: <fc4930150f3242e69dcb007c0b23cfd2@AcuMS.aculab.com> (raw)
In-Reply-To: <20230612114843.n7vvoh7m2rk4la56@box.shutemov.name>
From: kirill.shutemov@linux.intel.com
> Sent: 12 June 2023 12:49
>
> On Mon, Jun 12, 2023 at 10:27:44AM +0000, Huang, Kai wrote:
> > Does it make sense?
>
> I understand your logic. AFAICS, it is correct (smp_mb() instead of __mb()
> would be better), but it is not justified from complexity PoV.
Given that x86 performs writes pretty much in code order.
Do you need anything more than a compile barrier?
> This lockless exercise gave me a pause to understand.
>
> Lockless doesn't buy you anything here, only increases complexity.
> Just take a lock.
Indeed...
David
-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
next prev parent reply other threads:[~2023-06-12 13:18 UTC|newest]
Thread overview: 174+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-04 14:27 [PATCH v11 00/20] TDX host kernel support Kai Huang
2023-06-04 14:27 ` [PATCH v11 01/20] x86/tdx: Define TDX supported page sizes as macros Kai Huang
2023-06-04 14:27 ` [PATCH v11 02/20] x86/virt/tdx: Detect TDX during kernel boot Kai Huang
2023-06-06 14:00 ` Sathyanarayanan Kuppuswamy
2023-06-06 22:58 ` Huang, Kai
2023-06-06 23:44 ` Isaku Yamahata
2023-06-19 12:12 ` David Hildenbrand
2023-06-19 23:58 ` Huang, Kai
2023-06-04 14:27 ` [PATCH v11 03/20] x86/virt/tdx: Make INTEL_TDX_HOST depend on X86_X2APIC Kai Huang
2023-06-08 0:08 ` kirill.shutemov
2023-06-04 14:27 ` [PATCH v11 04/20] x86/cpu: Detect TDX partial write machine check erratum Kai Huang
2023-06-06 12:38 ` kirill.shutemov
2023-06-06 22:58 ` Huang, Kai
2023-06-07 15:06 ` kirill.shutemov
2023-06-07 14:15 ` Dave Hansen
2023-06-07 22:43 ` Huang, Kai
2023-06-19 11:37 ` Huang, Kai
2023-06-20 15:44 ` Dave Hansen
2023-06-20 23:11 ` Huang, Kai
2023-06-19 12:21 ` David Hildenbrand
2023-06-20 10:31 ` Huang, Kai
2023-06-20 15:39 ` Dave Hansen
2023-06-20 16:03 ` David Hildenbrand
2023-06-20 16:21 ` Dave Hansen
2023-06-04 14:27 ` [PATCH v11 05/20] x86/virt/tdx: Add SEAMCALL infrastructure Kai Huang
2023-06-06 23:55 ` Isaku Yamahata
2023-06-07 14:24 ` Dave Hansen
2023-06-07 18:53 ` Isaku Yamahata
2023-06-07 19:27 ` Dave Hansen
2023-06-07 19:47 ` Isaku Yamahata
2023-06-07 20:08 ` Sean Christopherson
2023-06-07 20:22 ` Dave Hansen
2023-06-08 0:51 ` Huang, Kai
2023-06-08 13:50 ` Dave Hansen
2023-06-07 22:56 ` Huang, Kai
2023-06-08 14:05 ` Dave Hansen
2023-06-19 12:52 ` David Hildenbrand
2023-06-20 10:37 ` Huang, Kai
2023-06-20 12:20 ` kirill.shutemov
2023-06-20 12:39 ` David Hildenbrand
2023-06-20 15:15 ` Dave Hansen
2023-06-04 14:27 ` [PATCH v11 06/20] x86/virt/tdx: Handle SEAMCALL running out of entropy error Kai Huang
2023-06-07 8:19 ` Isaku Yamahata
2023-06-07 15:08 ` Dave Hansen
2023-06-07 23:36 ` Huang, Kai
2023-06-08 0:29 ` Dave Hansen
2023-06-08 0:08 ` kirill.shutemov
2023-06-09 14:42 ` Nikolay Borisov
2023-06-12 11:04 ` Huang, Kai
2023-06-19 13:00 ` David Hildenbrand
2023-06-20 10:39 ` Huang, Kai
2023-06-20 11:14 ` David Hildenbrand
2023-06-04 14:27 ` [PATCH v11 07/20] x86/virt/tdx: Add skeleton to enable TDX on demand Kai Huang
2023-06-05 21:23 ` Isaku Yamahata
2023-06-05 23:04 ` Huang, Kai
2023-06-05 23:08 ` Dave Hansen
2023-06-05 23:24 ` Huang, Kai
2023-06-07 15:22 ` Dave Hansen
2023-06-08 2:10 ` Huang, Kai
2023-06-08 13:43 ` Dave Hansen
2023-06-12 11:21 ` Huang, Kai
2023-06-19 13:16 ` David Hildenbrand
2023-06-19 23:28 ` Huang, Kai
2023-06-04 14:27 ` [PATCH v11 08/20] x86/virt/tdx: Get information about TDX module and TDX-capable memory Kai Huang
2023-06-07 15:25 ` Dave Hansen
2023-06-08 0:27 ` kirill.shutemov
2023-06-08 2:40 ` Huang, Kai
2023-06-08 11:41 ` kirill.shutemov
2023-06-08 13:13 ` Dave Hansen
2023-06-12 2:00 ` Huang, Kai
2023-06-08 23:29 ` Isaku Yamahata
2023-06-08 23:54 ` kirill.shutemov
2023-06-09 1:33 ` Isaku Yamahata
2023-06-09 10:02 ` kirill.shutemov
2023-06-12 2:00 ` Huang, Kai
2023-06-19 13:29 ` David Hildenbrand
2023-06-19 23:51 ` Huang, Kai
2023-06-04 14:27 ` [PATCH v11 09/20] x86/virt/tdx: Use all system memory when initializing TDX module as TDX memory Kai Huang
2023-06-07 15:48 ` Dave Hansen
2023-06-07 23:22 ` Huang, Kai
2023-06-08 22:40 ` kirill.shutemov
2023-06-04 14:27 ` [PATCH v11 10/20] x86/virt/tdx: Add placeholder to construct TDMRs to cover all TDX memory regions Kai Huang
2023-06-07 15:54 ` Dave Hansen
2023-06-07 15:57 ` Dave Hansen
2023-06-08 10:18 ` Huang, Kai
2023-06-08 22:52 ` kirill.shutemov
2023-06-12 2:21 ` Huang, Kai
2023-06-12 3:01 ` Dave Hansen
2023-06-04 14:27 ` [PATCH v11 11/20] x86/virt/tdx: Fill out " Kai Huang
2023-06-07 16:05 ` Dave Hansen
2023-06-08 10:48 ` Huang, Kai
2023-06-08 13:11 ` Dave Hansen
2023-06-12 2:33 ` Huang, Kai
2023-06-12 14:33 ` kirill.shutemov
2023-06-12 22:10 ` Huang, Kai
2023-06-13 10:18 ` kirill.shutemov
2023-06-13 23:19 ` Huang, Kai
2023-06-08 23:02 ` kirill.shutemov
2023-06-12 2:25 ` Huang, Kai
2023-06-09 4:01 ` Sathyanarayanan Kuppuswamy
2023-06-12 2:28 ` Huang, Kai
2023-06-14 12:31 ` Nikolay Borisov
2023-06-14 22:45 ` Huang, Kai
2023-06-04 14:27 ` [PATCH v11 12/20] x86/virt/tdx: Allocate and set up PAMTs for TDMRs Kai Huang
2023-06-08 23:24 ` kirill.shutemov
2023-06-08 23:43 ` Dave Hansen
2023-06-12 2:52 ` Huang, Kai
2023-06-25 15:38 ` Huang, Kai
2023-06-15 7:48 ` Nikolay Borisov
2023-06-04 14:27 ` [PATCH v11 13/20] x86/virt/tdx: Designate reserved areas for all TDMRs Kai Huang
2023-06-08 23:53 ` kirill.shutemov
2023-06-04 14:27 ` [PATCH v11 14/20] x86/virt/tdx: Configure TDX module with the TDMRs and global KeyID Kai Huang
2023-06-08 23:53 ` kirill.shutemov
2023-06-04 14:27 ` [PATCH v11 15/20] x86/virt/tdx: Configure global KeyID on all packages Kai Huang
2023-06-08 23:53 ` kirill.shutemov
2023-06-15 8:12 ` Nikolay Borisov
2023-06-15 22:24 ` Huang, Kai
2023-06-19 14:56 ` kirill.shutemov
2023-06-19 23:38 ` Huang, Kai
2023-06-04 14:27 ` [PATCH v11 16/20] x86/virt/tdx: Initialize all TDMRs Kai Huang
2023-06-09 10:03 ` kirill.shutemov
2023-06-04 14:27 ` [PATCH v11 17/20] x86/kexec: Flush cache of TDX private memory Kai Huang
2023-06-09 10:14 ` kirill.shutemov
2023-06-04 14:27 ` [PATCH v11 18/20] x86: Handle TDX erratum to reset TDX private memory during kexec() and reboot Kai Huang
2023-06-09 13:23 ` kirill.shutemov
2023-06-12 3:06 ` Huang, Kai
2023-06-12 7:58 ` kirill.shutemov
2023-06-12 10:27 ` Huang, Kai
2023-06-12 11:48 ` kirill.shutemov
2023-06-12 13:18 ` David Laight [this message]
2023-06-12 13:47 ` Dave Hansen
2023-06-13 0:51 ` Huang, Kai
2023-06-13 11:05 ` kirill.shutemov
2023-06-14 0:15 ` Huang, Kai
2023-06-13 14:25 ` Dave Hansen
2023-06-13 23:18 ` Huang, Kai
2023-06-14 0:24 ` Dave Hansen
2023-06-14 0:38 ` Huang, Kai
2023-06-14 0:42 ` Huang, Kai
2023-06-19 11:43 ` Huang, Kai
2023-06-19 14:31 ` Dave Hansen
2023-06-19 14:46 ` kirill.shutemov
2023-06-19 23:35 ` Huang, Kai
2023-06-19 23:41 ` Dave Hansen
2023-06-20 0:56 ` Huang, Kai
2023-06-20 1:06 ` Dave Hansen
2023-06-20 7:58 ` Peter Zijlstra
2023-06-25 15:30 ` Huang, Kai
2023-06-25 23:26 ` Huang, Kai
2023-06-20 7:48 ` Peter Zijlstra
2023-06-20 8:11 ` Peter Zijlstra
2023-06-20 10:42 ` Huang, Kai
2023-06-20 10:56 ` Peter Zijlstra
2023-06-14 9:33 ` Huang, Kai
2023-06-14 10:02 ` kirill.shutemov
2023-06-14 10:58 ` Huang, Kai
2023-06-14 11:08 ` kirill.shutemov
2023-06-14 11:17 ` Huang, Kai
2023-06-04 14:27 ` [PATCH v11 19/20] x86/mce: Improve error log of kernel space TDX #MC due to erratum Kai Huang
2023-06-05 2:13 ` Xiaoyao Li
2023-06-05 23:05 ` Huang, Kai
2023-06-09 13:17 ` kirill.shutemov
2023-06-12 3:08 ` Huang, Kai
2023-06-12 7:59 ` kirill.shutemov
2023-06-12 13:51 ` Dave Hansen
2023-06-12 23:31 ` Huang, Kai
2023-06-04 14:27 ` [PATCH v11 20/20] Documentation/x86: Add documentation for TDX host support Kai Huang
2023-06-08 23:56 ` Dave Hansen
2023-06-12 3:41 ` Huang, Kai
2023-06-16 9:02 ` Nikolay Borisov
2023-06-16 16:26 ` Dave Hansen
2023-06-06 0:36 ` [PATCH v11 00/20] TDX host kernel support Isaku Yamahata
2023-06-08 21:03 ` Dan Williams
2023-06-12 10:56 ` Huang, Kai
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