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From: Tom Lendacky <thomas.lendacky@amd.com>
To: Rik van Riel <riel@surriel.com>, Borislav Petkov <bp@alien8.de>
Cc: x86@kernel.org, linux-kernel@vger.kernel.org,
	peterz@infradead.org, dave.hansen@linux.intel.com,
	zhengqi.arch@bytedance.com, nadav.amit@gmail.com,
	kernel-team@meta.com, linux-mm@kvack.org,
	akpm@linux-foundation.org, jackmanb@google.com, jannh@google.com,
	mhklinux@outlook.com, andrew.cooper3@citrix.com,
	Manali.Shukla@amd.com, mingo@kernel.org
Subject: Re: [PATCH v13 06/14] x86/mm: use broadcast TLB flushing for page reclaim TLB flushing
Date: Wed, 26 Feb 2025 11:36:23 -0600	[thread overview]
Message-ID: <059ba03a-a892-6a68-6000-c7db3dd6cf9c@amd.com> (raw)
In-Reply-To: <297b28e9ef9f4cd983ae2e3dd4cf1fce8b74d0f1.camel@surriel.com>

On 2/26/25 11:02, Rik van Riel wrote:
> On Wed, 2025-02-26 at 11:00 -0600, Tom Lendacky wrote:
>> On 2/25/25 15:03, Borislav Petkov wrote:
>>> On Tue, Feb 25, 2025 at 09:38:03PM +0100, Borislav Petkov wrote:
>>>> On Tue, Feb 25, 2025 at 02:17:20PM -0500, Rik van Riel wrote:
>>>>> Who do we need to ask to confirm that reading?
>>>>
>>>> Lemme figure it out.
>>>
>>> Confirmed - that really is the case.
>>
>> Hmmm... since this is for host/hypervisor TLB handling, this makes me
>> think that we should always be setting the ASID valid bit with 0 for
>> the
>> ASID value in EDX[15:0] on all INVLPGB instructions in this series.
>> Otherwise we will also be flushing any guest ASID TLB entries that
>> match
>> the conditions, when that isn't intended.
> 
> The ASID is always zero in this series.
> 
> We only ever use the PCID for address space identification.

Right, but the ASID valid bit is not set, so the flushing may match more
than just host/hypervisor TLB entries.

Thanks,
Tom

> 


  reply	other threads:[~2025-02-26 17:36 UTC|newest]

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-02-23 19:48 [PATCH v13 00/14] AMD broadcast TLB invalidation Rik van Riel
2025-02-23 19:48 ` [PATCH v13 01/14] x86/mm: consolidate full flush threshold decision Rik van Riel
2025-02-24 11:48   ` Borislav Petkov
2025-02-23 19:48 ` [PATCH v13 02/14] x86/mm: get INVLPGB count max from CPUID Rik van Riel
2025-02-24 12:00   ` Borislav Petkov
2025-02-23 19:48 ` [PATCH v13 03/14] x86/mm: add INVLPGB support code Rik van Riel
2025-02-24 12:14   ` Borislav Petkov
2025-02-23 19:48 ` [PATCH v13 04/14] x86/mm: use INVLPGB for kernel TLB flushes Rik van Riel
2025-02-24 12:31   ` Borislav Petkov
2025-02-24 12:44     ` Nadav Amit
2025-02-23 19:48 ` [PATCH v13 05/14] x86/mm: use INVLPGB in flush_tlb_all Rik van Riel
2025-02-24 12:46   ` Borislav Petkov
2025-02-23 19:48 ` [PATCH v13 06/14] x86/mm: use broadcast TLB flushing for page reclaim TLB flushing Rik van Riel
2025-02-24 13:27   ` Borislav Petkov
2025-02-25 19:17     ` Rik van Riel
2025-02-25 20:38       ` Borislav Petkov
2025-02-25 21:03         ` Borislav Petkov
2025-02-25 22:03           ` Rik van Riel
2025-02-26 17:00           ` Tom Lendacky
2025-02-26 17:02             ` Rik van Riel
2025-02-26 17:36               ` Tom Lendacky [this message]
2025-02-26 17:46                 ` Rik van Riel
2025-02-26 18:12                   ` Tom Lendacky
2025-02-26 22:01                     ` Rik van Riel
2025-02-28  1:13                     ` Rik van Riel
2025-02-28 15:02                       ` Tom Lendacky
2025-02-28 15:57                         ` Sean Christopherson
2025-02-28 20:42                         ` Tom Lendacky
2025-02-23 19:48 ` [PATCH v13 07/14] x86/mm: global ASID allocation helper functions Rik van Riel
2025-02-24 14:16   ` Borislav Petkov
2025-02-25 20:22     ` Rik van Riel
2025-02-23 19:48 ` [PATCH v13 08/14] x86/mm: global ASID context switch & TLB flush handling Rik van Riel
2025-02-23 23:08   ` kernel test robot
2025-02-24  1:26     ` Rik van Riel
2025-02-24  2:01     ` Rik van Riel
2025-02-24 18:41   ` kernel test robot
2025-02-23 19:48 ` [PATCH v13 09/14] x86/mm: global ASID process exit helpers Rik van Riel
2025-02-23 19:49 ` [PATCH v13 10/14] x86/mm: enable broadcast TLB invalidation for multi-threaded processes Rik van Riel
2025-02-23 19:49 ` [PATCH v13 11/14] x86/mm: do targeted broadcast flushing from tlbbatch code Rik van Riel
2025-02-23 19:49 ` [PATCH v13 12/14] x86/mm: enable AMD translation cache extensions Rik van Riel
2025-02-23 19:49 ` [PATCH v13 13/14] x86/mm: only invalidate final translations with INVLPGB Rik van Riel
2025-02-23 19:49 ` [PATCH v13 14/14] x86/mm: add noinvlpgb commandline option Rik van Riel
2025-02-23 21:29   ` Borislav Petkov
2025-02-24  0:34     ` Rik van Riel
2025-02-24  6:29       ` Borislav Petkov

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