From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id DAABECEBF8C for ; Fri, 27 Sep 2024 09:46:18 +0000 (UTC) Received: from list by lists.xenproject.org with outflank-mailman.806185.1217532 (Exim 4.92) (envelope-from ) id 1su7Y9-00061P-Ap; Fri, 27 Sep 2024 09:46:09 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 806185.1217532; Fri, 27 Sep 2024 09:46:09 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1su7Y9-00061I-7D; Fri, 27 Sep 2024 09:46:09 +0000 Received: by outflank-mailman (input) for mailman id 806185; Fri, 27 Sep 2024 09:46:08 +0000 Received: from se1-gles-flk1-in.inumbo.com ([94.247.172.50] helo=se1-gles-flk1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1su7Y8-00061C-Ot for xen-devel@lists.xenproject.org; Fri, 27 Sep 2024 09:46:08 +0000 Received: from mail-ej1-x635.google.com (mail-ej1-x635.google.com [2a00:1450:4864:20::635]) by se1-gles-flk1.inumbo.com (Halon) with ESMTPS id 4f4b862e-7cb5-11ef-99a2-01e77a169b0f; Fri, 27 Sep 2024 11:46:03 +0200 (CEST) Received: by mail-ej1-x635.google.com with SMTP id a640c23a62f3a-a8a6d1766a7so249593466b.3 for ; Fri, 27 Sep 2024 02:46:03 -0700 (PDT) Received: from localhost ([213.195.124.163]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-a93c2777214sm110811866b.36.2024.09.27.02.46.02 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 27 Sep 2024 02:46:02 -0700 (PDT) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: 4f4b862e-7cb5-11ef-99a2-01e77a169b0f DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=citrix.com; s=google; t=1727430363; x=1728035163; darn=lists.xenproject.org; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:from:date:from:to :cc:subject:date:message-id:reply-to; bh=wKkmpdxyCD/kGB5RbbxBO1xx2S5PshYKqNzT9T91YPk=; b=Ol+tOEU7C3kDkdFzAn+ufLj6Qfnh190rD9Lq4f6isX7PDcNw+MAMVBqtu5rjCoxrQk ziVr3uIUbOpXOc2Twx2n9Bjh7yCoDqYmHFIh8K+VWGXY6ALPSyZLhuipS4MYlwPpVQie L6S93sGaJoveXOdp5GKQx8UWwe9cWHjITmTT8= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1727430363; x=1728035163; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:from:date :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=wKkmpdxyCD/kGB5RbbxBO1xx2S5PshYKqNzT9T91YPk=; b=ug8dfh0lGMy8ZVh7aYak1SXjM1S+HPzGvryIchQIJWVkpBDlMVjwQTc67VD74BVoim W0C9kkZ4VgFOVzZORzHxvNwUfvnrgt71kRqvXBFfWzYzhMXk1dOw5ZAzqS9t6fW3TBNV 1cRNzKknF7vKMRLFN0jZ6bNM5fNYUeXPYilpbST3yjhDBkPmIawdbv4cxfHm4JcUfUnk NVFGEhnUVuyCCYCWK6ERI81LQi5jpjsMxJOhNSQImT3DHd9TIExJ/76O2I9caGsCFvIS HhGv5V7ZjYKV467wrxjg7/+1yhAKQS1F3frxB8HqLuA5sLA/Yu2vc2La5khaNfhhK7vR ro0w== X-Gm-Message-State: AOJu0Ywy8fsDK3U2K+YpvLryY0I98qFYjID8GUQWdjOwm6KWSfjtATJu Wtm/iv4czE26nhFsCuO6hjzbVzWEDSFbIr14k0idSPdFGmJIdiUD/mWTJxjkUwVAUOfyTBfeGcu j X-Google-Smtp-Source: AGHT+IHuR3Eo29tOM+vFsMSIEsCj9qFo2sDkI71rHQzduLwDSawjapOKG32ctbedKhuSoRA1ZU1o2Q== X-Received: by 2002:a17:906:7946:b0:a8a:7897:c043 with SMTP id a640c23a62f3a-a93c4ae12c7mr241455266b.43.1727430362865; Fri, 27 Sep 2024 02:46:02 -0700 (PDT) Date: Fri, 27 Sep 2024 11:46:01 +0200 From: Roger Pau =?utf-8?B?TW9ubsOp?= To: Alejandro Vallejo Cc: xen-devel@lists.xenproject.org, Jan Beulich , Andrew Cooper Subject: Re: [PATCH 16/22] x86/mm: introduce a per-CPU L3 table for the per-domain slot Message-ID: References: <20240726152206.28411-1-roger.pau@citrix.com> <20240726152206.28411-17-roger.pau@citrix.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: On Fri, Aug 16, 2024 at 07:40:40PM +0100, Alejandro Vallejo wrote: > On Fri Jul 26, 2024 at 4:22 PM BST, Roger Pau Monne wrote: > > So far L4 slot 260 has always been per-domain, in other words: all vCPUs of a > > domain share the same L3 entry. Currently only 3 slots are used in that L3 > > table, which leaves plenty of room. > > > > Introduce a per-CPU L3 that's used the the domain has Address Space Isolation > > enabled. Such per-CPU L3 gets currently populated using the same L3 entries > > present on the per-domain L3 (d->arch.perdomain_l3_pg). > > > > No functional change expected, as the per-CPU L3 is always a copy of the > > contents of d->arch.perdomain_l3_pg. > > > > Note that all the per-domain L3 entries are populated at domain create, and > > hence there's no need to sync the state of the per-CPU L3 as the domain won't > > yet be running when the L3 is modified. > > > > Signed-off-by: Roger Pau Monné > > Still scratching my head with the details on this, but in general I'm utterly > confused whenever I read per-CPU in the series because it's not obvious which > CPU (p or v) I should be thinking about. A general change that would help a lot > is to replace every instance of per-CPU with per-vCPU or per-pCPU as needed. per-CPU is always per-pCPU, as CPU without any prefix should always refer to a physical CPU. I think it's only recently that we have started using pCPU vs vCPU, in the past it always was CPU vs vCPU. I will attempt to be better at explicitly using pCPU instead of CPU in the commit messages, sorry. Thanks, Roger.