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Peter Anvin" , stable@vger.kernel.org, Sander Eikelenboom , xen-devel@lists.xenproject.org, x86@kernel.org, linux-kernel@vger.kernel.org References: <20210908073640.11299-1-jgross@suse.com> From: Jan Beulich Message-ID: <5a4859db-d173-88dd-5ea9-dd5fd893d934@suse.com> Date: Wed, 8 Sep 2021 13:07:59 +0200 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.13.0 In-Reply-To: <20210908073640.11299-1-jgross@suse.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-ClientProxiedBy: PR3P193CA0052.EURP193.PROD.OUTLOOK.COM (2603:10a6:102:51::27) To VI1PR04MB5600.eurprd04.prod.outlook.com (2603:10a6:803:e7::16) MIME-Version: 1.0 X-MS-Exchange-MessageSentRepresentingType: 1 Received: from [10.156.60.236] (37.24.206.209) by PR3P193CA0052.EURP193.PROD.OUTLOOK.COM (2603:10a6:102:51::27) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.4478.22 via Frontend Transport; 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The description of that change starts with "pmd/pud_populate is the right interface to be used to set the respective page table entries." If this is deemed true, I don't think pmd_populate() should call paravirt_alloc_pte(): The latter function, as its name says, is supposed to be called for newly allocated page tables only (aiui). > Today pmd/pud_poplulate() for Xen PV assumes that the PFN inserted is > referencing a not yet used page table. In case of move_normal_pmd/pud() > this is not true, resulting in WARN splats like: I agree for the PMD part, but is including PUD here really correct? While I don't know why that is, xen_alloc_ptpage() pins L1 tables only. Hence a PUD update shouldn't be able to find a pinned L2 table. Jan