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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 8D2A5C79FBD for ; Wed, 9 Sep 2026 16:04:24 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 85B0A6B009E; Wed, 9 Sep 2026 12:04:23 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 81BB26B00AA; Wed, 9 Sep 2026 12:04:23 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 732AC6B00AB; Wed, 9 Sep 2026 12:04:23 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 3E7C56B009E for ; Wed, 9 Sep 2026 12:04:23 -0400 (EDT) Received: from smtpin27.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay06.hostedemail.com (Postfix) with ESMTP id CC9ACA43D9 for ; Wed, 9 Sep 2026 16:04:22 +0000 (UTC) X-FDA: 85194695964.27.C08D355 Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by imf23.hostedemail.com (Postfix) with ESMTP id F10B814000A for ; Wed, 9 Sep 2026 16:04:20 +0000 (UTC) Authentication-Results: imf23.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=N5Byjyq7; spf=pass (imf23.hostedemail.com: domain of david@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=david@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1788969861; b=xuIQTsPswSTMduwZez2xWqvb6OG4Gbn4bxBZL51eat3eqKyUFOJRbXFAMhFCSknKVpCRHF ffR2G9JBLND+kop0dMlXGgUs7cARfCS5QY7rmIKcxUvtmhfxcOO7kQ9mtkCPJj9EqVjA6l 7M3fSOJsG2wSeXl+Xx2fsenU+DeSRWY= ARC-Authentication-Results: i=1; imf23.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=N5Byjyq7; spf=pass (imf23.hostedemail.com: domain of david@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=david@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1788969861; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=Dk4sipXK68/lmwCc15T8zbjLDSh1adJ4SNP0vi3NXZ4=; b=mjvE1WhTUd7SahgZLz1PwIzSWuZCB4+30ItKKi9SsxavFFy2l21MoM0MCM55+BaRmy9nFh QE4NvU5umojYrxJzfEF++2Y/4mLn116pI051jcnJ8UxzAlUOWMjXqRJR8d0UAJ+rnbkIso SXr7BJXMsxoGq/qszoaOZs7W/moQYXE= Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id 38F8A601F0; Wed, 9 Sep 2026 16:04:20 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3BA101F00A3D; Wed, 9 Sep 2026 16:03:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788969859; bh=Dk4sipXK68/lmwCc15T8zbjLDSh1adJ4SNP0vi3NXZ4=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=N5Byjyq7obOB27n73VYuETuGMgxQqZ+4uhJtACmOFqhcEPaUoNKD2aXjdV+ITaH+G UnPbxBOmzkYV55oRKDkAQbky+J+Vpfri7xM6m3QbpgNkWbe5uTJcxn15Nv/D6cNIvS tl/lEN++DrWlUG8ihLFwAdERRhpxECLPBAjwSuL/8bmKXMJ6MgTEJlK6EvNYlYI88T T48dYf95LW8RuQrgH/FByYkSqQVNdGlgkKg5PKSuoYijMxSTnFrRK5RB6zrjjEGw1Z YGU5DL38OYmPx6qPPWdZzz84LGm+oNBNJtnNRAKKkTzfx+1XAdUdVWFeVpgtUxIicK JK65Sc+BlJsQw== Message-ID: <307df445-8b53-4de9-8e69-3c586a44be9f@kernel.org> Date: Wed, 9 Sep 2026 18:03:56 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v12 11/45] KVM: guest_memfd: Invalidate both SHARED and PRIVATE mappings for in-place conversions To: ackerleytng@google.com, aik@amd.com, andrew.jones@linux.dev, binbin.wu@linux.intel.com, brauner@kernel.org, chao.p.peng@linux.intel.com, jmattson@google.com, jthoughton@google.com, michael.roth@amd.com, oupton@kernel.org, pankaj.gupta@amd.com, qperret@google.com, rick.p.edgecombe@intel.com, rientjes@google.com, shivankg@amd.com, steven.price@arm.com, willy@infradead.org, wyihan@google.com, yan.y.zhao@intel.com, forkloop@google.com, pratyush@kernel.org, suzuki.poulose@arm.com, aneesh.kumar@kernel.org, liam@infradead.org, Paolo Bonzini , Sean Christopherson , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Steven Rostedt , Masami Hiramatsu , Mathieu Desnoyers , Jonathan Corbet , Shuah Khan , Shuah Khan , Vishal Annapurve , Andrew Morton , Chris Li , Kairui Song , Kemeng Shi , Nhat Pham , Barry Song , Axel Rasmussen , Yuanchu Xie , Wei Xu , Youngjun Park , Qi Zheng , Shakeel Butt , Kiryl Shutsemau , Baoquan He , Jason Gunthorpe , John Hubbard , Peter Xu , tarunsahu@google.com, Randy Dunlap , Lorenzo Stoakes , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Fuad Tabba Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-mm@kvack.org, linux-coco@lists.linux.dev References: <20260830-gmem-inplace-conversion-v12-0-85e5fd25252a@google.com> <20260830-gmem-inplace-conversion-v12-11-85e5fd25252a@google.com> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; keydata= xsFNBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzS5EYXZpZCBIaWxk ZW5icmFuZCAoQ3VycmVudCkgPGRhdmlkQGtlcm5lbC5vcmc+wsGQBBMBCAA6AhsDBQkmWAik AgsJBBUKCQgCFgICHgUCF4AWIQQb2cqtc1xMOkYN/MpN3hD3AP+DWgUCaYJt/AIZAQAKCRBN 3hD3AP+DWriiD/9BLGEKG+N8L2AXhikJg6YmXom9ytRwPqDgpHpVg2xdhopoWdMRXjzOrIKD g4LSnFaKneQD0hZhoArEeamG5tyo32xoRsPwkbpIzL0OKSZ8G6mVbFGpjmyDLQCAxteXCLXz ZI0VbsuJKelYnKcXWOIndOrNRvE5eoOfTt2XfBnAapxMYY2IsV+qaUXlO63GgfIOg8RBaj7x 3NxkI3rV0SHhI4GU9K6jCvGghxeS1QX6L/XI9mfAYaIwGy5B68kF26piAVYv/QZDEVIpo3t7 /fjSpxKT8plJH6rhhR0epy8dWRHk3qT5tk2P85twasdloWtkMZ7FsCJRKWscm1BLpsDn6EQ4 jeMHECiY9kGKKi8dQpv3FRyo2QApZ49NNDbwcR0ZndK0XFo15iH708H5Qja/8TuXCwnPWAcJ DQoNIDFyaxe26Rx3ZwUkRALa3iPcVjE0//TrQ4KnFf+lMBSrS33xDDBfevW9+Dk6IISmDH1R HFq2jpkN+FX/PE8eVhV68B2DsAPZ5rUwyCKUXPTJ/irrCCmAAb5Jpv11S7hUSpqtM/6oVESC 3z/7CzrVtRODzLtNgV4r5EI+wAv/3PgJLlMwgJM90Fb3CB2IgbxhjvmB1WNdvXACVydx55V7 LPPKodSTF29rlnQAf9HLgCphuuSrrPn5VQDaYZl4N/7zc2wcWM7BTQRVy5+RARAA59fefSDR 9nMGCb9LbMX+TFAoIQo/wgP5XPyzLYakO+94GrgfZjfhdaxPXMsl2+o8jhp/hlIzG56taNdt VZtPp3ih1AgbR8rHgXw1xwOpuAd5lE1qNd54ndHuADO9a9A0vPimIes78Hi1/yy+ZEEvRkHk /kDa6F3AtTc1m4rbbOk2fiKzzsE9YXweFjQvl9p+AMw6qd/iC4lUk9g0+FQXNdRs+o4o6Qvy iOQJfGQ4UcBuOy1IrkJrd8qq5jet1fcM2j4QvsW8CLDWZS1L7kZ5gT5EycMKxUWb8LuRjxzZ 3QY1aQH2kkzn6acigU3HLtgFyV1gBNV44ehjgvJpRY2cC8VhanTx0dZ9mj1YKIky5N+C0f21 zvntBqcxV0+3p8MrxRRcgEtDZNav+xAoT3G0W4SahAaUTWXpsZoOecwtxi74CyneQNPTDjNg azHmvpdBVEfj7k3p4dmJp5i0U66Onmf6mMFpArvBRSMOKU9DlAzMi4IvhiNWjKVaIE2Se9BY FdKVAJaZq85P2y20ZBd08ILnKcj7XKZkLU5FkoA0udEBvQ0f9QLNyyy3DZMCQWcwRuj1m73D sq8DEFBdZ5eEkj1dCyx+t/ga6x2rHyc8Sl86oK1tvAkwBNsfKou3v+jP/l14a7DGBvrmlYjO 59o3t6inu6H7pt7OL6u6BQj7DoMAEQEAAcLBfAQYAQgAJgIbDBYhBBvZyq1zXEw6Rg38yk3e EPcA/4NaBQJonNqrBQkmWAihAAoJEE3eEPcA/4NaKtMQALAJ8PzprBEXbXcEXwDKQu+P/vts IfUb1UNMfMV76BicGa5NCZnJNQASDP/+bFg6O3gx5NbhHHPeaWz/VxlOmYHokHodOvtL0WCC 8A5PEP8tOk6029Z+J+xUcMrJClNVFpzVvOpb1lCbhjwAV465Hy+NUSbbUiRxdzNQtLtgZzOV Zw7jxUCs4UUZLQTCuBpFgb15bBxYZ/BL9MbzxPxvfUQIPbnzQMcqtpUs21CMK2PdfCh5c4gS sDci6D5/ZIBw94UQWmGpM/O1ilGXde2ZzzGYl64glmccD8e87OnEgKnH3FbnJnT4iJchtSvx yJNi1+t0+qDti4m88+/9IuPqCKb6Stl+s2dnLtJNrjXBGJtsQG/sRpqsJz5x1/2nPJSRMsx9 5YfqbdrJSOFXDzZ8/r82HgQEtUvlSXNaXCa95ez0UkOG7+bDm2b3s0XahBQeLVCH0mw3RAQg r7xDAYKIrAwfHHmMTnBQDPJwVqxJjVNr7yBic4yfzVWGCGNE4DnOW0vcIeoyhy9vnIa3w1uZ 3iyY2Nsd7JxfKu1PRhCGwXzRw5TlfEsoRI7V9A8isUCoqE2Dzh3FvYHVeX4Us+bRL/oqareJ CIFqgYMyvHj7Q06kTKmauOe4Nf0l0qEkIuIzfoLJ3qr5UyXc2hLtWyT9Ir+lYlX9efqh7mOY qIws/H2t In-Reply-To: <20260830-gmem-inplace-conversion-v12-11-85e5fd25252a@google.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspam-User: X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: F10B814000A X-Stat-Signature: c6cecinxwd6m3sm3es51s17x6ditqebb X-HE-Tag: 1788969860-317729 X-HE-Meta: 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 1g6tlkYf B8neu8mixIbTWi/ADTtOGWnesFNmD8qaDt3Ma2nRRBfrYRllI8kSpIaOdls4H/0prVmtQYJKUz/MsUZXbW654cBjD7PTqt1RmYGgzqWfb8KI6RPMGNAe0tyZvD/iX16s5OW/9o5DgD8+vvAE/JrLfUBsyXw5vE9/1pejGh7/LfkZhffiZsgL+fpazUzfnNEQ6JrRyBKKrsTSAEUvLtVv0xfGEWAByO65y4iG5XdE6tTtWffr9ZT3soRWRt4kZMi/NJX1bqacXOZr/WorGnmlHetxOIkV0FjBKK0cCHj5BE7nlKvVUGafJhS6nil6NNiFzhqcOo9ka8EWaOONkI9Lgy7LQEgolkUCn2xXC Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 8/31/26 02:25, Ackerley Tng via B4 Relay wrote: > From: Sean Christopherson > > When removing one or more folios from a guest_memfd instance, invalidate > both SHARED and PRIVATE mappings if in-place conversion is enabled, because > stating the obvious, KVM needs to ensure that all mappings to the folio(s) > are dropped. > > Opportunistically rename the helper to capture that it returns a filter for > all gfns in anticipation of zapping only the previous mapping types on > conversion. I.e. when doing in-place conversion to PRIVATE, only SHARED > mappings need to be zapped (ignoring that KVM would ideally not invalidate > ranges whose attributes aren't changing in the first place). > > Note, precisely zapping only the possible mapping types when in-place > conversion is disabled is important for functional correctness, not just > for performance. Specifically, if KVM zaps both when SHARED vs. PRIVATE is > tracked per-VM, then a PUNCH_HOLE operation on a PRIVATE guest_memfd will > incorrectly zap SHARED mappings that have nothing to do with that gmem > instance (because they're mapped via a VMA, not a gmem fd). > > The incorrect over-zapping of SHARED memory that doesn't belong to the gmem > fd requesting the zapping will be resolved in a later patch, where, if > in-place conversion is enabled, KVM will use both shared and private memory > from the guest_memfd. If both shared and private memory are from the > guest_memfd, invalidation will only zap memory belonging to the given gmem > instance. > > Signed-off-by: Sean Christopherson > Signed-off-by: Ackerley Tng > --- Reviewed-by: David Hildenbrand (Arm) -- Cheers, David