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 6ADEFD1039D for ; Wed, 26 Nov 2025 10:25:36 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id C6AC06B0030; Wed, 26 Nov 2025 05:25:35 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id C40B56B0032; Wed, 26 Nov 2025 05:25:35 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B7DF86B0062; Wed, 26 Nov 2025 05:25:35 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id A7A326B0030 for ; Wed, 26 Nov 2025 05:25:35 -0500 (EST) Received: from smtpin09.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id 50B471313B7 for ; Wed, 26 Nov 2025 10:25:35 +0000 (UTC) X-FDA: 84152376630.09.A49FB30 Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by imf20.hostedemail.com (Postfix) with ESMTP id A84271C000C for ; Wed, 26 Nov 2025 10:25:33 +0000 (UTC) Authentication-Results: imf20.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=TiYIuCSU; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf20.hostedemail.com: domain of david@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=david@kernel.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1764152733; a=rsa-sha256; cv=none; b=jBqvhG0LhTaB0eSsFkI1HliD3Ad/27UYuFoBJ2QH602OlGjrHv/gR0sdX2XYLBAopFiO7i MtYw6lCgjnly2FpEFPX0EknKqzzBvD0GVmFLpSyX/LcMbKYOgTFkDGbJYqrhX4VhXE8wUA +o8KJgEBto7t+0RgdIaD34XGnA6CkEk= ARC-Authentication-Results: i=1; imf20.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=TiYIuCSU; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf20.hostedemail.com: domain of david@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=david@kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1764152733; 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=hW/OEtBaLBibMkDeiCdPpW9Ckmbp4r8bTfP1ufFelyc=; b=gp4s7NIuLe/XhKqxRd25cK5dPQDdW5pWCsyW8W754KCo3zP+y6gRQF9YJYisVk63f72vZP /qr4EPkHdZMy4RSJTVIkFvk6CxPhfI9YzYl2EYiYqB0DgPgHGKbpAbbcA6M4p2kyeTeWck i7+j02yN1ZKjuF5RxIrbfop+dAzhWmw= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id 1A84D601D2; Wed, 26 Nov 2025 10:25:33 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D812DC113D0; Wed, 26 Nov 2025 10:25:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1764152732; bh=ADT5O93kPzD5IUnxNtMCPvZ3ykq6P2gnQ8CL/G2R2Yg=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=TiYIuCSUq9QRRGD2topIHFwl1vopc3ZLruOXHs9PFa6hrCZl0gnj1E9KSrDUQJm07 Tv2dPgpe3TaU6zrGMJiYz/x1RjJiYCjoS0tWUnyMxE0aStEXScEdG2/MVbTeNhoIVw EomHvzqTzMRIzPfLH7bujkmAqtrGEN0VnxmAs5RvxuGwlrrp+DmrBbQvImxbMcbW8D SVGGQixWkF/Gh/TJQBL9VRoZsTyCFez7z9R8SR5ePpkEB7PWuFqg6ceVrItOwBEDvf pXXPBuDQ4gTuQ1h+pmAsLjdmmzhrY/aPHEh4kchNz2BfsZf8keHL7/sCIG2gn2B0Wh KCmcjSEepjGFA== Message-ID: <3d5096cd-39b5-4280-95a1-78998a4e609e@kernel.org> Date: Wed, 26 Nov 2025 11:25:25 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 4/5] guest_memfd: add support for userfaultfd minor mode To: Mike Rapoport , linux-mm@kvack.org Cc: Andrea Arcangeli , Andrew Morton , Axel Rasmussen , Baolin Wang , Hugh Dickins , James Houghton , "Liam R. Howlett" , Lorenzo Stoakes , Michal Hocko , Nikita Kalyazin , Paolo Bonzini , Peter Xu , Sean Christopherson , Shuah Khan , Suren Baghdasaryan , Vlastimil Babka , linux-kernel@vger.kernel.org, kvm@vger.kernel.org, linux-kselftest@vger.kernel.org References: <20251125183840.2368510-1-rppt@kernel.org> <20251125183840.2368510-5-rppt@kernel.org> From: "David Hildenbrand (Red Hat)" Content-Language: en-US In-Reply-To: <20251125183840.2368510-5-rppt@kernel.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: A84271C000C X-Stat-Signature: 5kb8gbkcjasj4zrym3zfo8msw8ts1bog X-Rspam-User: X-HE-Tag: 1764152733-8771 X-HE-Meta: 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 gpCLYf2c N14h9x+hVd355IwGJP44NOlnxKsV3FZ7ToMsjkUUZUr3eIQ3bjG0wEIuuEgxF5M2bkve1U6TdtgZAwBdkN8yciHMwRMcucYZXSL5prtvCw2zciXvck544fYRqDwBX2Clw+TovLdato2l8T9BEC70u77k5BG/g4anNjFWRABAkvekdjr438sZemHInDNh0v6QrbktPE9GUjVKET8JeSAjK8GzCQb3MR1WZJL7LRdpOlbd9zj64/ytFzbK+ol3vSUGnaAjXmm3cX/tLNzrNUS874QAk8xcvsHWD32ZAYQElqPczFVSf3m0oqX591eFOaHWLo5dZYdhGRvBE/sg= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 11/25/25 19:38, Mike Rapoport wrote: > From: "Mike Rapoport (Microsoft)" > > userfaultfd notifications about minor page faults used for live migration > and snapshotting of VMs with memory backed by shared hugetlbfs or tmpfs > mappings as described in detail in commit 7677f7fd8be7 ("userfaultfd: add > minor fault registration mode"). > > To use the same mechanism for VMs that use guest_memfd to map their memory, > guest_memfd should support userfaultfd minor mode. > > Extend ->fault() method of guest_memfd with ability to notify core page > fault handler that a page fault requires handle_userfault(VM_UFFD_MINOR) to > complete and add implementation of ->get_shared_folio() to guest_memfd > vm_ops. > > Signed-off-by: Mike Rapoport (Microsoft) > --- No exports and still looks clean to me, nice. :) -- Cheers David