From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E73D72FBDF4; Wed, 26 Nov 2025 10:25:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764152733; cv=none; b=LqEBM0dlf8ocbMbh3yCD71f91x0zeqhRMtp9xGfXwGlanbbsC71vVHLSzhuomg4eixPOK6+lQiFwpVca+o2GbExSn7wcddINKEOWkSO8nyLNIj+rYxOdZqvkCS1qakRc0CcRvXi2Av4LFPXoHacMcFWGfKL7A04eHjoj0WgSEc0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764152733; c=relaxed/simple; bh=ADT5O93kPzD5IUnxNtMCPvZ3ykq6P2gnQ8CL/G2R2Yg=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=OV6iP5+SWanTRhlmJAR9oaUO1gNxFcJdFXNfyZRX7NNnTqH8ibpOkstxuYshouIJX2DFigKXZqjlqEWm5vQAIHWzZB4p9xQENlAkDO1r/5Yt/iOpfCi75EbtNFPoDkF6wQysDcdKnGMTpAm7RA015tw5e8TK65aRK/TwhfMNnGs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=TiYIuCSU; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="TiYIuCSU" 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 Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: 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 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