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 53038C5AD4E for ; Mon, 10 Aug 2026 08:49:54 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id DAEAA6B008A; Mon, 10 Aug 2026 04:49:52 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id D5FA96B008C; Mon, 10 Aug 2026 04:49:52 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C4F596B0095; Mon, 10 Aug 2026 04:49:52 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id 943FB6B008A for ; Mon, 10 Aug 2026 04:49:52 -0400 (EDT) Received: from smtpin17.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 12FCA1606C8 for ; Mon, 10 Aug 2026 08:49:52 +0000 (UTC) X-FDA: 85084737024.17.BC9A17C Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf23.hostedemail.com (Postfix) with ESMTP id 34D4714000F for ; Mon, 10 Aug 2026 08:49:50 +0000 (UTC) Authentication-Results: imf23.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=LM4dvE+I; spf=pass (imf23.hostedemail.com: domain of david@kernel.org designates 172.234.252.31 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=1786351790; b=RPw9+Gff1mYVAEuH6f12aHroKNtHwoDoAlNyDnOr/H1NAi5zkFATsb1Ys+G2tLKC7CCMDN GUCFnoXRPkVVO4pjqWHy8jCA++PLQFVRLgJ2H6hDF6RmUxOHeWQJ8e7vJ1VVQXJNK4Qbk/ As8pp85J38oh7ZS1iA7vAT6IfMeiHlM= ARC-Authentication-Results: i=1; imf23.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=LM4dvE+I; spf=pass (imf23.hostedemail.com: domain of david@kernel.org designates 172.234.252.31 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=1786351790; 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=oyi1K6Vb11sIVm2DqmDTjgO2DUYGijf3ZjwPoeHhIpI=; b=jb+p15wEYpmPqgPkOKvbRo4+7CALRQ3g1v/2npwHsP+aTemsT6aPcugdau1+uBUqQQJa2N P4OUWLrREEk+UuobAHmguEcZUBpf49lj7TRPulQK41fTYJrAJ1oRi8XMO9S+F/mRg/HseY MgqsAqbIo/znkMiaMa0RMx8Bg+OuILU= Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 3A4C6407C9; Mon, 10 Aug 2026 08:49:49 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 368A41F000E9; Mon, 10 Aug 2026 08:49:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1786351789; bh=oyi1K6Vb11sIVm2DqmDTjgO2DUYGijf3ZjwPoeHhIpI=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=LM4dvE+IKC/Ejo+9/rKz+PKvAdzmvpVvRevxAjCQ5s8v5M45CzxupdrZgWT2JRvuc 5Tizm2ZXxGCYgm9t3tVLtMdV0AoWpSGA7Wm3b5DVASrvII4aYdkcwae8HLnI7Z9i3s iwnnDOx39L6omLCMv2h0Evag/b4MJtfvAfDUxwZ2NHUZclv3+ean7YnI76R2fN0vBZ dWL+WY/+gHBfXv6qPOj4/EeIcc4qXwY/S1hJV1NcE02I67uo7riHg9ePIyU6mqCgxx krur+cesfmybko1Hv3JxueBRP7HRivu3ABRQPWz7RfFxbF5+gWIWyBbqkHUBHDPgHR vl9843J0x9v1g== Message-ID: Date: Mon, 10 Aug 2026 10:49:28 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v10 07/41] KVM: guest_memfd: Stub in ability to enable in-place shared<=>private conversion 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, tabba@google.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, Vlastimil Babka 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, Xiaoyao Li References: <20260807-gmem-inplace-conversion-v10-0-2fc18ee6d3ba@google.com> <20260807-gmem-inplace-conversion-v10-7-2fc18ee6d3ba@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: <20260807-gmem-inplace-conversion-v10-7-2fc18ee6d3ba@google.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 34D4714000F X-Stat-Signature: yga554dauz5uoepa1r6ystidxfem51yt X-Rspam-User: X-Rspamd-Server: rspam04 X-HE-Tag: 1786351790-530257 X-HE-Meta: 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 bRIxBvue uv8UHIlT/MO0TpAN0bc6v/jeJcukH6DdSpIWex9tV6oetzBu+qs5Cgg0H6ag7womIlw67eKOmMZxaAZozHu7byUgzLv852Wa6Psx/E801Ie8eIvBct5Wgboljo8jnIbRmscHpw/kB5tUCWJj61b6L27DUP+6fJmJeLtbhgzLyr+hglyj84H7Ve1O/bsu/2O+rAEZDGE+xJKiLknLf/F9eSwF5TNMSE9A7P2JICqAVMjMENVdT/GynIiKn7vlGxEJiM0BVvRn6JNfF9FPHjBgsEpT6FQjVahqCmSyNXb4IRSsqHr2jS07v3MC/UhoC22SjUImP5JWqcbPZxfoj1FCZDmBPmtv+wy1v3vKd Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 8/7/26 23:52, Ackerley Tng via B4 Relay wrote: > From: Sean Christopherson > > Stub in global variable to enable in-place guest_memfd private<=>shared > memory conversion, which will eventually be exposed to userspace via a > module param, and wire up the __kvm_mem_is_private() static call to the > guest_memfd version when in-place conversion is enabled, i.e. when gmem is > the sole authority on private vs. shared memory. > > Cc: Fuad Tabba > Cc: Xiaoyao Li > Signed-off-by: Sean Christopherson > Co-developed-by: Ackerley Tng > Signed-off-by: Ackerley Tng > --- > include/linux/kvm_host.h | 6 ++++++ > virt/kvm/guest_memfd.c | 26 ++++++++++++++++++++++++++ > virt/kvm/kvm_main.c | 12 +++++++++++- > 3 files changed, 43 insertions(+), 1 deletion(-) > > diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h > index 65fbce46b63f4..9477ecebbbced 100644 > --- a/include/linux/kvm_host.h > +++ b/include/linux/kvm_host.h > @@ -2580,6 +2580,8 @@ static inline bool kvm_vm_mem_is_private(struct kvm *kvm, gfn_t gfn) > #endif /* CONFIG_KVM_VM_MEMORY_ATTRIBUTES */ > > #ifdef kvm_arch_has_private_mem > +extern bool gmem_in_place_conversion; Is there a "supports/has/enable" in there? And should we call it "kvm_gmem" for completeness? > + > typedef bool (kvm_mem_is_private_t)(struct kvm *kvm, gfn_t gfn); > DECLARE_STATIC_CALL(__kvm_mem_is_private, kvm_mem_is_private_t); > > @@ -2588,6 +2590,8 @@ static inline bool kvm_mem_is_private(struct kvm *kvm, gfn_t gfn) > return static_call(__kvm_mem_is_private)(kvm, gfn); > } > #else > +#define gmem_in_place_conversion false > + > static inline bool kvm_mem_is_private(struct kvm *kvm, gfn_t gfn) > { > return false; > @@ -2595,6 +2599,8 @@ static inline bool kvm_mem_is_private(struct kvm *kvm, gfn_t gfn) > #endif /* kvm_arch_has_private_mem */ > > #ifdef CONFIG_KVM_GUEST_MEMFD > +bool kvm_gmem_is_private(struct kvm *kvm, gfn_t gfn); As mentioned in v9, the name is confusing. kvm_gmem_mem_is_private ? -- Cheers, David