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 E3BD8C61DBD for ; Tue, 25 Aug 2026 18:55:59 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id DA91F6B0088; Tue, 25 Aug 2026 14:55:58 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id D335E6B008C; Tue, 25 Aug 2026 14:55:58 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id BFAAA6B0095; Tue, 25 Aug 2026 14:55:58 -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 93D486B0088 for ; Tue, 25 Aug 2026 14:55:58 -0400 (EDT) Received: from smtpin29.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay01.hostedemail.com (Postfix) with ESMTP id 0660D1C01BD for ; Tue, 25 Aug 2026 18:55:58 +0000 (UTC) X-FDA: 85140696396.29.D3EA881 Received: from mail-pl1-f197.google.com (mail-pl1-f197.google.com [209.85.214.197]) by imf11.hostedemail.com (Postfix) with ESMTP id 564CC40008 for ; Tue, 25 Aug 2026 18:55:56 +0000 (UTC) Authentication-Results: imf11.hostedemail.com; dkim=pass header.d=google.com header.s=20251104 header.b=CZgOaPXF; spf=pass (imf11.hostedemail.com: domain of 3OuWNagYKCJcJ51EA37FF7C5.3FDC9ELO-DDBM13B.FI7@flex--seanjc.bounces.google.com designates 209.85.214.197 as permitted sender) smtp.mailfrom=3OuWNagYKCJcJ51EA37FF7C5.3FDC9ELO-DDBM13B.FI7@flex--seanjc.bounces.google.com; dmarc=pass (policy=reject) header.from=google.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1787684156; 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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=xccKXo6SW1SbkIzehhqjd8J3GgWcAs1E82/+Xs14ta0=; b=P6yftrbZceUZiM1JOtU0B+h57jxCorR5Dzq3njTkVjVZXDPBCsCUvTb2DuSQs7z936VUTh 5wt1DzII0AQlBRM6iDodwjoUiJ8GFUGFXT3ulGaFMzmKSonYftTr6H2J6dCtP27hXYHMNL zx4fmCtpfPsJI7ux0WdFlwH4LM33oBw= ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1787684156; b=zXxLEVP+uFm+p24GoVPkh4P2yp0uQED0nogj+ZOZUocsUYVyO8dvp+7Cqr5bksyd5rkhgV kTH/BySgsUpEmasx4RyAwodqWCzsGrlUgcgXc3qtI7ZrLiJtTDXdyeU/LUwUbiRbPXbL5c kImeeUiUgSrOQoHhrltWBd1wSfI080g= ARC-Authentication-Results: i=1; imf11.hostedemail.com; dkim=pass header.d=google.com header.s=20251104 header.b=CZgOaPXF; spf=pass (imf11.hostedemail.com: domain of 3OuWNagYKCJcJ51EA37FF7C5.3FDC9ELO-DDBM13B.FI7@flex--seanjc.bounces.google.com designates 209.85.214.197 as permitted sender) smtp.mailfrom=3OuWNagYKCJcJ51EA37FF7C5.3FDC9ELO-DDBM13B.FI7@flex--seanjc.bounces.google.com; dmarc=pass (policy=reject) header.from=google.com Received: by mail-pl1-f197.google.com with SMTP id d9443c01a7336-2cf1c86963bso11966815ad.0 for ; Tue, 25 Aug 2026 11:55:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1787684155; x=1788288955; darn=kvack.org; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:from:to:cc:subject:date:message-id:reply-to :content-type; bh=xccKXo6SW1SbkIzehhqjd8J3GgWcAs1E82/+Xs14ta0=; b=CZgOaPXFDwUyBgkRqclgBryYyl/jhfRPq4bh8m0ADn9s3Li4tI5mSDUoEImJ7vFvdU cveMujEUw51z6wdBq4BlBABn6L7V72gp5q/McBjAR9iWkVQo8o26LtlCIy//2FzUZcbP WFwvUmK+rPfpgLGZAq+qP9ybhkao1ElVV45hsmY0vBSHThbGjqckPyVChtTzM0lSC5PG rVxBTUTYUF8jGzERckOllWyPy01SZWrU1mbDqkdI3Bdi8yJwpDlI2sPsvPxCnowakEFh Q1DOYUfAtNP8rVIvumTgljzxeuRmPQ/NqWOlWARlPK5jhtkPqo1hHxP45Ox83FSB+Ea1 ghhw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1787684155; x=1788288955; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to:content-type; bh=xccKXo6SW1SbkIzehhqjd8J3GgWcAs1E82/+Xs14ta0=; b=hJRNrc+bX4AvEwfzSE2Mkg4I4lQmn6waBj54SkVBduLL1ef0fW3RIg7YaWT/xuUqEp k8XRBxHvuilP6tB3VRuHVujLCulAC2r2TaGjhWqBWCkQ+V8j8FgaSLTB8qbcKeUHGmyL k4OYHttrJVpVqrgWHR9dES8whEBfhiUXRVJxlPQfVgBwFWcLtbPhpmVHW5Vag4I4qr+G WoztZrL23r2brznbrpvKGRRKtK5aiYuYRln+YbLVTxIbcGJCViG9y7MreDhsO1O79GjZ ttz7G3ESJTcDpmyQ+JiSD716R3in2uCFVpY5phjplLfHGt9JAGBBL3ExeudDWgxRvLFG hQug== X-Forwarded-Encrypted: i=1; AHgh+Rr6DgSLkTKv0GAP5LxPv5yXgVArXTPyvdyQvEaACVsWNhBrC+1cmNqxpNLEbgY4ft99nXgmMuqL0A==@kvack.org X-Gm-Message-State: AFuF++n5PUPGVui6RncaySg1AF2smHrOFj2msCZklKo4tYNyJqWBJtpu HmZydPxyptbnu3uFcVo7FHR7WR4E/HY0PnFebO3dD9cPl2qdO0JA1EwJEdHua/A74Oc+wvsWVjS /I0qIYg== X-Received: from pgbdm4.prod.google.com ([2002:a05:6a02:d84:b0:c79:39f0:12f2]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a21:1398:b0:3bf:8de9:c64e with SMTP id adf61e73a8af0-3ceed381cdcmr1617377637.2.1787684154733; Tue, 25 Aug 2026 11:55:54 -0700 (PDT) Date: Tue, 25 Aug 2026 11:55:54 -0700 In-Reply-To: Mime-Version: 1.0 References: <20260807-gmem-inplace-conversion-v10-0-2fc18ee6d3ba@google.com> <20260807-gmem-inplace-conversion-v10-9-2fc18ee6d3ba@google.com> <13ca60c6-e154-4397-8092-09f861e90fe0@kernel.org> <7eba513d-cdae-4832-abac-038dcdd88517@intel.com> Message-ID: Subject: Re: [PATCH v10 09/41] KVM: guest_memfd: Filter both shared and private when invalidating From: Sean Christopherson To: Michael Roth Cc: Xiaoyao Li , Ackerley Tng , Suzuki K Poulose , "David Hildenbrand (Arm)" , 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, 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, aneesh.kumar@kernel.org, liam@infradead.org, Paolo Bonzini , 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 , 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 Content-Type: text/plain; charset="us-ascii" X-Rspam-User: X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 564CC40008 X-Stat-Signature: bgr513tqxx5rutxx87k9f3guwdbrns6q X-HE-Tag: 1787684156-935771 X-HE-Meta: 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 raB1qM1K 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue, Aug 25, 2026, Michael Roth wrote: > On Wed, Aug 26, 2026 at 12:13:47AM +0800, Xiaoyao Li wrote: > > On 8/20/2026 9:32 AM, Sean Christopherson wrote: > > > And vice versa, a PUNCH_HOLE on a SHARED gmem (if userspace is > > > using an INIT_SHARED gmem for the shared branch of a memslot) could invalidate the > > > PRIVATE mappings (of a different gmem instance). > > > > I'm wondering now how this could happen. > > > > the requirement for PUNCH_HOLE on gmem to trigger mapping invalidation is > > the gmem is bound with the memslot. But how can a memslot bound with two > > gmem instances? > > I think this is for when userspace uses an mmap'able guest_memfd instance > to handle shared memory, and a 'normal' guest_memfd instance for private > memory. Each instance is bound to the same memslot/GPA range, and > KVM_SET_MEMORY_ATTRIBUTES handles switching between the 2. Yep, exactly.