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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7F8BDC0015E for ; Fri, 21 Jul 2023 17:50:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229820AbjGURuO (ORCPT ); Fri, 21 Jul 2023 13:50:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49486 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229782AbjGURuN (ORCPT ); Fri, 21 Jul 2023 13:50:13 -0400 Received: from mail-yb1-xb4a.google.com (mail-yb1-xb4a.google.com [IPv6:2607:f8b0:4864:20::b4a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 95A2935A7 for ; Fri, 21 Jul 2023 10:50:08 -0700 (PDT) Received: by mail-yb1-xb4a.google.com with SMTP id 3f1490d57ef6-c8f360a07a2so2029813276.2 for ; Fri, 21 Jul 2023 10:50:08 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1689961807; x=1690566607; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=cGq520d0DqyrCnCF7s5Hdb0rD6NYwtkYzvVScy9HYVY=; b=lZQ3ytVABaMbgeRDyRyj2Y4aroG9rwZE4tos1KIi9+yVur8kHjUJfNDjBsWbA5klWv TLcM88saeccS8fNt+F3rMDPeeLUphdScBaSRyrIwijc1R9havyOwlUNE/IQcuJNK+B8L fg4nRh9mVWUewpR8WoS4y2UShReGqGQI/p2sPXI0/xi9S/4bLyRSoR+wjHm8ngFldPX/ svRbdc4YBfOK5kZ24vC9n3F8L7Li2/2X6A5zsHfs5DeCFBQGgpDd6R/Lv+3ONLhdKh+D zucg4UeBA4sEAN2XLHlR2RolIKqE8NS9aws4SoQANyJbQckavpkDoby1VzLjItanYN4z z0Aw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1689961808; x=1690566608; h=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; bh=cGq520d0DqyrCnCF7s5Hdb0rD6NYwtkYzvVScy9HYVY=; b=TGQw4MD0ZjUoPnbHIIEbaOK7kJWVgtEkjSdZmmvsPUqhEnfNDC+rL0pqZgA/7OwJJA 2zQMjjmJaC7hIyGT/1XEubicTBRkm+uYpD2vqd5zvB1Y4bJS+VihIDu/fqVagdZAaqtt AuSZ577HqzG+0ALxtiCfyj+gnro7DXWlLb7/+tN7NtLRPwGEj7MuENxXraf/4tfORsgj TlTBHFMQHZw48jvUsF7TmUwSPrJ6LoKKByb4DKIFPP1YRGP41w9g+GUJselFSvQ5u3Q1 Dt8oJbd126Bz0yPvanJjFjHztxvE8rXlK3DbSA2YA22UK9iKZ9VN3e0GdS9jWUHUAgzd cdew== X-Gm-Message-State: ABy/qLbe8m+XdZo1lFBolNGSEjbqFhFfSamEzlFf5JcYNfQ3BxKZD7Bc LoXibLuo7bgyXz5nlcpJsREXlJMrUHg= X-Google-Smtp-Source: APBJJlGQVjm5RzrpH36bdluvnqR1OmovIF/Mv2HtKZQ0PUD+Zj6xyTxIa85gQ91Vm5Bag6YHDA7hXUEb4so= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a05:6902:10cd:b0:c1c:df23:44ee with SMTP id w13-20020a05690210cd00b00c1cdf2344eemr19769ybu.0.1689961807734; Fri, 21 Jul 2023 10:50:07 -0700 (PDT) Date: Fri, 21 Jul 2023 10:50:06 -0700 In-Reply-To: <8ad7a846-64e9-a3f1-4bf1-731a994d62cb@redhat.com> Mime-Version: 1.0 References: <20230718234512.1690985-1-seanjc@google.com> <20230718234512.1690985-13-seanjc@google.com> <8ad7a846-64e9-a3f1-4bf1-731a994d62cb@redhat.com> Message-ID: Subject: Re: [RFC PATCH v11 12/29] KVM: Add KVM_CREATE_GUEST_MEMFD ioctl() for guest-specific backing memory From: Sean Christopherson To: Paolo Bonzini Cc: Marc Zyngier , Oliver Upton , Huacai Chen , Michael Ellerman , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , "Matthew Wilcox (Oracle)" , Andrew Morton , Paul Moore , James Morris , "Serge E. Hallyn" , kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, Chao Peng , Fuad Tabba , Jarkko Sakkinen , Yu Zhang , Vishal Annapurve , Ackerley Tng , Maciej Szmigiero , Vlastimil Babka , David Hildenbrand , Quentin Perret , Michael Roth , Wang , Liam Merwick , Isaku Yamahata , "Kirill A . Shutemov" Content-Type: text/plain; charset="us-ascii" Precedence: bulk List-ID: On Fri, Jul 21, 2023, Paolo Bonzini wrote: > On 7/19/23 01:44, Sean Christopherson wrote: > > + inode = alloc_anon_inode(mnt->mnt_sb); > > + if (IS_ERR(inode)) > > + return PTR_ERR(inode); > > + > > + err = security_inode_init_security_anon(inode, &qname, NULL); > > + if (err) > > + goto err_inode; > > + > > I don't understand the need to have a separate filesystem. If it is to > fully setup the inode before it's given a struct file, why not just export > anon_inode_make_secure_inode instead of security_inode_init_security_anon? Ugh, this is why comments are important, I can't remember either. I suspect I implemented a dedicated filesystem to kinda sorta show that we could allow userspace to provide the mount point with e.g. NUMA hints[*]. But my preference would be to not support a userspace provided mount and instead implement fbind() to let userspace control NUMA and whatnot. [*] https://lore.kernel.org/all/ef48935e5e6f947f6f0c6d748232b14ef5d5ad70.1681176340.git.ackerleytng@google.com