From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-yb1-f201.google.com (mail-yb1-f201.google.com [209.85.219.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id F13CC27F00 for ; Fri, 21 Jul 2023 17:50:08 +0000 (UTC) Received: by mail-yb1-f201.google.com with SMTP id 3f1490d57ef6-bc68c4e046aso2045232276.0 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=1689961807; x=1690566607; 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=iBxvA7WSx/xUXW0i6IUQZYzOOy2x3X8oAVe6RZrF7X+8mlxNnj1D9UwuZepTZ5ZpDV Z2P8OC9raM+Asj6H7ZrjZczrir5QKnixg8wFgtCmqoAmyC1nJOO/YDtk+2i/OZauFpzF 7/hXiUR2l1TyUGLUWnO6Iw0JQUb6dmSnLCziZ4Aoe7QE8KWDcEXo+Gt9IVIGbis9AaQG asSCj+xxPF5FBWOmDByPqgAGJsIb5G9QsTD8UyI/K6oHn7wRIGPlcAh+QcAs2f3Fq58q i6aYmnmJ0XFu9miUCUUNO0fiXcrqR1iEO43HGA2CNItc9Opd/I5x+kCCT6B0gVopNc/O YsPw== X-Gm-Message-State: ABy/qLbbVee4aP6FsfHeQ2fXeMnNFS2S/l2FfeWhiwSme4lH+LrZa3Ym ftYW1MllR+kwrH/zndDFd4O0YIZ2QIc= 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> Precedence: bulk X-Mailing-List: kvmarm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: 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" 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