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 EFC4CCD6136 for ; Mon, 9 Oct 2023 20:20:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1378595AbjJIUUP (ORCPT ); Mon, 9 Oct 2023 16:20:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52156 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1378544AbjJIUUL (ORCPT ); Mon, 9 Oct 2023 16:20:11 -0400 Received: from mail-yw1-x1149.google.com (mail-yw1-x1149.google.com [IPv6:2607:f8b0:4864:20::1149]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3E74694 for ; Mon, 9 Oct 2023 13:20:09 -0700 (PDT) Received: by mail-yw1-x1149.google.com with SMTP id 00721157ae682-5a22eb73cb3so88386057b3.3 for ; Mon, 09 Oct 2023 13:20:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1696882808; x=1697487608; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=X6+GJ5cI4z2TlJw5nJFvkv7FETWY362gjhrvcMB9XFc=; b=LYMPNRYaGtJ0B7jCpzJLOeAOt4N5rEjxApu3zMBe7oeVCCTl5ExTQEGkDjkQ2VquMi 5JzYk5VrNtmkSZEbCJr7LuTLXgPgdswazaskUq4r/nb2MwvQlY/7bin9K4mSEOb1nh23 aQGNHQR5OCxv8ouCA5FnKE6fg5l2yOVe8wE0MnBeOdtEv7qlv4UWIW+YwoP7fCYOmhM7 IcxngCv54vmqWR2K7rpaTfwzdEBwnwv880xHoxJbZg5AP9sNmeXJ1XIbmh7dlza/cfMf uAMOiB3KSGkQK0ZsaI/eD8AuVIIoMseYxZAZliaW6DQNB32qGbBHGpSYxiTQAKR6ts1H BB/w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1696882808; x=1697487608; 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=X6+GJ5cI4z2TlJw5nJFvkv7FETWY362gjhrvcMB9XFc=; b=E7CpW7ykcZzmXXwbd8+2w2ueW5nHjblkAAm8BnW3A3xBtiBEyhOdT3OGkMp6uDKWuE um/RhN7aWpauxnDYCwhuKLERosy7BZPcc3WzoYPvPDhtUNRXaPHlLgI+qNd936EJh+iH PfWR7c8kPRP4Kpf1V2vNLitgOnDVuROQNNj/EMZOKmM0CgORVS0QMh6gMqG19ea8txHe Yy9N5IpxuDIzU35xCdbu70KuehMudzAGDs+eV+b8rUUV8RUQZ026kdVEHlWlQctSNooj kSBfPc2cEA5rvsecaxJ7I5/ZuRcZ490EaIbm81AW58X4FZYehLLvsi09mwqfAXB+Q+DT FgqA== X-Gm-Message-State: AOJu0YyIZitdcvcI7tCYE37ELz6qRuAPQ2YijN1LqIoXZSngbjML2BqH iNMwAHAU5kh8v8O/ys+/WYeyq3dC/c8= X-Google-Smtp-Source: AGHT+IFY1JX42tQvUiQbHjxHOd20j5m7plZ8L4JheDy574ZvKTNtyQEZK75VDZPRx5P3o6rzL4rbdqXGQyM= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a5b:b50:0:b0:d80:904d:c211 with SMTP id b16-20020a5b0b50000000b00d80904dc211mr241176ybr.7.1696882808446; Mon, 09 Oct 2023 13:20:08 -0700 (PDT) Date: Mon, 9 Oct 2023 13:20:06 -0700 In-Reply-To: <20231009200608.GJ800259@ZenIV> Mime-Version: 1.0 References: <20230928180651.1525674-1-pbonzini@redhat.com> <169595365500.1386813.6579237770749312873.b4-ty@google.com> <20231009022248.GD800259@ZenIV> <20231009200608.GJ800259@ZenIV> Message-ID: Subject: Re: [PATCH gmem FIXUP] kvm: guestmem: do not use a file system From: Sean Christopherson To: Al Viro Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, Paolo Bonzini Content-Type: text/plain; charset="us-ascii" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Oct 09, 2023, Al Viro wrote: > On Mon, Oct 09, 2023 at 07:32:48AM -0700, Sean Christopherson wrote: > > > Yeah, we found that out the hard way. Is using the "secure" variant to get a > > per-file inode a sane approach, or is that abuse that's going to bite us too? > > > > /* > > * Use the so called "secure" variant, which creates a unique inode > > * instead of reusing a single inode. Each guest_memfd instance needs > > * its own inode to track the size, flags, etc. > > */ > > file = anon_inode_getfile_secure(anon_name, &kvm_gmem_fops, gmem, > > O_RDWR, NULL); > > Umm... Is there any chance that your call site will ever be in a module? > If not, you are probably OK with that variant. Yes, this code can be compiled as a module. I assume there issues with the inode outliving the module?