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 EC777E95A8E for ; Mon, 9 Oct 2023 02:35:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345006AbjJICf6 (ORCPT ); Sun, 8 Oct 2023 22:35:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51828 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231542AbjJICf5 (ORCPT ); Sun, 8 Oct 2023 22:35:57 -0400 Received: from zeniv.linux.org.uk (zeniv.linux.org.uk [IPv6:2a03:a000:7:0:5054:ff:fe1c:15ff]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 59FB0A4; Sun, 8 Oct 2023 19:35:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=linux.org.uk; s=zeniv-20220401; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=MU7v5qu9yPgnI8R82udS5Goc2VlcNgXX+qckqeqZ3bk=; b=IfnSPLykY5r++NKkjhZPUlGZzv kzfVK3Z1XcTyVf44RHNahVP4B8zG/qFSONbonhjM8N7Zms1wb/cH9nloTEaJoADv+hVH1wVZK/A2R TQ1dG5bK//yRiqkIm26n2iYkqvw7zwbFOaFSexj0uM1XnQ7c3CoXB1cx8O4kUTxHtIGxHydHCrzYo a+u8Gx/dBFhzCLIL+hGeMdFxRKruCcG/KTvcQLOXRmlbbqK6Lm0UsngE6eqK3lRhfuc4gj+lhMQqP LW2eDxIpsaSvFe16PmtKqKOjr6IqT97opBin71WYYLvo7zL815yLIVOnKhkItSfoGb4fKIDkwOhuj fGj9fXXw==; Received: from viro by zeniv.linux.org.uk with local (Exim 4.96 #2 (Red Hat Linux)) id 1qpg7e-00H4Rt-2s; Mon, 09 Oct 2023 02:35:54 +0000 Date: Mon, 9 Oct 2023 03:35:54 +0100 From: Al Viro To: Sean Christopherson Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, Paolo Bonzini Subject: Re: [PATCH gmem FIXUP] kvm: guestmem: do not use a file system Message-ID: <20231009023554.GE800259@ZenIV> References: <20230928180651.1525674-1-pbonzini@redhat.com> <169595365500.1386813.6579237770749312873.b4-ty@google.com> <20231009022248.GD800259@ZenIV> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20231009022248.GD800259@ZenIV> Sender: Al Viro Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Mon, Oct 09, 2023 at 03:22:48AM +0100, Al Viro wrote: > On Thu, Sep 28, 2023 at 07:22:16PM -0700, Sean Christopherson wrote: > > On Thu, 28 Sep 2023 14:06:51 -0400, Paolo Bonzini wrote: > > > Use a run-of-the-mill anonymous inode, there is nothing useful > > > being provided by kvm_gmem_fs. > > > > > > > > > > Applied to kvm-x86 guest_memfd, thanks! > > > > [1/1] kvm: guestmem: do not use a file system > > https://github.com/kvm-x86/linux/commit/0f7e60a5f42a > > Please, revert; this is completely broken. anon_inode_getfile() > yields a file with the same ->f_inode every time it is called. > > Again, ->f_inode of those things is shared to hell and back, > very much by design. You can't modify its ->i_op or anything > other field, for that matter. No information can be stored > in that thing - you are only allowed to use the object you've > passed via 'priv' argument. BTW, note that all those suckers will end up sharing the page cache; looks like that's not what you want to get... > NAKed-by: Al Viro