Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753361Ab0ASOXb (ORCPT ); Tue, 19 Jan 2010 09:23:31 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753325Ab0ASOXa (ORCPT ); Tue, 19 Jan 2010 09:23:30 -0500 Received: from thoth.sbs.de ([192.35.17.2]:24212 "EHLO thoth.sbs.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753320Ab0ASOX3 (ORCPT ); Tue, 19 Jan 2010 09:23:29 -0500 Message-ID: <4B55C05D.9000509@siemens.com> Date: Tue, 19 Jan 2010 15:23:25 +0100 From: Jan Kiszka User-Agent: Mozilla/5.0 (X11; U; Linux i686 (x86_64); de; rv:1.8.1.12) Gecko/20080226 SUSE/2.0.0.12-1.1 Thunderbird/2.0.0.12 Mnenhy/0.7.5.666 MIME-Version: 1.0 To: "Michael S. Tsirkin" CC: Davide Libenzi , Avi Kivity , "kvm@vger.kernel.org" , Linux Kernel Mailing List Subject: Re: [PATCH 1/2] kvm: fix spurious interrupt with irqfd References: <20100113171230.GB19798@redhat.com> <4B55B2B8.5090105@siemens.com> <20100119134827.GA28191@redhat.com> <4B55BBB6.2020901@siemens.com> <20100119140425.GA28410@redhat.com> In-Reply-To: <20100119140425.GA28410@redhat.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1289 Lines: 31 Michael S. Tsirkin wrote: >>>> I just wonder how broad >>>> the impact of a broken or non-existent eventfd subsystem for kvm-kmod >>>> is. Any thoughts welcome. >>> How do you handle kernels that don't export eventfd_ctx_fileget? >> Now that you mention it: not yet properly. So far we pass the file >> struct as pseudo eventfd_ctx around on < 2.6.31. But now that I peek >> into the struct in kvm_eventfd_ctx_remove_wait_queue, this should should >> crash. Guess I need to look up that module the same way as I acquire >> __wake_up_locked[_key]. > > This won't work that well: eventfd in upstream > sends us POLLHUP so we can close the structure, > in old kernels it doesn't so kernel will crash > when we try to reference the structure later. > OK, so any host kernel < 2.6.31 will never work for us. Mmh, then I could only close the gap 2.6.31..2.6.33. vhost will show up in 33... Will that version already be worth any eventfd wrapping? Jan -- Siemens AG, Corporate Technology, CT T DE IT 1 Corporate Competence Center Embedded Linux -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/