From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752927AbbJFOqj (ORCPT ); Tue, 6 Oct 2015 10:46:39 -0400 Received: from mx1.redhat.com ([209.132.183.28]:52060 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751190AbbJFOqh (ORCPT ); Tue, 6 Oct 2015 10:46:37 -0400 Date: Tue, 6 Oct 2015 17:46:31 +0300 From: "Michael S. Tsirkin" To: Avi Kivity Cc: Greg KH , Vlad Zolotarov , linux-kernel@vger.kernel.org, hjk@hansjkoch.de, corbet@lwn.net, bruce.richardson@intel.com, avi@cloudius-systems.com, gleb@cloudius-systems.com, stephen@networkplumber.org, alexander.duyck@gmail.com Subject: Re: [PATCH v3 2/3] uio_pci_generic: add MSI/MSI-X support Message-ID: <20151006173846-mutt-send-email-mst@redhat.com> References: <1443991398-23761-1-git-send-email-vladz@cloudius-systems.com> <1443991398-23761-3-git-send-email-vladz@cloudius-systems.com> <20151005031159.GB27303@kroah.com> <56123493.9000602@scylladb.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <56123493.9000602@scylladb.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Oct 05, 2015 at 11:28:03AM +0300, Avi Kivity wrote: > Eventfd is a natural enough representation of an interrupt; both kvm and > vfio use it, and are also able to share the eventfd, allowing a vfio > interrupt to generate a kvm interrupt, without userspace intervention, and > one day without even kernel intervention. eventfd without kernel intervention sounds unlikely. kvm might configure the cpu such that an interrupt will not trigger a vmexit. eventfd seems like an unlikely interface to do that: with the eventfd, device triggering it has no info about the interrupt so it can't send it to the correct VM. -- MST