From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753049AbbJFQfM (ORCPT ); Tue, 6 Oct 2015 12:35:12 -0400 Received: from mail-wi0-f173.google.com ([209.85.212.173]:35710 "EHLO mail-wi0-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752734AbbJFQfI (ORCPT ); Tue, 6 Oct 2015 12:35:08 -0400 Subject: Re: [PATCH v3 0/3] uio: add MSI/MSI-X support to uio_pci_generic driver To: "Michael S. Tsirkin" References: <1443991398-23761-1-git-send-email-vladz@cloudius-systems.com> <20151005221651-mutt-send-email-mst@redhat.com> <56138867.4000006@cloudius-systems.com> <20151006171940-mutt-send-email-mst@redhat.com> <5613DD57.3000906@cloudius-systems.com> <20151006180050-mutt-send-email-mst@redhat.com> Cc: linux-kernel@vger.kernel.org, hjk@hansjkoch.de, corbet@lwn.net, gregkh@linuxfoundation.org, bruce.richardson@intel.com, avi@cloudius-systems.com, gleb@cloudius-systems.com, stephen@networkplumber.org, alexander.duyck@gmail.com From: Vlad Zolotarov Message-ID: <5613F838.70003@cloudius-systems.com> Date: Tue, 6 Oct 2015 19:35:04 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.1.0 MIME-Version: 1.0 In-Reply-To: <20151006180050-mutt-send-email-mst@redhat.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/06/15 18:13, Michael S. Tsirkin wrote: > On Tue, Oct 06, 2015 at 05:40:23PM +0300, Vlad Zolotarov wrote: >>> I'm guessing it doesn't enable MSI though, does it? >> Again, enabling MSI is a matter of a trivial patch configuring device >> registers on the device BAR. > No, not really. Sure that is! Look at pci_msi_set_enable(): it's a single read and then write, just like the code for bus master enabling. The msi capability address may be retrieved from lspci and then mapped for instance using sysfs. Configuring the MSI table is a few more reads and writes too but at the bottom line - it's a trivial code too... >