From mboxrd@z Thu Jan 1 00:00:00 1970 From: Radim =?utf-8?B?S3LEjW3DocWZ?= Subject: Re: [Patch v5] x86: irq_comm: Add check for RH bit in kvm_set_msi_irq Date: Tue, 21 Apr 2015 14:44:55 +0200 Message-ID: <20150421124454.GA15976@potion.brq.redhat.com> References: <5502FEDB.3030606@gmail.com> <20150318225225.GA8702@amt.cnet> <550A1F6A.6030602@gmail.com> <20150319010932.GA18338@amt.cnet> <20150319130015.GA16070@potion.brq.redhat.com> <550B5309.1090805@gmail.com> <55364012.2040004@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: James Sullivan , Marcelo Tosatti , kvm@vger.kernel.org, gleb@kernel.org To: Paolo Bonzini Return-path: Received: from mx1.redhat.com ([209.132.183.28]:53414 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750714AbbDUMpD (ORCPT ); Tue, 21 Apr 2015 08:45:03 -0400 Content-Disposition: inline In-Reply-To: <55364012.2040004@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: 2015-04-21 14:18+0200, Paolo Bonzini: > On 19/03/2015 23:51, James Sullivan wrote: > > I played around with native_compose_msi_msg and discovered the following: > > > > * dm=0, rh=0 => Physical Destination Mode > > * dm=0, rh=1 => Failed delivery > > * dm=1, rh=0 => Logical Destination Mode, No Redirection > > * dm=1, rh=1 => Logical Destination Mode, Redirection > > > > So it seems to be the case that logical destination mode is used whenever > > DM=1, regardless of RH. Furthermore, the case where DM=0 and RH=1 is > > undefined, as was indicated in the closing response to the thread in > > https://software.intel.com/en-us/forums/topic/288883 : > > So this means this patch is not necessary, right? Yes, and this patch was obsolete even before; the latest version is [PATCH v4 0/2] kvm: x86: Implement handling of RH=1 for MSI delivery in KVM which delivers DM=1+RH=1 as lowest priority. (Several unfortunate things made this quite confusing ...)