From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sasha Levin Subject: Re: [PATCH 1/2] kvm tools: Fix IRQ assignments Date: Fri, 06 May 2011 10:36:03 +0300 Message-ID: <1304667363.10534.5.camel@lappy> References: <1304666795-15251-1-git-send-email-levinsasha928@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: mingo@elte.hu, asias.hejun@gmail.com, gorcunov@gmail.com, prasadjoshi124@gmail.com, kvm@vger.kernel.org To: Pekka Enberg Return-path: Received: from mail-ww0-f44.google.com ([74.125.82.44]:45366 "EHLO mail-ww0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753944Ab1EFHgO (ORCPT ); Fri, 6 May 2011 03:36:14 -0400 Received: by wwa36 with SMTP id 36so3215794wwa.1 for ; Fri, 06 May 2011 00:36:13 -0700 (PDT) In-Reply-To: Sender: kvm-owner@vger.kernel.org List-ID: On Fri, 2011-05-06 at 10:29 +0300, Pekka Enberg wrote: > On Fri, May 6, 2011 at 10:26 AM, Sasha Levin wrote: > > virtio-blk needs a block of 4 IRQs (currently - staticly defined). > > Giving the initial IRQ of 15 causes breakage when adding more > > than one device. > > > > Signed-off-by: Sasha Levin > > Can we make the allocation dynamic instead? AFAICT, it could be a simple as > > int kvm__request_irq(struct kvm *kvm) > { > return kvm->next_irq++; > } > > that's done at device init time and then we'd just add "int irq" to > the individual struct devices. > > Pekka afaik, we need to have same IRQ pins for devices which may have different IRQ lines (All virtio-blk share same IRQ pin but different line, I assume it'll be same with different virtio devices). So mptable has to manage association between device type and the corresponding IRQ pin/line assignment, So dynamic assignment will be more of a call with device type and return IRQ pin + line - which makes it more complex than just allocating next free IRQ line. -- Sasha.