From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Date: Tue, 16 Oct 2012 11:01:37 +0000 Subject: Re: [PATCH 0/2] KVM: PPC: Support ioeventfd Message-Id: <507D3E91.6070909@redhat.com> List-Id: References: <1350302566-28889-1-git-send-email-agraf@suse.de> <507D3D4D.2090507@redhat.com> In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Alexander Graf Cc: KVM list , kvm-ppc@vger.kernel.org On 10/16/2012 12:59 PM, Alexander Graf wrote: > > On 16.10.2012, at 12:56, Avi Kivity wrote: > >> On 10/15/2012 02:02 PM, Alexander Graf wrote: >>> In order to support vhost, we need to be able to support ioeventfd. >>> >>> This patch set adds support for ioeventfd to PPC and makes it possible to >>> do so without implementing irqfd along the way, as it requires an in-kernel >>> irqchip which we don't have yet. >> >> It's not strictly required. You have an interrupt line leading to the >> core, no? You could have your irqfd trigger that. > > The irqfd code in KVM directly triggers the in-kernel irqchip. That's what this patch set is cleaning up: enable you to build ioeventfd support without in-kernel irqchip irqfd support. > > Vhost can work without in-kernel irqchip too, by listening to an eventfd (iiuc) in user space. That path works just fine with these patches applied. That's all true but it wasn't my point. I was asking whether you can enable irqfd without in-kernel irqchip. If your irq input is edge triggered then it's trivial. If it's level triggered then you can use the new resampling irqfd. -- error compiling committee.c: too many arguments to function From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH 0/2] KVM: PPC: Support ioeventfd Date: Tue, 16 Oct 2012 13:01:37 +0200 Message-ID: <507D3E91.6070909@redhat.com> References: <1350302566-28889-1-git-send-email-agraf@suse.de> <507D3D4D.2090507@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: KVM list , kvm-ppc@vger.kernel.org To: Alexander Graf Return-path: Received: from mx1.redhat.com ([209.132.183.28]:33948 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753558Ab2JPLBo (ORCPT ); Tue, 16 Oct 2012 07:01:44 -0400 In-Reply-To: Sender: kvm-owner@vger.kernel.org List-ID: On 10/16/2012 12:59 PM, Alexander Graf wrote: > > On 16.10.2012, at 12:56, Avi Kivity wrote: > >> On 10/15/2012 02:02 PM, Alexander Graf wrote: >>> In order to support vhost, we need to be able to support ioeventfd. >>> >>> This patch set adds support for ioeventfd to PPC and makes it possible to >>> do so without implementing irqfd along the way, as it requires an in-kernel >>> irqchip which we don't have yet. >> >> It's not strictly required. You have an interrupt line leading to the >> core, no? You could have your irqfd trigger that. > > The irqfd code in KVM directly triggers the in-kernel irqchip. That's what this patch set is cleaning up: enable you to build ioeventfd support without in-kernel irqchip irqfd support. > > Vhost can work without in-kernel irqchip too, by listening to an eventfd (iiuc) in user space. That path works just fine with these patches applied. That's all true but it wasn't my point. I was asking whether you can enable irqfd without in-kernel irqchip. If your irq input is edge triggered then it's trivial. If it's level triggered then you can use the new resampling irqfd. -- error compiling committee.c: too many arguments to function