From mboxrd@z Thu Jan 1 00:00:00 1970 From: Keir Fraser Subject: Re: [PATCH] Change spec of callback IRQ forPV-on-HVMonIA64 Date: Tue, 21 Nov 2006 11:33:10 +0000 Message-ID: References: Mime-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: "Tian, Kevin" , Doi.Tsunehisa@jp.fujitsu.com Cc: xen-devel , Alex Williamson List-Id: xen-devel@lists.xenproject.org On 21/11/06 10:56, "Tian, Kevin" wrote: >> OK, I now understand. Other OS tells xen GSI number as callback_irq, >> and then xen look up virtual interrupt controller to find appropriate >> vector by GSI number. This is the way to go. :-) >> >> Thanks a lot, >> Kevin >> > > Keir mentioned in another thread that he will change qemu to support > more GSIs (>16) soon, and this will become an issue with your patch > since you're only looking at isa_irq_to_vector. Is there any common > approach exported by linux kernel to find vector->GSI mapping in > driver? If not, maybe an alternative is to provide a callback_irq_type > which indicates whether the value is a GSI or vector? We plan to add a callback_vector type to the Xen interface for x86 HVM, as we will deliver event-channel notifications via an MSI-style poke directly into the IRR of the appropriate local APIC. We'll continue to support callback_irq type for compatibility. -- Keir