From mboxrd@z Thu Jan 1 00:00:00 1970 From: Julien Grall Subject: Re: [Draft F] Xen on ARM vITS Handling Date: Fri, 12 Jun 2015 09:09:48 -0400 Message-ID: <557ADA1C.8050700@citrix.com> References: <1434015607.30003.137.camel@citrix.com> <1434099156.30003.196.camel@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1434099156.30003.196.camel@citrix.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Ian Campbell , Vijay Kilari Cc: manish.jaggi@caviumnetworks.com, Julien Grall , Stefano Stabellini , xen-devel List-Id: xen-devel@lists.xenproject.org Hi Ian, On 12/06/2015 04:52, Ian Campbell wrote: > On Fri, 2015-06-12 at 14:07 +0530, Vijay Kilari wrote: > So pLPIs must be routed at device assignment time because in the vLPI > configuration table trap there is no mapping back to a single pLPI. I just remembered the exact reason that made use to differ SPI enabling. When the device is assigned, the domain VCPUs are still down (even VCPU0). If we receive an interrupt before the VCPU0 is unpaused, the interrupt will be lost. Same if the interrupt is not yet configured (i.e before the vITS setup correctly the table) with your proposal. This could happen when the device is not quiescent. We had this issue on the vexpress at boot time when the network card was trying to send an interrupt before DOM0 is setup. Regards, -- Julien Grall