From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ian Campbell Subject: Re: [v3 12/13] arm: Allow the user to specify the GIC version Date: Wed, 1 Jul 2015 15:50:08 +0100 Message-ID: <1435762208.21469.295.camel@citrix.com> References: <1435748473-28812-1-git-send-email-julien.grall@citrix.com> <1435748473-28812-14-git-send-email-julien.grall@citrix.com> <21907.61579.913529.308479@mariner.uk.xensource.com> <5593FB2E.1090609@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail6.bemta3.messagelabs.com ([195.245.230.39]) by lists.xen.org with esmtp (Exim 4.72) (envelope-from ) id 1ZAJL5-0004jt-Lv for xen-devel@lists.xenproject.org; Wed, 01 Jul 2015 14:50:15 +0000 In-Reply-To: <5593FB2E.1090609@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: Julien Grall Cc: xen-devel@lists.xenproject.org, Ian Jackson , Wei Liu , stefano.stabellini@citrix.com List-Id: xen-devel@lists.xenproject.org On Wed, 2015-07-01 at 15:37 +0100, Julien Grall wrote: > > AFIACT the default is "offer the guest the hardware's native version". > > This is true when the domain is firstly created. But this will be > confusing if the user decide to migrate the guest to a platform where > the native GIC is different. > > This is a valid use-case, though we don't support migration yet, and the > guest will expect to get the same virtual GIC (the IRQ controller driver > can't be changed). I think an option "native" which is documented to be latching on the host the guest is started on is absolutely fine, and avoids needing to faff around turning default into native at the interface and/or parsing stage. Upon migration the config should have been updated to reflect whatever decision Xen made when the guest was first started. Ian.