From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pavel Fedin Subject: RE: [PATCH] KVM: arm/arm64: Add VGICv3 save/restore API documentation Date: Thu, 08 Oct 2015 10:17:09 +0300 Message-ID: <003a01d10199$58e96590$0abc30b0$@samsung.com> References: <1444247430-14808-1-git-send-email-christoffer.dall@linaro.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: kvm@vger.kernel.org, 'Andre Przywara' , 'Peter Maydell' , 'Marc Zyngier' , 'Eric Auger' To: 'Christoffer Dall' , kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org Return-path: Received: from mailout1.w1.samsung.com ([210.118.77.11]:38172 "EHLO mailout1.w1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751605AbbJHHRN (ORCPT ); Thu, 8 Oct 2015 03:17:13 -0400 Received: from eucpsbgm1.samsung.com (unknown [203.254.199.244]) by mailout1.w1.samsung.com (Oracle Communications Messaging Server 7.0.5.31.0 64bit (built May 5 2014)) with ESMTP id <0NVW00IBD48M6S90@mailout1.w1.samsung.com> for kvm@vger.kernel.org; Thu, 08 Oct 2015 08:17:10 +0100 (BST) In-reply-to: <1444247430-14808-1-git-send-email-christoffer.dall@linaro.org> Content-language: ru Sender: kvm-owner@vger.kernel.org List-ID: Hello! > + The mpidr encoding is based on the affinity information in the > + architecture defined MPIDR, and the field is encoded as follows: > + | 63 .... 56 | 55 .... 48 | 47 .... 40 | 39 .... 32 | > + | Aff3 | Aff2 | Aff1 | Aff0 | One concern about this... Does it already have "We are Bosses, we Decided it, It's not subject to change, We do not care" status? Actually, current approach with using index instead of Aff bits works pretty well. It works fine with qemu too, because internally qemu also maintains CPU index, which it uses for GICv2 accesses. Keeping index allows to reuse more code, and provides better backwards compatibility. So could we do this? Kind regards, Pavel Fedin Expert Engineer Samsung Electronics Research center Russia