From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id BC8FFC48BE8 for ; Mon, 24 Jun 2019 16:23:23 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 5499620673 for ; Mon, 24 Jun 2019 16:23:23 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5499620673 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:52970 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hfRkW-0003YC-Be for qemu-devel@archiver.kernel.org; Mon, 24 Jun 2019 12:23:21 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:55160) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hfRWs-00023z-Fs for qemu-devel@nongnu.org; Mon, 24 Jun 2019 12:09:15 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hfRWr-0004JQ-E8 for qemu-devel@nongnu.org; Mon, 24 Jun 2019 12:09:14 -0400 Received: from foss.arm.com ([217.140.110.172]:52816) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hfRWl-00047P-J8; Mon, 24 Jun 2019 12:09:09 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 723DF2B; Mon, 24 Jun 2019 09:09:03 -0700 (PDT) Received: from e103592.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 19E0E3F71E; Mon, 24 Jun 2019 09:09:01 -0700 (PDT) Date: Mon, 24 Jun 2019 17:09:00 +0100 From: Dave Martin To: Andrew Jones Message-ID: <20190624160859.GV2790@e103592.cambridge.arm.com> References: <20190621163422.6127-1-drjones@redhat.com> <20190621163422.6127-11-drjones@redhat.com> <20190624110535.GI2790@e103592.cambridge.arm.com> <20190624115553.ef22fdempvxkzzog@kamzik.brq.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190624115553.ef22fdempvxkzzog@kamzik.brq.redhat.com> User-Agent: Mutt/1.5.23 (2014-03-12) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 217.140.110.172 Subject: Re: [Qemu-devel] [PATCH v2 10/14] target/arm/kvm64: Add kvm_arch_get/put_sve X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "peter.maydell@linaro.org" , "richard.henderson@linaro.org" , "qemu-devel@nongnu.org" , "armbru@redhat.com" , "eric.auger@redhat.com" , "qemu-arm@nongnu.org" , "imammedo@redhat.com" , "alex.bennee@linaro.org" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Mon, Jun 24, 2019 at 12:55:53PM +0100, Andrew Jones wrote: > On Mon, Jun 24, 2019 at 12:05:35PM +0100, Dave Martin wrote: > > On Fri, Jun 21, 2019 at 05:34:18PM +0100, Andrew Jones wrote: > > > These are the SVE equivalents to kvm_arch_get/put_fpsimd. Note, the > > > swabbing is different than it is for fpsmid because the vector format > > > is a little-endian stream of words. > > > > Note, on big-endian hosts the FPSIMD view Vn and the SVE view Zn[127:0] > > of the FPSIMD/SVE common register bits has the opposite endianness for > > SVE_{GET,SET}_ONE_REG. > > > > This only matters if mixing the two views: just from this patch I don't > > know whether this is an issue for QEMU or not. > > I don't know either. My experience with the emulation side of QEMU is > mostly the zcr_write tweak in this series. And, TBH, I didn't put too > much thought into the endianness stuff, nor test this series with big > endian. Neither did I (at least beyond the "does it boot" level) -- hence the bug ;) And of course, few people are using big-endian, so nobody complained. Just flagging it up so it doesn't get missed! > Hopefully Richard can chime in on this. It would be interesting to know whether you do hit this issue somewhere, or whether you have a strong view about the clarification to the KVM ABI. Cheers ---Dave