From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e28smtp03.in.ibm.com (e28smtp03.in.ibm.com [122.248.162.3]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 0A6582C00AA for ; Thu, 19 Dec 2013 18:03:19 +1100 (EST) Received: from /spool/local by e28smtp03.in.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 19 Dec 2013 12:32:55 +0530 Received: from d28relay04.in.ibm.com (d28relay04.in.ibm.com [9.184.220.61]) by d28dlp01.in.ibm.com (Postfix) with ESMTP id 56AACE0024 for ; Thu, 19 Dec 2013 12:35:19 +0530 (IST) Received: from d28av01.in.ibm.com (d28av01.in.ibm.com [9.184.220.63]) by d28relay04.in.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id rBJ72lUL54919326 for ; Thu, 19 Dec 2013 12:32:48 +0530 Received: from d28av01.in.ibm.com (localhost [127.0.0.1]) by d28av01.in.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id rBJ72owg012601 for ; Thu, 19 Dec 2013 12:32:50 +0530 From: "Aneesh Kumar K.V" To: Alexander Graf Subject: Re: [PATCH] powerpc: book3s: kvm: Use the saved dsisr and dar values In-Reply-To: <0AB88010-F2B7-44A1-8FA9-2A40079706BB@suse.de> References: <1384178577-23721-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> <0AB88010-F2B7-44A1-8FA9-2A40079706BB@suse.de> Date: Thu, 19 Dec 2013 12:32:50 +0530 Message-ID: <87bo0d9vc5.fsf@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain Cc: Paul Mackerras , linuxppc-dev@lists.ozlabs.org, kvm-ppc@vger.kernel.org, "kvm@vger.kernel.org mailing list" List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Alexander Graf writes: > On 11.11.2013, at 15:02, Aneesh Kumar K.V wrote: > >> From: "Aneesh Kumar K.V" >> >> Don't try to compute these values. >> >> Signed-off-by: Aneesh Kumar K.V >> --- >> >> NOTE: I am not sure why we were originally computing dsisr and dar. So may be >> we need a variant of this patch. But with this and the additional patch >> "powerpc: book3s: PR: Enable Little Endian PR guest" I am able to get a Little Endian >> PR guest to boot. > > It's quite easy to find out - git blame tells you all the history and points you to commit ca7f4203b. > > commit ca7f4203b9b66e12d0d9968ff7dfe781f3a9695a > Author: Alexander Graf > Date: Wed Mar 24 21:48:28 2010 +0100 > > KVM: PPC: Implement alignment interrupt > > Mac OS X has some applications - namely the Finder - that require alignment > interrupts to work properly. So we need to implement them. > > But the spec for 970 and 750 also looks different. While 750 requires the > DSISR and DAR fields to reflect some instruction bits (DSISR) and the fault > address (DAR), the 970 declares this as an optional feature. So we need > to reconstruct DSISR and DAR manually. > > Signed-off-by: Alexander Graf > Signed-off-by: Avi Kivity > > Read this as "on 970, alignment interrupts don't give us DSISR and DAR of the faulting instruction" as otherwise I wouldn't have implemented it. > > So this is clearly a nack on this patch :). I can possibly do a if (cpu_has_feature(CPU_FTR_ARCH_201)). But do we need to do that ? According to Paul we should always find DAR. -aneesh