> Am 19.12.2013 um 08:02 schrieb "Aneesh Kumar K.V" > <aneesh.ku...@linux.vnet.ibm.com>: > > Alexander Graf <ag...@suse.de> writes: > >>> On 11.11.2013, at 15:02, Aneesh Kumar K.V <aneesh.ku...@linux.vnet.ibm.com> >>> wrote: >>> >>> From: "Aneesh Kumar K.V" <aneesh.ku...@linux.vnet.ibm.com> >>> >>> Don't try to compute these values. >>> >>> Signed-off-by: Aneesh Kumar K.V <aneesh.ku...@linux.vnet.ibm.com> >>> --- >>> >>> 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 <ag...@suse.de> >> 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 <ag...@suse.de> >> Signed-off-by: Avi Kivity <a...@redhat.com> >> >> 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.
Paul only mentioned DAR, not DSISR. Please verify whether 970 gives us a proper DAR value - we can then remove that part. But for DSISR I'm not convinced CPUs above 970 handle this correctly. So we would at least need a guest cpu check to find out whether the vcpu expects a working dsisr and emulate it then. I don't really fully understand the problem though. Why does the calculation break at all for you? Alex -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
